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  • Articles  (1,933)
  • Biochemistry and Biotechnology  (1,933)
  • 1980-1984  (1,710)
  • 1960-1964  (223)
  • 1925-1929
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  • Articles  (1,933)
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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 2
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 19-31 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A process is described in which the baboon endogenous virus (BaEV) is produced under optimum conditions in cell culture, and concentrated by hollow-fiber ultrafiltration technology under conditions of large-scale production. This system has advantages over conventional systems in that the flow rate is increased 2.5-fold during concentration. Thermal inactivation of BaEV was retarded by the addition of lactose glutamate to the harvested tissue culture fluid. After concentration, at least 91% of the virus RNA-directed DNA polymerase is recovered with a concomitant increase in infectious virus. Materials needed for modifying described systems may be obtained from commercial sources.
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  • 3
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 1-17 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Data reported here and previously indicate that when dextrin is hydrolyzed in the presence of immobilized glucoamylase, use of a larger average molecular weight substrate leads to lower overall rates of hydrolysis, while the maltose concentration during the bulk of the reaction and the maximum glucose concentration are lower than when the soluble form of the enzyme is employed under the same conditions. Computer simulation of the system demonstrated that all three observations were caused by pore diffusion limitation: the first by slow diffusion of substrate, the second by slow diffusion of intermediates, and the third by slow diffusion of glucose. Follow-up experiments with glucoamylase immobilized to particles of different sizes confirmed this finding, as results with the smallest beads were identical to those with soluble glucoamylase.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 33-53 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A simple model is developed for the energy transformation in growing microbial systems. The model is based on a linear equation for ATP consumption in the processes of growth and maintenance. A combination of this equation with macroscopic balances for the various components, the systems exchanges with the environment, and application of the concepts of the elementary balance allow the derivation of linear equations for the exchange of substrate, oxygen, and carbon dioxide with the environment. For growth on one sole carbon and energy source the model allows the definition of a critical substrate yield are expected and below which is decreasing substrate yield and energy supply growth limitation are expected. This restriction can be interpreted in a variety of other ways. It supplies a rationale for non-energy-production-coupled transfer of hydrogen to oxygen or wasteful expenditure of ATP in growth on highly reduced substrates. It also allows the formulation of a limit to the maximum yield on oxygen that can never be exceeded in growth on highly reduced substrates.
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  • 5
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 55-64 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The phosphodiesterase from calf spleen (EC 3.1.4.18) was immobilized on several supports. Some properties of the most suitable enzyme support system - calf spleen phosphodiesterase bound to agarose-Concanavalin A - were investigated, e.g., pH dependence, influence of ionic strength of the buffer medium, and Zn2+-ion inhibition. The immobilized spleen phosphodiesterase showed about 60% of the activity of the free enzyme: the activity toward several oligonucleotide test substrates was unchanged for two months.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 79-88 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A procedure for large-scale preparation of a lectin from Crotalaria juncea seeds is described. The method involve fractionation by pH- and ammonium sulfate precipitation followed by biospecific affinity chromatography. The adsorbent used for the affinity chromatography was prepared by coupling galactose to Sepharose 6B activated with divinylsulfone. A comparison of different apparatus and techniques involved in the preparation is discussed. The yield and quality of the lectin prepared at a large scale were comparable with laboratory-scale preparation. From 50 kg Crotalaria juncea beans, 14.4 g Crotalaria lectin were obtained.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 65-77 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This research examined culture parameters influencing the rate of degradation of lignin in lignocellulosic substrates by the Basidiomycete Phanerochaete chrysosporium. Thermomechanical pulps prepared from western hemlock (Tsuga heterophylla) and red alder (Alnus rubra) were chosen as model substrates. Degradation of lignin in shallow, liquid-phase, stationary cultures was 10 times as rapid as in agitated cultures. Lignin degradation was at least 50% more rapid in cultures under 100% O2 than in those under air. Addition of 0.12% nutrient N (dry pulp basis) increased the rate of lignin degradation two- to fivefold; 1.2% added N at first suppressed, then stimulated, lignin degradation. Lignin in the alder pulp was degraded over five times as rapidly as in the hemlock pulp. Addition of glucose (35% of dry pulp) to the pulps containing 0.12% added N completely suppressed polysaccharide depletion during two weeks, but did not influence lignin degradation. The maximum rate of lignin degradation was 3%/day over a two-week incubation, or approximately 2.9 mg/mg fungal cell protein/day. The influence of the examined parameters was in complete accord with those found earlier for synthetic 14C-lignin metabolism by P. chrysosporium.
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  • 8
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 89-106 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Three feedback strategies for the on-line control of cell densities in a mixed-culture system have been examined. A competitive mixed-culture system of Candida utilis and Corynebacterium glutamicum grown on glucose as the limiting carbon source was modeled using Monod growth kinetics. First-order time constants were added to simulate transient growth effects. Multivariable feedback control of cell densities by manipulation of substrate feed and dilution rate was investigated. Feedback strategies directed to minimizing control interactions were found to be superior to classical feedback. Transients in the growth-rate response produced oscillations in cell density and required retuning of control constants. The relative time constants of the two species were important, with the largest oscillations resulting when the faster growing organism had the faster time constant.
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  • 9
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Studies were made of the death kinetics of Escherichia coli cells heated at 46 to 56°C in 0.05M phosphate buffer (pH 7.0) containing either an amphoteric surfactant (Tego 15DL, 1-10 μg/ml) or sorbic acid (0.5 to 3%). A linear relationship was obtained on the Arrhenius plot for the death of cells heated with each antimicrobial agent. The kinetics of the action of the surfactant, however, differed from that of sorbic acid. With the amphoteric surfactant, the activation enthalpy of the death reaction decreased from 108 to 51 kcal/mol as the concentration of surfactant was increased in the range tested although the death rate remained high; whereas with sorbic acid the activation enthalpy remained fairly constant (104 ± 9 kcal/mol) independent of its concentration and the death rate was similarly high. Further, in the action of the amphoteric surfactant, a thermodynamic compensation effect was observed, the compensation temperature being 334°K (61°C), i.e., relatively close to the observed temperatures. For sorbic acid, however, this temperature seemed to be too high to observe when determined from the Arrhenius plot. The data of the dependency of the death-rate constant upon the concentration of antimicrobial agent indicated a similar difference in the action of the two agents. Based on our results and on data obtained by other workers, we propose that antimicrobial agents that enhance cellular death induced by heating can be characterized into two types.
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  • 10
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 119-136 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The steroid transformation of hydrocortisone to prednisolone, combining the two techniques of immobilized whole cells and high steroid concentrations, was investigated and found to be a feasible process. Freeze-dried Corynebacterium simplex cells were immobilized in collagen, tanned with glutaraldehyde, and cast into a membrane. The reaction was studied at hydrocortisone concentrations ranging from 5 to 50 mg/ml. The following aspects of the system were examined: (1) the substrate concentration effect upon the reaction; (2) the effect of enzyme concentration; (3) the rate-concentration relationship; and (4) the product inhibition characteristics of the system. The optimal substrate concentration was found to be 15 mg/ml of a membrane concentration of 80 mg/ml. This reaction attained an 80% conversion in 48 hr. A liner relation was found between the initial reaction rate and membrane concentration. One can thus increase the net production of steroid per unit volume and time by increasing the membrane levels. A physical limit to this increase occurred at membrane concentrations greater than 125 mg/ml. The rate-concentration relationship was linear when graphed on a Line weaver-Burk plot: giving a Km′ and Vm′ value of 5.39 mg/ml and 0.556 mg/ml/hr, respectively. When the data were tested for competitive product inhibition, the curves fitted the experimental points fairly well and produced Km′ and Vm′ values of 4.52 mg/ml and 0.566 mg/ml/hr, respectively. Product inhibition experiments showed that the inhibition was not purely competitive. At low substrate concentrations, product inhibited the enzyme; at high substrate concentrations, the enzyme was first stimulated and then depressed by increasing levels of products. This behavior has been analyzed and shown to be possibly a result of the information of a tertiary intermediate produced during the reaction.
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  • 11
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Many changes that occur in a cell during the cell cycle can be demonstrated in synchronous cultures and can reveal dimensions of cell metabolism not attainable by the study of balanced growth of asynchronous populations in batch cultures or the steady state in chemostat cultures. The release of 14CO2 from specifically labeled glucose by phased (continuously synchronized) cultures follows a characteristic pattern (profile) that depends upon the stage in the cell cycle and the period of labeling used. Successive profiles throughout a cycle showed differences that were altered under different nutrient-limiting growth conditions. Profiles obtained with glucose-1-14C, glucose-2-14C, glucose-3,4-14C, and glucose-6-14C and phased cells of Candida utilis under N-, P-, and C-limited growth demonstrated the variable character of the metabolic activity that occurred in the cells while contour changes within the profiles across the cycle indicated possible correlations with activities of the hexose monophosphate, Embden-Meyerhof-Parnas, and tricarboxylic acid cycle pathways during the cell cycle. The basis of these changes and their use as elementary parameters for study of problems of physiological changes in vivo are considered.
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  • 12
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A comparative study was conducted into the immobilization of β-galactosidase, albumin, and γ-globulin on an epoxy-activated polyacrylic matrix (oxirane C, Röhm-Pharma GmbH, Darmstadt). The kinetic parameters of the immobilized β-galactosidase were investigated with three kinds of miniaturized analytical reactors: namely, stirred batch, continuous stirred-tank, and packed-bed reactors. The optimum binding conditions, saturation activity and Michaelis constant of immobilized β-galactosidase are given, together with determinations of the binding capacity of the oxirane C matrix for the three proteins investigated. For beta;-galactosidase a saturation activity of 1300 U/g oxirane C was reached. The maximum binding, achieved by experiment, was 140 mg/g with 0.69 yield for albumin, 120 mg/g with 0.61 yield for γ-globulin, and 40 mg/g with 0.42 yield for β-galactosidase. From these data the inner surface of the matrix as a function of the size of the bound proteins was estimated.
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  • 13
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 177-199 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The susceptibility of cellulose to enzymatic hydrolysis is affected by the structural features of cellulosic materials. It has been suggested that the crystallinity and surface area of cellulose fibers are the most important structural features in this regard. This study investigated in depth the relative effects of these two structural features upon the enzymatic hydrolysis of cellulose and the change of the structural parameters of cellulose during the course of hydrolysis. It was found that the hydrolysis rate is mainly dependent upon the fine structural order of cellulose which can best be represented by the crystallinity rather than the simple surface area. Monitoring the changes in the structural parameters during the course of reaction showed that surface area is not a major limiting factor that slows hydrolysis in its late stages as has been suggested. This information concerning structural features is used to elucidate the mode of action of cellulase.
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  • 14
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 215-219 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 15
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 201-214 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new method was developed for estimating the volumetric oxygen transfer coefficient, kLa, in a fermentor. Various methods were investigated for the on-line estimation of kLa with an analog computer employing a steepest-descent calculation technique. The method by which kLa is estimated (by minimizing the error residue of the model) was found to be very applicable. A method for the simultaneous estimation of the volumetric oxygen transfer coefficient and respiration rate in biological systems is also presented.
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  • 16
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    Biotechnology and Bioengineering 22 (1980), S. 221-226 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 17
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 18
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    Biotechnology and Bioengineering 22 (1980), S. 237-241 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 19
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 20
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    Biotechnology and Bioengineering 22 (1980), S. 243-246 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 21
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    Biotechnology and Bioengineering 22 (1980), S. 247-251 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 22
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 23
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 271-287 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two types of polyethylenimine-coated glass microbeads (13-44 μm) were synthesized and used for the immobilization of glucose oxidase from Aspergillus niger and catalase from A. niger and beef liver. The two types of beads were distinguishable by differences in their surface topography. Immobilizations were performed by adsorption followed by treatment with glutaraldehyde. The immobilized-enzyme activities per unit support of all of the enzymes tested were compared with and found to be superior to the immobilized activities attainable on aminopropyl-activated glass microbeads. When enzyme was present in less than saturating amounts, the coated beads were able to remove 100% of the glucose oxidase activity initially present in the immobilization solution, with 78-87% of that activity expressed on the support surface. Bound glucose oxidase was more stable to thermal inactivation than native enzyme.
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  • 24
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    Biotechnology and Bioengineering 22 (1980), S. 255-270 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A growth model for Claviceps purpurea in submerged batch culture is presented. In developing the model, the basic principles of the growth and the morphological properties of C. purpurea are considered. The growth of C. purpurea is assumed to occur in a three-step manner; the first step involves the assimilation and the growth of cells; the second one involves cell division, and the third one involves transformation of the mature cells to a state where they have no ability to divide but do have the ability to produce ergot alkaloids and then they gradually die. Inorganic phosphate is assumed to be the limiting substrate for the first and the second steps in conditions of carbon source being in excess. The model constants are determined by model simulation and graphical searching techniques to find the minimum value of the absolute difference between the experimental and the simulated curves for biomass, alkaloids, and sucrose.
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  • 25
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Using continuous and fed-batch penicillin fermentation systems some important metabolic parameters have been determined for the purpose of achieving process improvement and better process control. The specific uptake rates determined under the optimal conditions are: 0.33 mmol hexose/g cell/hr, 1.6 mmol oxygen/g cell/hr, 2mg NH3-nitrogen/g cell/hr, 0.6 mg PO4-phosphorus/g cell/hr, 2.8 mg SO4-sulfur/g cell/hr, 1.8 mg phenyl acetic acid/g cell/hr. It was also found that during the production phase, or idiophase, the specific growth rate should be maintained at about 0.015 hr-1 in order to support the maximum penicillin productivity of the given strain. Based on the results of this study a significant process improvement has been achieved through proper control of the supply and demand of the important nutrients and oxygen.
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  • 26
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    Biotechnology and Bioengineering 22 (1980), S. 299-310 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An enzyme electrode is described for quantitative determination of phenol at micromolar concentrations. Immobilized phenol hydroxylase is attached to the surface of a Clark oxygen electrode. The Maximum rate of oxygen consumption is linearly dependent on phenol concentration over the 0.5-50μM range. The electrode can be used for at least 150 assays without an activity loss. Readout is very rapid - within 30 sec of sample addition. The electrode response is independent of pH between pH 6.5 and 9.5. The response increases linearly with temperature in the interval 10-40°C. It is necessary to incubate the enzyme electrode in a buffer containing NADPH for a few minutes before the addition of sample. This is to make the electrode response independent of the diffusion rate of this cosubstrate. This and other diffusional effects on the performance of the phenol electrode are discussed.
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  • 27
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    Biotechnology and Bioengineering 22 (1980), S. 311-321 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: β-Galactosidase and other enzymes were immobilized on p-amino-carbanilated derivatives of cellulose and methylol cellulose using the diazo method and through glutaraldehyde. The optimum conditions for coupling cellulose tri-(p-amino-carbanilate) (CTAC) to β-galactosidase were established. The diazo coupling method with CTAC gave greater activity than with glutaraldehyde when coupled to β-galactosidase (Escherichia coli). The stability of the CTAC-β-galactosidase system was examined. The disubstituted p-amino-carbanilate derivative (CDAC) gave a lower activity, whereas the methylol analog (MCTAC) gave slightly greater activity. The CTAC was also used to immobilize glucose oxidase, trypsin, pepsin, and papain.
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  • 28
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    Biotechnology and Bioengineering 22 (1980), S. 353-362 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Bacteria grown on methanol exhibit a poor efficiency of energy conservation, which is mainly due to the low P/O ratio of 1 associated with methanol oxidation. Thermodynamic considerations indicate that a P/O ratio of at least 2 is possible for this step in substrate oxidation. This low efficiency of energy conservation is reflected in the yield values on methanol, which are very important in the consideration of biomass production from methanol. Unfortunately in continuous culture there is no obvious way to select for organisms with a greater efficiency of energy conservation.
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  • 29
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    Biotechnology and Bioengineering 22 (1980), S. 323-335 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Enzyme stability studies have been reinvestigated under the conditions used for cellulose hydrolysis (pH 4.8, 50°C, 24 hr). The cellobiohydrolase (CBH) component as measured on Avicel is less stable than other enzymes of the cellulase complex, and is 60% inactivated by merthiolate (and other Hg compounds) under the above conditions. Endo-β-1,4-glucanase is much more stable, and more resistant to merthiolate and other compounds. Under unshaken conditions the Avicelase of the Rutgers strain C 30 shows greater stability to heat than that of other available strains. Biocides must be selected not only for their ability to prevent contamination, but also for their compatibility with cellulases. Tetracycline and chlortetracycline are inexpensive, effective in very low concentrations, have no harmful effect on the enzymes, and are compatible with the yeasts that subsequently grow on the sugar solutions to produce alcohol. Attempts have been made to stabilize the enzymes by chemical modification in such a way as to maintain their solubility. Glutaraldehyde treatment greatly increased the enzyme size, lowered the pI values, and gave a slight shift in the pH activity curve. There was, unfortunately, no increase in enzyme stability, and the activity of enzymes on solid celluloses was adversely affected. Shaking greatly reduced the hydrolysis of Avicel by Trichoderma reesei C 30 enzyme. The adverse effect was accompanied by a decrease in recoverable enzyme and protein.
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  • 30
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    Biotechnology and Bioengineering 22 (1980), S. 337-352 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Chemostat cultures of carrot suspension cultures, where growth was limited by the concentration of phosphate in the input medium, were achieved by replacing a fixed proportion of the culture with fresh medium at daily intervals. In the range 0.05-0.30mM phosphate in the input medium and at a specific growth rate of 0.357 days-1, steady-state culture density but not anthocyanin in the cells was strictly proportional to the input phosphate concentration with no intercept. At a phosphate concentration of 0.10mM and growth rates from 0.105 to 0.430 days-1, the steady-state culture density could not be described by Monod's model of chemostat cultures, but could be described by Nyholm's model. The steady-state levels of anthocyanin were not strictly proportional to the steady-state biomass under all conditions, showing that anthocyanin production is not completely growth associated.
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  • 31
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    Biotechnology and Bioengineering 22 (1980), S. 363-376 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: White-rot fungi, which have the ability to degrade all the wood components including lignin, are of great interest in biotechnological processes based on wood and other lignocellulosic materials. It was demonstrated earlier that enough lignin can be degraded to cause a decrease in the energy demand for production of thermomechanical pulp if wood chips are pretreated by cellulaseless mutants of white-rot fungi. This paper concerns the growth conditions in wood for three white-rot fungi and their cellulaseless mutants in order to determine optimal conditions for such pretreatment processes. The pH and temperature optima have been determined as well as the growth rate in wood. The results show that the growth rate in wood. at least for Cel 44 (a cellulaseless mutant of Sporotrichum pulverulentum), is not the rate-limiting step in delignification. From different mixtures of urea and NH4H2PO4 the optimal nitrogen source was determined for the mutants. The optimal C/N ratio was found to vary between 160/1 and 400/1. It is suggested that the lower the C/N ratio, the faster the growth. It was also demonstrated that both water- and acetone-extractable substances in wood supported the growth of cellulaseless mutants. When some glucose was added to the wood, the weight loss caused by Cel 44 increased. All these observations support earlier findings that lignin in wood cannot be degraded by white-rot fungi unless a more easily metabolizable carbon source is used simultaneously.
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  • 32
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    Biotechnology and Bioengineering 22 (1980), S. 377-399 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The hydrophobic interaction of β-galactosidase with Sepharose 4B substituted with 3,3′-diaminodipropylamine was studied in both batch and column experiments. The equilibrium and the binding rate constants were determined for different phosphate buffer concentrations. The equilibrium constants exhibit a hysteresis effect, i.e., desorption constants are less than adsorption constants, and the higher the ionic strength to start the desorption, the larger the effect. The rate data are not satisfactorily described by a simple reversible first-order model. The column chromatographic data are semiquantitatively described by a local equilibrium theory without axial dispersion or intraparticle diffusion.
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  • 33
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    Biotechnology and Bioengineering 22 (1980), S. 411-420 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Aspergillus awamori NRRL 4869 was cultured on the solid substrate, wheat bran, in a modified Rollacell apparatus to produce α-galactosidase and invertase. The swivel cap on the elongated bottle permits the introduction of air while the bottle rotates. Parameters of air flow rate (0.05-0.2 liter/kg/min), rpm (0.15-15 rpm), and weight of solids (150 and 300 g) were varied. At low air flow rates (0.05 liter/kg solid/min), α-galactosidase production was minimal independent of the rotation rate. At 0.15 rpm and 0.2 liter/kg solids/min air flow rate, invertase production ceased after five days; whereas α-galactosidase production continued. The modified Rollacell can be a useful apparatus for studying solid-substrate cultures.
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  • 34
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    Biotechnology and Bioengineering 22 (1980), S. 401-410 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The growth kinetics of Bacillus subtilis KYA 741, an adenine-requiring strain, was investigated under adenine-limiting conditions. The concentration of adenine (the limiting substrate for cell growth) in the culture filtrate remained constant during the stationary phase. In this phase, DNA turnover was active and the DNA content per cell was constant throughout the cultivation period. When cells were transferred to medium without adenine, the cell concentration began to decrease immediately and then reached a constant level due to the supply of adenine from lysing to growing cells. The rates of degradation of cells and DNA were both found to be 0.2 hr-1. An equation for cell growth in this pseudostationary phase was obtained by combining Contois' equation, in which the apparent saturation constant was a function of the cell concentration, with a term for cell degradation. This equation satisfactorily expressed the feature of cell growth and adenine consumption by B. subtilis KYA 741 under adenine-limiting conditions.
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  • 35
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    Biotechnology and Bioengineering 22 (1980), S. 421-450 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Candida lipolytica was cultured batchwise using n-hexadecane as the main carbon source. Biomass production, n-hexadecane consumption, oxygen consumption, and carbon dioxide evolution were measured to follow the fermentation. The consistency of the measured data was examined using integrated and instantaneous available electron and carbon balances. Values of the “true” growth yield, ηmax, and maintenance coefficient, me were estimated using three different sets of data (biomass and n-hexadecane, oxygen and biomass, and CO2 and biomass), and the results were compared with estimates obtained from literature data. Hysteresis patterns were observed in plots of specific rates of oxygen consumption and carbon dioxide evolution versus specific growth rate.
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  • 36
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    Biotechnology and Bioengineering 22 (1980), S. 451-456 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 37
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    Biotechnology and Bioengineering 22 (1980), S. 457-462 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
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  • 38
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    Biotechnology and Bioengineering 22 (1980), S. 463-471 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: NO Abstract.
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  • 39
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    Biotechnology and Bioengineering 22 (1980) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
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  • 40
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    Biotechnology and Bioengineering 22 (1980), S. 473-474 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
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  • 41
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    Biotechnology and Bioengineering 22 (1980), S. 477-493 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The gyrogen with tubes has been the object of repeated trials carried out over a period of some years. The aim of these trials was essentially to multiply BHK cells in monolayer and to reproduce the FMD virus in one operation. At the laboratory stage, the gyrogen represented three roller flasks; at the pilot stage, 100 roller flasks; and at the industrial stage, 500 flasks. Culturing cells on a glass support, is not in itself new, but the difficulty appeared when replicating the virus in order to obtain the high parameters necessary for vaccine production. Everything was accomplished so that finally the cell culture and viral multiplication could be carried out in situ in the same apparatus.
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  • 42
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    Biotechnology and Bioengineering 22 (1980), S. 495-503 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The partition of n-hexadecane in the spent growth medium of Acinetobacter sp. HOI-N was determined by measuring the increase in the relative aqueous solubility of 3H-hexadecane as compared to controls. The amount of hexadecane partitioned was proportional to the protein concentration. The specific solubility of hexadecane (nmol/mg protein) was analyzed by least-squares fitting yielding an average slope of 0.6 with a standard deviation of 0.3, indicating either nonequilibrium of hexadecane or physical aggregation of protein. The amount of hexadecane partitioned was concentration dependent yielding optically clear microemulsions at hexadecane concentrations of less than 1.4mM and macroemulsions at hexadecane concentrations of 1.4mM or greater. Preliminary results indicated that hexadecane and partitioned by a lipoprotein complex.
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  • 43
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    Biotechnology and Bioengineering 22 (1980), S. 505-518 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effect of temperature and pH on kinetic behavior of α-galactosidase of Mortierella vinacea was investigated on the hydrolysis of p-nitrophenyl-α-D-galactopyranoside (PNPG). A very unusual kinetic behavior was observed for the soluble α-galactosidase i.e., substrate inhibition diminished gradually with increasing temperature or near the neutral pH range, and the kinetics approached the ordinary Michaelis-Menten (MM) type. On the other hand, with decreasing temperature or in acidic pH range, substrate inhibition was accelerated. Therefore, Arrhenius plots based on the initial reaction rate did not give straight lines. Furthermore, the slope in the Arrhenius plot changed with substrate concentration, which would make the determination of a characteristic value using conventional methods meaningless. However, the Arrhenius plots of individual kinetic parameters in the rate equation resulted in straight lines in the temperature range 15 to 50°C. From this, the drastic change in kinetic behavior could be explained in connection with the temperature and pH dependence of kinetic parameters in the model. For mold pellets (whole-cell enzyme), however, the influence of temperature and pH was less apparent than that of soluble enzyme because of the limitation in intraparticle diffusion. By using the rate equation that was determined for soluble enzyme and the theoretically derived effectiveness factor, the overall reaction rate for mold pellets at various temperature and pH could be predicted to some extent.
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  • 44
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    Keywords: Chemistry ; Biochemistry and Biotechnology
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    Notes: The hemicellulose fraction of ryegrass straw was extracted with NaOH and used for the production of glucose isomerase by Streptomyces flavogriseus. The level of hemicellulose extracted increased proportionately with increasing NaOH concentration up to about 4%, then the rate of increase slowed down. Hemicellulose extraction was facilitated by the combined application of heat and NaOH. Approximately 15% hemicellulose (12% as pentosan) could be obtained by treating straw with 4% NaOH for either 3 hr at 90°C or 24 hr at room temperature. The highest level (3.04 units/ml culture) of intracellular glucose isomerase was obtained when the organism was grown at 30°C for two days on 2% straw hemicellulose. The organism also produced a high yield of glucose isomerase on xylose or xylan. The NaOH-treated straw residue, after removal of hemicellulose, had approximately 75% higher digestibility and 20% higher feed efficiency for weanling meadow voles than untreated straw. Thus, the residue could be used as animal feed. A process for the production of glucose isomerase and animal feed from ryegrass straw was also proposed.
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  • 45
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    Biotechnology and Bioengineering 22 (1980), S. 543-553 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In this investigation, the activation energies of the hydrolysis of N-(α)-benzol-L-arginine ethyl ester (BAEE) and casein have been determined using trypsin immobilized on molecular sieve type 4A. There is a complete absence of intraparticle diffusion in the system, and the temperature dependence of the reaction has been studied only under external diffusional limitation. While the hydrolysis of BAEE by bound trypsin in found to be controlled by external diffusion, that of casein is kinetically controlled.
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  • 46
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    Biotechnology and Bioengineering 22 (1980), S. 533-541 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Raffinose was converted enzymatically in a hollow-fiber reactor to melibiose, sucrose, galactose, glucose and fructose. The enzymes were a crude extract of α-galactosidase and invertase produced by Aspergillus awamori NRRL 4869 on a solid substrate, Wheat bran. With a concentration of raffinose, C0, entering the reactor at a flow rate Q, and with C being the concentration of raffinose exiting the reactor, the conversion (C/C0), was studied as a function of Q at two level of C0. The data could be fairly well fitted using the analysis of Waterland et al. even though a mixed crude enzyme system was being investigated. It was found empirically that In (C/C0) was linear in Q-1, with the absolute value of the slope decreasing with increasing C0. The linearity of such plots were predicted by Lewis and Middleman from Waterland et al. for a single enzyme system obeying first-order kinetics, the slope being independent of C0. Although the assumptions involved in this approximate analytical solution are not valid, the observed linearity of the In (C/C0) vs. Q-1 plots is excellent and should prove useful in reactor design considerations.
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  • 47
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    Biotechnology and Bioengineering 22 (1980), S. 555-570 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The progesterone 11α-hydroxylase of Rhizopus nigricans ATCC 6227b is an inducible enzyme system that is primarily induced by its substrate progesterone. Maximum induction was found at a progesterone concentration of 0.5 g/liter or above. Oxygen is the other substrate for the hydroxylation and this was found to have a major effect on the amounts of hydroxylase synthesized. Optimum induction of the hydroxylase in a fermentation with a 3.1 m/sec impeller tip speed was found to occur at a dissolved oxygen tension (DOT) of 10% of air saturation. The agitation rate also effects the amount of hydroxylase synthesized with an apparent maximum at 3.1 m/sec impeller tip speed. The DOT for a maximum hydroxylation rate was much higher than for enzyme synthesis so that it was preferable to increase the DOT after induction was completed.
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  • 48
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    Biotechnology and Bioengineering 22 (1980), S. 571-595 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In a system where yeast cells grow on n-alkanes dissolved in oil drops suspended in water, the dispersed oil phase will, in most cases, be fully segregated. This means that each drop has its own history that depends on its degree of saturation with yeast cells. This degree of saturation with yeast cells is determined by a stochastic process depending on adsorption, desorption, and cell production. Although many authors mention segregation as a phenomenon likely to occur, so far this segregation has hardly been taken into account. In this paper the interaction of the population of completely segregated oil drops with the population of yeast cells, which results in growth, is described. The consequences of the model are elucidated by the discussion of some extreme cases. The batch fermentation of hydrocarbons by yeast cell is simulated by means of a Monte Carlo procedure. Adsorption, desorption, and production of yeast cells are considered as chance processes. The history of all individual drops is recorder. The influence of the chance of desorption appears to be much larger than that of the chance of adsorption (at the investigated range). Also the size of the inoculum at the start of the process appears to have a strong influence on the course of fermentation.
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  • 49
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    Biotechnology and Bioengineering 22 (1980), S. 615-637 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In this paper the results of the Monte Carlo simulations as described in an earlier paper are compared with those of batch experiments. A number of batch experiments were carried out at a low inoculation rate so that only a fraction of the oil drops were inoculated. Under these conditions the effect of the segregation of the oil phase is more clearly demonstrated. Special attention is paid to the preparation of actively growing yeast cells with which the cultures is inoculated. Also a method is developed to estimate the amount of actively growing cells with which the culture is inoculated. The other parameters necessary for the Monte Carlo simulation are measured in separate experiments: the maximum growth rate of the cells, oil drop size, and the drop parameters. Finally the growth curves (measured in the batch experiments) are compared with those calculated with the Monte Carlo procedure. A good agreement is found.
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  • 50
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    Biotechnology and Bioengineering 22 (1980), S. 597-613 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In the stochastic as well as in other models that describe the growth of yeast on liquid hydrocarbons, the adsorption and desorption of cells to drops influence to a very great extent the growth rate of the cells. In this paper a method is presented and equipment is described by which it was possible to measure the cell-drop interaction directly. While analyzing the results of these measurements it was found that the adsorption and desorption of cells are rather complicated processes. The size distribution of the oil drops is one of the parameters that has to be taken into account. The analysis of the results yields a fairly accurate value for the initial adsorption rate. Departing from a somewhat speculative description of the influence of drop size distribution on the adsorption rate, the order of magnitude of the desorption rate constant could be calculated.
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    Biotechnology and Bioengineering 22 (1980), S. 639-642 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
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    Biotechnology and Bioengineering 22 (1980), S. 643-649 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
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    Biotechnology and Bioengineering 22 (1980), S. 655-659 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
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    Biotechnology and Bioengineering 22 (1980), S. 651-654 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
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    Biotechnology and Bioengineering 22 (1980), S. 661-665 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
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    Biotechnology and Bioengineering 22 (1980), S. 677-679 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
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    Biotechnology and Bioengineering 22 (1980), S. 681-687 
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    Biotechnology and Bioengineering 22 (1980), S. 667-676 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
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    Biotechnology and Bioengineering 22 (1980), S. 693-696 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
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    Biotechnology and Bioengineering 22 (1980) 
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    Biotechnology and Bioengineering 22 (1980), S. 689-692 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
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    Biotechnology and Bioengineering 22 (1980), S. 699-734 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In recent years considerable effort has been made in the Netherlands toward the development of a more sophisticated anaerobic treatment process, suitable for treating low a strength wastes and for applications at liquid detention times of 3-4 hr. The efforts have resulted in new type of upflow anaerobic sludge blanket (UASB) process, which in recent 6 m3 pilot-plant experiments has shown to be capable of handling organic space loads of 15-40 kg chemical oxygen demand (COD)·m-3/day at 3-8 hr liquid detention times. In the first 200 m3 full-scale plant of the UASB concept, organic space loadings of up to 16 kg COD·m-3/day could be treated satisfactorily at a detention times of 4 hr, using sugar beet waste as feed. The main results obtained with the process in the laboratory as well as in 6 m3 pilot plant and 200 m3 full-scale experiments are presented and evaluated in this paper. Special attention is given to the main operating characteristics of the UASB reactor concept. Moreover, some preliminary results are presented of laboratory experiments concerning the use of the USB reactor concept for denitrification as well as for the acid formation step in anaerobic treatment. For both purposes the process looks feasible because very satisfactory results with respect to denitrification and acid formation can be achieved at very high hydraulic loads (12 day-1) and high organic loading rates, i.e., 20 kg COD·m-3/day in the denitrification and 60-80 kg COD·m-3/day in the acid formation experiments.
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    Biotechnology and Bioengineering 22 (1980), S. 757-777 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Crude extract from sweet sorghum supplemented with vetch juice was utilized as the carbohydrate source for fermentative production of lactic acid. Fermentation of media containing 7%(w/v) total sugar was complex completed in 60-80 hr by Lactobacillus plantarum, product yield averaging 85%. Maximum acid production rates were dependent on pH, initial substrate distribution, and concentration, the rates varying from 2 to 5 g(liter·hr.) The lactic acid yield was lowered to 67% under limited medium supplementation. The fermented ammoniated product contained over eight times as much equivalent crude protein (N × 6.25) as the original medium. Unstructured kinetic models were developed for cell growth, lactic acid formation, and substrate consumption in batch fermentation. With the provision of experimentally determined kinetic parameters, the proposed models accurately the fermentation process.
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    Biotechnology and Bioengineering 22 (1980), S. 779-797 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A theoretical method for predicting the elution profile of a pulse response in an immobilized-enzyme column is proposed. The method is based on a mass balance model, which is extensively used in gel chromatography. To test the method, a pulse of sucrose solution was applied to a column of spherical acrylamide gel in which was entrapped invertase from yeast, and it was eluted with 0.05M acetate buffer at pH 5.0. The elution curves of the substrate and the product were in fairly good agreement with the theoretically calculated ones. The method was extended to the system of reversible as well consecutive reactions.
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  • 65
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    Biotechnology and Bioengineering 22 (1980), S. 735-756 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Penicillin acylase has been immobilized to carboxymethylcellulose and to the resin Amberlite XAD7. The reaction kinetics of the enzyme were affected by both intrinsic (molecular) and microenvironmental effects. The Michaelis constant for the enzyme increased after immobilization as a result of an intrinsic effect of the reagent, glutaraldehyde, used for enzyme immobilization. Microenvironmental effects were of two types: diffusional limitation of access of substrate and a reaction-generated pH depression in the support particles. This depression of internal pH was observed in all the preparations and could be reduced by addition of pH buffering salts to reactor. An adsorbed pH-indicating dyc was used to determine the surface and internal pH of particles of XAD7-penicillin acylase under various reaction conditions. The extent of diffusional rate limitation in XAD7-penicillin acylase was related to the penetration depth of protein into the porous support particles. The penetration depth of protein and thus the diffusional limitation of the reaction rate could be controlled by the conditions of preparation of the immobilized enzyme. A staining technique was used to observe the location of the protein.
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  • 66
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    Biotechnology and Bioengineering 22 (1980), S. 799-820 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In this work, earlier published work on the development and investigation of fermentors with various contacting arrangements is reviewed. Methods and results of investigations on optimal construction of contacting plates are presented, and mass transfer and other characteristics of the performance of the equipment are discussed. Comparative estimates of various methods of determining mass transfer coefficients are presented. The construction and basic operating characteristics of several column fermentors with various contacting arrangements are described.
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  • 67
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    Biotechnology and Bioengineering 22 (1980), S. 821-831 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Trichoderma QM 9414 was aerobically grown on glucose as the sole carbon and energy sources in a chemostat culture. The specific rates of glucose consumption (QG), oxygen consumption (QO2), and carbon dioxide production (QCO2) at the steady state were measured to estimate the growth and maintenance requirements. From the results it was estimated that 2 mol adenosine triphosphate (ATP) were produced when1 mol NADH was oxidized through the respiratory chain of this microorganism. The true growth yield for ATP (YATP) and specific ATP consumption rate for maintenance (QATPm) calculated with this value were 0.0106 g dry cell/mmol ATP and 5.2 mmol ATP/g dry cell/hr, respectively. Using the relationships between specific growth rate (μ) and (QCO2) and between μ and QG obtained from chemostat-culture data, cell and glucose concentration histories were estimated from the carbon dioxide production rate during the batch culture. The estimated cell concentrations agreed with the experimentally measured values. Glucose concentration were slightly overestimated.
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  • 68
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    Biotechnology and Bioengineering 22 (1980), S. 833-845 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Actinoplanes missouriensis produces an intracellular soluble glucose Isomerase. The soluble enzyme can be purified by a DEAE-cellulose beads columm with a onestep salt elution. The purified enyzme exhibited a molecular weight of approximately 80,000 daltons, being composed of two identical subunits of about 42,000 daltons each. The Km for glucose is 1.33M, the Km for frucotse is 1.67M. The enzyme has an optimal pH of 7.0. The presence of the cobalt ion is not required to produce optimal activity of the enzyme if the proper amount of magnesium is present.
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  • 69
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    Biotechnology and Bioengineering 22 (1980), S. 847-857 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A methanogenic population was immobilized onto agar gel, polyacrylamide gel, and collagen membrane. Agar-gel-entrapped methanogenic microorganisms gave the highest activity. The optimum agar concentration was between 1.5 and 3% (w/v), and the optimum microbial content was 20 mg wet cells/g gel. The optimum conditions for methane production by immobilized whole cells were pH 7.0-7.5 and 37-45°C. The rate of methane production was initially 1.8 μmol/g gel/hr. Methane productivity was gradually increased and reached a steady state (4.5μmol/g gel/hr) after 25 days of incubation. The immobilized methanogenic microbial population continuously evolved methane over a 90 day period. No difference in methane productivity was observed after three months of storage at 5°C. Methane was also produced by immobilized whole cells under aerobic conditions. Furthermore, carbohydrates, such as glucose, in wastewater completely decomposed by immobilized whole cells.
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  • 70
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    Biotechnology and Bioengineering 22 (1980), S. 859-873 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Various biomass (X), product (P), and substrate (S) rate equations are considered in order to synthesize a general xanthan fermentation model from literature data. Analytical forms that provide reasonable descriptions for the X, P, and S behaviors reported by Moraine and Rogovin are shown to be the logistic equation, the Luedeking-Piret equation a modified Luedeking-Piret equation, respectively. The autonomous logistic equation allows the serial evaluation of parameters for all thee equations, rather than a simultaneous determination required by nonautonomous models.
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    Biotechnology and Bioengineering 22 (1980), S. 885-896 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Waste mycelia of Aspergillus niger from a citric acid production plant are simply treated with boiling 30-40% NaOH aqueous solutions for 4-6 hr to obtain the insoluble chitosan-glucan complex whose infrared, ESR, and x-ray diffraction spectra are reported. A number of transition- and post-transition-metal are chelated and collected by chitosan-glucan with higher yields than by animal chitosan. Immediate flocculation occur upon mixing chitosan-glucan dispersions with alginate and polymolybdate solutions. Membranes are also obtained from chitosan-glucan dispersions in acetic acid or in chloral and dimethyl formamide mixtures.
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    Biotechnology and Bioengineering 22 (1980), S. 897-912 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A scheme for lysine biosynthesis using variants of the Brevibacterium flavum intermediary metabolite synthesis is discussed. The main precursor of lysine that we are concerned with here is oxalacetate, which can be synthesized through the TCA or glyoxylate cycles or by carboxylation of PEP. Material energy balances for the main pathways of lysine biosynthesis from glucose and acetate have been formulated. Energy consumption, in the from of ATP - PATP (number of mol ATP consumed/1 mol lysine synthesized), was calculated for the main pathways of lysine biosynthesis. Theoretical conversion yields Ypmax (g product/g substrate) were estimated. Experimental data were presented concerning the increase of Yp by means of metabolism regulation: (a) by TCA-and glyoxylate-cycle enzyme induction; (b) by maintaining PEP carboxylase activity; (c) by eliminating by-product synthesis.
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    Biotechnology and Bioengineering 22 (1980), S. 875-883 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The shear viscosities of xanthan batch fermentation broths obey a power-law relation τ = K (P)[ẏ]N(P), where the power-law parameters are functions of xanthan concentration P. within the shear rate range of 1.15 to 384.0 sec-1. Cell-free solutions prepared from these samples exhibit the same values of K and N as the corresponding cell-bearing broth. Further, in the course of the fermentation time, t, it was found that K(P) and N(P) were related by an equation of the form ln K[P(t)] = ln τ0 - N[P(t)]·ln ẏ0, leading to a dimensionless power-law equation valid over the entire fermentation: (τ/τ0) = (ẏ/ẏ0)N[P(t)]. The resulting power-low from[(τ/τ0) = [ẏ/ẏ0]N(t)] indicates that all related samples will exhibit power-low plots passing through the common point, (τ0γ0). These equations have previously been observed with other polysaccharide solution. They are also shown here to be applicable to the pullulan fermentation data of Leduy et at. The parameter K is related to polymer concentration (P) with the correlation K = A PB, where B = 1.75 ± 0.25 for xanthan solutions. With X(t), S(t), and P(t) available from paper I, the correlations of this paper (hereafter referred to as II) [K(t) = f(P)(t) and N(t) = g(K(t))] provide a predictive description of the shear viscosity evolution of polysaccharide-producing fermentation broths.
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    Biotechnology and Bioengineering 22 (1980) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
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    Biotechnology and Bioengineering 22 (1980), S. 913-918 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Biotechnology and Bioengineering 22 (1980), S. 919-928 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Trypsin was immobilized on sand using five different methods. Attempts were made to attach amino-functional groups onto sand using 3-aminopropyltriethoxysilane, hexamethylenetetramine, hexamethylenediamine, and melamine. Glutaraldehyde was used as a bifunctional agent in all the methods. Methods for the estimation of the proteolytic 1activity and protein content of immobilized trypsin were standardized. The maximum retained activity was observed for trypsin immobilized on sand via 3-aminopropytriethoxysilane and glutaraldehyde. Immobilized trypsin showed a shift in the pH optimum toward the acidic side over that of soluble trypsin in all five cases. The optimum temperature for both native and immobilized trypsin prepared by the silane-glutaraldehyde method was found to be 45°C. However, the pH and thermal stabilities of immobilized trypsin were observed to be better than that of the native enzyme.
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    Biotechnology and Bioengineering 22 (1980), S. 929-946 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The population dynamics of continuous mixed cultures with pure commensalism, commensalism plus competitive assimilation, pure mutualism, and mutualism plus competitive assimilation was disused. The population does not display oscillatory phenomena where there is a single interaction of commensalism or mutualism. Damped oscillations take place when two interactions (such commensalism and competitive assimilation or mutualism and competitive assimilation) coexist in the continuous mixed culture. The stability of these systems was discussed in detail.
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    Biotechnology and Bioengineering 22 (1980), S. 947-955 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A correlation for estimating the diffusion coefficients of protein molecules is presented. The correlation is based upon literature values of the protein diffusion coefficients and molal volumes for 143 proteins. The correlation can be used for the estimation of diffusion coefficients using only molecular weight. Accuracy is such that a linear regression on 301 proteins showed 75% of the diffusion coefficients estimated fell within 20% of the experimental values. The relationship between this correlation, the Stokes-Einstein equation, and the Wilke-Chang correlation is discussed.
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    Biotechnology and Bioengineering 22 (1980), S. 957-967 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The penetration of bovine serum albumin and penicillin acylase into Amberlite XAD7 beads was determined by staining split beads. The rates of penetration were measured and correlated with a theoretically derived equation.
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    Biotechnology and Bioengineering 22 (1980), S. 969-979 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Research into bulking in laboratory-scale activated-sludge plants are reported upon. A correlation between sludge volume index (SVI) and biopolymer content (exocellular polymer, ECP) has been determined or sludge obtained under various operating conditions and with different chemical and physical characteristics. This paper interprets that correlation. A method for ECP determination that is quicker and just as precise as the gravimetric one and which enables this parameter to be used not only to interpret bioflocculation mechanisms but also as a parameter for evaluating optimal plant operation is reported.
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    Biotechnology and Bioengineering 22 (1980), S. 981-993 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In a recent publication, a technique was outlined for measuring surface aeration rates in an agitated vessels while sparging, and it was shown that surface aeration rates fall rapidly with increasing sparge rates. That work was conducted in a 0.61 m diam vessels. The work reported here was done in a small vessel (0.22 m diam) where surface aeration has been reported to be of particular significance. In general, the results obtained in the small vessel confirmed those in the large one and in addition were generally in good agreement with those recently published elsewhere for an almost identical geometry. For typical practical power inputs and sparge rates, the rate of surface aeration was never more than 20% of the sparge rate and generally less than 5%. These results indicate that surface aeration is of considerably less importance than has generally been believed following the findings of workers who estimated its effect by comparing KLa values under unsparged conditions with those when sparging.
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    Biotechnology and Bioengineering 22 (1980), S. 1007-1014 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A postulated model of a biologically active fluidized bed is given, subject to various constraints.
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    Biotechnology and Bioengineering 22 (1980), S. 995-1006 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The possibilities of using liquefied petroleum gas (LPG) heavy ends, predominantly volatile liquid n-alkanes (a location-specific hydrocarbon feedstock) for single-cell protein (SCP) production are examined against criteria established to define potentially attractive SCP production processes. The factors discussed include the use of the heat of vaporization for fermentor cooling, the efficiency of conversion of nalkane vapors, problems of maintaining constant composition substrates when feeding volatile liquid n-alkane vapors to laboratory fermentors, the possible solvent effect of liquid n-alkanes, and the possibilities of competitive inhibition. The study confirms that mixed volatile n-alkane feedstocks will introduce major physical and biological problems for both product and process research and development. Even when the technical problems are solved, the economic question of whether a direct production route using the feedstock as the fermentation substrate or an indirect route involving the conversion of the feedstock, by chemical means, into methanol, which can then be used as the fermentation substrate, needs careful examination.
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    Biotechnology and Bioengineering 22 (1980), S. 1015-1023 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Whole cells of Bacillus sp., a bacitracin-producing bacteria, were immobilized in polyacrylamide gel. The continuous production of bacitracin by an immobilized whole-cell-containing air-bubbled reactor was examined with 0.5% peptone solution. The bacitracin productivity (28 units/ml/hr) obtained with this system was higher than that with a batch system. The effluent bacitracin concentration increased with increasing aeration rate and reached a steady-state maximum above the aeration rate of 3.0 liter/min. A high bacitracin productivity was retained for at least eight days when the gel was washed with sterilized saline at a flow rate of 250 ml/hr for 2 hr once a day. The half-life of the immobilized whole-cell system was about 10 days. Bacitracin productivity by the immobilized whole-cell reactor was higher than that by a conventional continuous fermentation process at high dilution rates.
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    Biotechnology and Bioengineering 22 (1980), S. 1025-1036 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: It has been shown that the rate of enzymatic saccharification of cellulosic materials including “pure” cellulose (Whatman CF-11 cellulose), newsprint, lignocellulose (prehydrolyzed to remove hemicelluloses), and wood can be substantially increased by simultaneous wet milling. An enhanced hydrolysis rate was sustained above that observed for ball milling: providing a more extensive saccharification. The cellulosic substrates were wet milled with a variety of grinding elements, such as sand, glass beads, and stainless-steel beads, agitated in a shaker bath. Simultaneous hydrolysis was achieved with a 2% substrate slurry in a 0.1M acetate buffer at 45°C and pH 5. The effectiveness of this process was dependent upon the lignified matrix of the cellulose microfibrils, the grinding elements, and the oscillation frequency of the shaker bath. Wet milling “pure” cellulose for 48 hr, with 3.5 mm glass beads and 200 oscillations/min (opm), yielded 1031 mg reducing sugar/g substrates (93% saccharification) as compared to 483 mg (44%) for the ball-milled sample and 253 mg (23%) for the unmilled material. With the lignified substrates stainless-steel beads (3.5 mm) were more effective than glass. For lignocellulose 529 mg sugar/g substrate (93% saccharification) could be obtained by wet milling with cellulase for 24 hr. This was about three times greater than that of the ball milled (169 mg, 30%) and 10 times greater than that of the unmilled (52 mg, 9%) substrates. The method was also effective for wood particles (60 mesh) giving 143 mg sugar/g wood (approximately 38% saccharification) in 48 hr, whereas the ball-milled sample gave only 79 mg (21%) and the unmlilled substrate 38 mg (10%). These observations can be explained on the basis of the current crystalline theory for the morphology of the cellulosic microfibrils. The advantage of wet milling and simultaneous hydrolysis apparently depends on a continuous generation of accessible sites and sustained rapid hydrolysis rate as the saccharification proceeds, where in the pretreated substrates the hydrolysis rate slow down as the active sites are reduced.
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    Biotechnology and Bioengineering 22 (1980), S. 1037-1053 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The adsorption of cellulases from Trichoderma viride was studied during the hydrolysis of newspaper. By measuring individual enzyme activities it was found that in the early stage of hydrolysis enzyme components showing CxA; were adsorbed preferentially to those showing C1A; afterwards ths situation was inverted. Electrophoretic resolution of proteins in hydrolysates showed a continuous decrease of enzyme proteins in solution, and furthermore suggested that the enzymes once adsorbed remained immobilized on the substrate (even after extensive digestion). Experiments to recover the enzyme that had remained in solution after typical hydrolysis showed a potential saving of up to 40%.
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    Biotechnology and Bioengineering 22 (1980), S. 1055-1069 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Dextransucrase from Leuconostoc mesenteroides (NRRL B-512F) was purified by ultrafiltration and gel filtration chromatography in 54% yield. The specific activity of a heart cut was 58.6 U/mg; cumulative purification of that preparation was 247-fold. Of 13 carriers surveyed, only alkylamine porous silica gave immobilization efficiencies consistently above 15 %. Immobilization to silica changed the properties of dextransucrase relatively little, the optimum pH for activity remaining at 5.2, while that for stability decreased from pH 5.5-6 to pH 5.2. In short assays, highest activities of both soluble and immobilized dextransucrase occurred at 30°C. Activation energies below that temperature were 8.6 kcal/mol for the former form and 1.7 kcal/mol for the latter. Maximum stabilization of soluble dextransucrase was attained by 5mM Ca2+.
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    Biotechnology and Bioengineering 22 (1980), S. 1071-1086 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Choline oxidase (choline: oxygen oxidoreductaserpar; was immobilized on a partially aminated polyacrylonitrile membrane. The enzyme electrode, consisting of an immobilized-enzyme membrane and an oxygen probe, was employed for the determination choline. Dissolved oxygen consumption by the enzymatic reaction was measured amperometrically. The rate assay method was used for the choline determination. The response time of the sensor was 7 sec for choline. The choline assay was done within 1 min. The choline calibration curve was linear from 0 to 0.1mM. The response was reproducible within an average relative error of 2.3% when 0.2mM choline was employed for experiments. The choline in the fermentation media was determined by the sensor. Furthermore, phospholipids in the serum were also determined with native phospholiphase D and the enzyme electrode.
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    Biotechnology and Bioengineering 22 (1980), S. 1087-1093 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Biotechnology and Bioengineering 22 (1980), S. 1095-1096 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
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  • 92
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 93
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 1107-1126 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Glucanohydrolase from Trichoderma reesei, having a molecular weight of 52,000, was evaluated for kinetic properties with respect to cellobiose. Results from this work include: (1) initial rate studies that show that glucanohydrolase hydrolyzes cellobiose by a competitive mechanism and that the product, glucose, inhibits the enzyme; (2) low-pressure aqueous liquid chromatography that shows that formation of a reversion product, cellobiose, is minor and occurs in detectable amounts only a very high (90mM) cellobiose concentrations; (3) development of an equation based on the mechanism of glucanohydrolase action as determined by initial rate kinetics, which accurately predicts the time course of cellobiose hydrolysis; (4) derivation of an initial rate expression for the combined activity of cellobiase and glucanohydrolase on cellobiose. Based on data in this paper it is shown that the difference in inhibition pattern of the two enzymes could be used for determining the contamination of one enzyme by small quantities of the other.
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  • 94
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 1143-1154 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Aspergillus niger β-xylosidase was characterized when in soluble form and when immobilized to alkylamine porous silica with glutaraldehyde and to alumina with titanium tetrachloride. Energies of activation averaged 13.4 KcaL/mol for the soluble enzyme, 9.0 Kcal/mol when immobilized to alumina, and 8.0 Kcal/mol when bound to silica. The highest activity of all forms of β-xylosidase was found near pH 3. The soluble enzyme was highly stable at pH 4, where lowest rates of decay occurred, and temperature of 65°C and below. The decay rates of alumina-bound β-xylosidase and pH 4 and equivalent temperatures were approximately 10 times as high. Michaells constants were 0.200 and 0.262mM for o-nitrophenyl-β-D-xylopyranoside with soluble and alumina-bound β-xylosidase, respectively.
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  • 95
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 1127-1142 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: β-Xylosidase from a commercial Aspergillus niger preparation was purified by differential ammonium sulfate precipitation and either gel permeation or cation exchange chromatography, giving 16-fold purification in 32% yield for the first technique or 27-fold purification in 19% yield for the second. The second method in addition almost completely removed interfering β-glucosidase activity. Enzymes prepared by this method was immobilized to 10 different carriers, but only when it was bound to alumina with TiCl4 and to alkylamine porous silica with glutaraldehyde were substantial efficiencies and stabilities achieved. With alumina, the variation of activation procedure, amount of β-xylosidase offered, and activation solution composition yielded maximum activities of over 40 U/g with approximately 70% immobilization efficiency. Variation of binding pH and incubation time led to a maximum immobilized activity of 1.3 U/g with 78% immobilization efficiency on silica.
    Additional Material: 3 Ill.
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  • 96
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 1155-1173 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Cells form the yeast Hansenula polymorpha (ATCC 26012) were successfully immobilized by entrapment in a polyacrylamide gel. The resulting gel showed high methanol oxidase activity especially after treatment with a detergent (CTAB). The enzymatic properties of the gel-entrapped cell were not very different from that of the soluble enzyme except that no inhibition was observed at high methanol concentration. In continuous reactors, the gel-entrapped cells showed a much higher stability than other enzyme preparations. The inactivation mechanism was investigated and proved to be the oxidation of essential SH group(s) of the methanol oxidase molecule by hydrogen peroxide. Treatment with β-mercaptoethanol prevented inactivation or regenerated activity.
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  • 97
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 1189-1211 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A distributed parameter model for an airlift fermentor is presented. A riser represents the airlift fermentor, with plug flow in both gas and liquid phases, a well-mixed section that acts as gas separator, and a downcomer with plug flow. The set of equations proposed makes possible both the understanding and design of the system. Macroscopic balances shows a behavior that is very close to conventional continuous stirred tank fermentor from the viewpoint of biomass production. In addition, the model predicts concentration profiles of biomass, substrate and oxygen in the liquid, and oxygen in the gas phase. This allows estimation of optimal gas flow rate for sufficient oxygen transfer with minimum energy input.
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  • 98
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 1175-1188 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An immobilized growing cell system was applied to the continuous L-isoleucine production by Serratia marcescens. In the new immobilized-cell systems using the carrageenan gel method. S. marcescens cells in the gel required nutrients and oxygen for growth, and the numbers of living cells per milliliter of gel increased to the levels of that of free cells in the liquid medium. This immobilized growing cell system exhibited high and stable activity for isoleucine production under steady-state conditions. Continuous isoleucine production was carried out by feeding the nutrient medium under aeration into a fluidized bed reactor containing the immobilized cells. In the continuous operation, an efficient production was maintained by automatically controlling the pH of the reaction mixture at 7.5. The productivity of isoleucine increased using multibed reactors. In a two-bed reactor system, the effluent L-isoleucine concentration reached 4.5 mg/ml at a retention time of 10 hr, and a steady state was maintained for longer than 30 days.
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  • 99
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 1213-1224 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effect of regular variations in the input limiting nutrient concentration at different cycle amplitudes on the growth and composition (elemental and macromolecular) of Escherichia coli ML30 in chemostat culture is described. The cycle time was maintained constant at 2.0 hr. The basal level of nutrient fed to cultures was also maintained constant but the concentration amplitude was varied over a range from 0.2 to 5.0 g/liter. A lag between the stimulus and organisms response was observed and found to be independent of cycle amplitude over most of the range examined. Increasing the cycle amplitude did not effect the cell yield from glucose or the elemental composition of the organisms. However, large variations in the macromolecular composition of the cells (on a dry weight basis) were found; at 4.0 g/liter amplitude the cells contained some 82% protein. The relevance of this type of reactor operation in large-scale fermentations is discussed.
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  • 100
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 1237-1247 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The reaction kinetics of the enzymatic of cephalexin from 7-aminodea-cetoxy cephalosporanic acid and phenylglycine methylester was studied using the synthesizing enzyme obtained from Xanthomonas citri. The activation energy, Km value for 7-aminodeacetoxy cephalosporanic acid and phenylglycine methylester, and Ki value for phenylglycine methylester were determined as 8.63 kcal/mol, 3.7mM, 14.5mM, and 70mM, respectively. The enzyme was found to be constitutive and susceptible to deactivation.
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