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  • 1
    Electronic Resource
    Electronic Resource
    Dense growth of aerobic bacteria in a bench-scale fermentor (1976)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 81-94 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Escherichia coli B, Escherichia coli MRE 600, Escherichia coli K 12-3300, Pseudomonas fluorescens, and Aerobacter aerogenes were grown exponentially in a bench-scale fermentor to cell concentrations in the range of 20 to 41 g dry cells/liter at 30°C and 30 to 55 g dry cells/liter at 25°C. The high cell concentrations were achieved in a growth system previously described for growth of Escherichia coli W (Biotechnol. Bioeng., 16, 933 (1974); ibid. 17, 227 (1975)). Various enzyme activity levels in the high-concentration cells were compared to those in cells grown in conventional low-density cultures. No significant differences were found. The culture supernatants were found to be essentially free of high-molecular weight metabolic or cell lysis products. Yield constants for glucose, nitrogen, oxygen, and phosphorus were also determined in the dense cultures and some of their relations to the growth conditions are discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260180107
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  • 2
    Electronic Resource
    Electronic Resource
    Pilot scale exponential growth of Escherichia coli W to high cell concentration with temperature variation (1976)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 839-846 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An efficient method to grow Escherichia coli W to high cell concentrations on the pilot scale is described and discussed. The method involves growth linked introduction of glucose; and ammonia to the culture, sparing with oxygen, and maintenance of aerobic conditions by gradually decreasing the temperature in the culture in order to keep the oxygen demand within the limits of the capacity of supply. Under these conditions the linear rate of cell mass production is actually the result of exponential growth with a gradually decreasing growth-rate constant.About 10 kg packed cells were produced in a 50 liter working-volume fermentor in one run of 13 hr. The concentration of the cells at the end of the growth was about 47 g dry cells/liter. The expenditure for nutrients was minimal and the controls were of simple automatic nature. From the determined yield constants for glucose, nitrogen, phosphorus, and oxygen it may be inferred that the cells grown by this method are similar to those grown exponentially at constant temperature.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260180606
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  • 3
    Electronic Resource
    Electronic Resource
    Growth of E. Coli W to high cell concentration by oxygen level linked control of carbon source concentration (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 23 (1981), S. 1015-1021 
    Details
    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 of E. coli W in a bench scale fermentor to high cell concentration is described. The method involves growth-linked introduction of ammonia to the culture, sparging the culture with oxygen, and maintenance of aerobic conditions during the final growth phase by gradually and automatically decreasing the concentration of the carbon source, sucrose, in the culture. Thus, the oxygen demand is kept within the limits of the supply capacity, and a linear growth rate during the final phase of growth is obtained. A concentration of 42 g dry cell per liter was obtained. The yield constants for nitrogen and phosphorous were determined and were compared with those obtained using the temperature variation method.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260230509
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis and Structure of Tetraaryl Orthocarbonates from carbonimidic acid esters (1992)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 334 (1992), S. 95-97 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19923340120
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  • 5
    Electronic Resource
    Electronic Resource
    Non-steroidal anti-inflammatory agents. Part 23. Synthesis and Pharmacological Activity of Enaminones which inhibit both bovine cyclooxygenase and 5-lipoxygenase (1998)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 340 (1998), S. 256-263 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and stereochemical characteristics of pyrrolidino-, isoquinolino- and indolo-enaminones 2-11 are reported. The inhibition of cyclooxygenase was determined in a bovine thrombocyte intact cell assay and that of 5-lipoxygenase using intact bovine polymorphonuclear leucocytes. Except compound 2c′ which is a well-balanced dual inhibitor of both enzymes, all other enaminone derivatives are weak inhibitors of both cyclooxygenase and 5-lipoxygenase. Structure-activity relationships of the enaminones in relation to known anti-inflammatory drugs are discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19983400309
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  • 6
    Electronic Resource
    Electronic Resource
    Azobenzene-Based Photoswitchable Catenanes (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 649-656 
    Details
    ISSN: 0947-3440
    Keywords: Catenanes ; Interlocked rings ; Mechanical bond ; Photoswitches ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four catenanes (1-4) and the corresponding tetracationic monocycles 5-8 are synthesized. X-ray structural analyses allow a prediction of the mobility (circumrotation) of the „interlocked“ rings in the catenanes, which is proven by 1H-NMR spectroscopy. An unexpected order in the crystal packing of 6 is demonstrated. (E/Z) isomerization in one ring influences the second ring of 1-4 and inversely. An existing obstacle inside the cavity of the switchable macrocycle can block this isomerization completely.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199519950491
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  • 7
    Electronic Resource
    Electronic Resource
    Fluid-mechanical forces in agitated bioreactors reduce the CD13 and CD33 surface protein content of HL60 cells (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 41 (1993), S. 868-877 
    Details
    ISSN: 0006-3592
    Keywords: surface proteins ; hydrodynamic injury ; HL60 cells ; Pluronic F68 ; flow cytometry ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Flow cytometry was used to examine the effect of hydrodynamic forces in surface aerated stirred tank bioreactors on the quantity of CD13 and CD33 surface proteins of Hl60 (human promyelocytic leukemia) cells. A step increase in agitation of the 2-L bioreactors from 80 to 400 rpm reduced the apparent growth rate and the average CD13 and CD33 content per HL60 cell. The effects on the two surface proteins were observed within 30-60 min following the increase in the agitation and preceded observed effects on cell growth by at least 10 h. Upon reduction of the agitation rate back to 80 rpm, the CD13 and CD33 content recovered (in ca. 10 h) for CD13 and ca. 29h for (CD33) to the levels of the control culture whose agitation rate was maintained at 80rpm. The CD13 and CD33 cell content was reduced even at agitation rates (270 rpm) that did not affect cell proliferation. Pluronic F68 (a commonly used shear protectant) had a protective effect on the CD33 content per cell of cultures subjected to hydrodynamic injury but no effect on the CD13 cell content. Possible bioprocessing and physiological implications of these findings are discussed © 1993 Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260410906
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  • 8
    Electronic Resource
    Electronic Resource
    Determination of antibody content in live versus dead hybridoma cells: Analysis of antibody production in osmotically stressed cultures (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 40 (1992), S. 947-964 
    Details
    ISSN: 0006-3592
    Keywords: hybridoma cells ; antibody production ; flow cytometry ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Hybridomas are known to exhibit increased specific antibody production rated when subjected to environmental stress. Under these conditions, viability is low so that population-average measurements do not properly reflect the state of viable cells. Even for flow cytometry, which gives a population distribution, special techniques must be used to discriminate between viable and nonviable cells. We describe the use of the vital stain ethidium monoazide (EMA) for independent measurement of intracellular antibody content in live and dead cells via flow cytometry. EMA is shown to be superior to light scattering techniques in identifying dead cells. We apply this technique to show that, in control batch culture, the specific antibody prodution rate and antibody content in live cells are constant during exponential growth, but decrease as cells enter the stationary phase. Antibody is retained in dead cells, but at a lower level than in live cells. We further show that, under hyperosmotic stress, the specific antibody production rate and antibody content in live both remain high during death phase. © 1992 John Wiley & Sons, Inc.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260400811
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  • 9
    Electronic Resource
    Electronic Resource
    Damaging agitation intensities increase DNA synthesis rate and alter cell-cycle phase distributions of CHO cells (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 40 (1992), S. 978-990 
    Details
    ISSN: 0006-3592
    Keywords: DNA synthesis rate ; agitation ; cell-cycle kinetics ; flow cytometry ; cell culture ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of fluid-mechanical force (agitation) on the cell cycle kinetics of Chinese hamster ovary (CHO) cells cultured in suspension in 2-L bioreactors has been examined. A two-color flow cytometry method was used to determine the fraction rate of DNA synthesis. With increased agitation intensity, cell viability decreased as a result of increased cell death. However, increased agitation induced the viable cells of the culture to a higher proliferative state relative to a control culture. The fraction of viable cells of the high-agitation culture (250 rpm) in S phase was higher (up to 45%) and in G1 phase was lower (up to 50%) compared with the viable cells of the control culture (80 rpm). The DNA synthesis rate per viable S-phase cell of the high-agitation culture was confirmed by recovery experiments, which were conducted to measure the apparent specific growth rate and the cell cycle kinetics of the high-agitation culture upon reduction in the agitation rate from 250 rpm back to 80 rpm. The apparent specific growth rate of the test culture, calculated for the first 12 h of the recovery period, was greater than the apparent specific growth rate of the control culture. Furthermore, the proliferative state of the viable cells of the test culture, which had become higher relative to the control culture during the high agitation period, gradually approached the level of the control culture during recovery. Results also show that the magnitude of the agitation intensity; the culture agitated at 250 rpm attained a greater proliferative state than a parallel culture agitated at 235 rpm. The 250-rpm culture had a higher fraction of S-phase and a lower fraction of G1-phase cells than the 235-rpm culture. The DNA sunthesis rate per viable S-phase cell of the 250-rpm culture was greater than of the 235-rpm culture. © 1992 John Wiley & Sons, Inc.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260400814
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  • 10
    Electronic Resource
    Electronic Resource
    Stereoselective bioconversions in continuously operated fixed bed reactors: Modeling and process optimization (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 52 (1996), S. 459-471 
    Details
    ISSN: 0006-3592
    Keywords: continuous kinetic resolution ; fixed bed reactors ; mathematical modeling ; lipases ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The nonaqueous lipase-catalyzed kinetic resolution of racemic 2-methyl-1-pentanol in a continuously operated fixed bed reactor was theoretically and experimentally studied. A 2-dimensional mathematical model was developed to predict the performance of the heterogeneous enantioselective biotransformation and to optimize the productivity and effective stereoselectivity of the process by taking pore diffusion, solid(SINGLEBOND)liquid mass transfer, convection, and axial dispersion into account. Experimental investigations were conducted with lipase from Pseudomonas sp. immobilized by ionic binding in the pores of the anion exchange resin Duolite A 568. As determined in prior initial rate experiments, the specific activities of the immobilized lipase were maximal at a water activity of approximately aw = 0.67 and revealed a significant dependence on the amount of enzyme bound to the carrier material, with enantiomeric ratios slightly increasing with increasing water activities. Continuous resolution processes were carried out at a wide range of enzyme loadings. By controlled immobilization according to the theoretically evaluated optimal enzyme loading, the continuous racemic resolution could be optimized to obtain (R)-2-methyl-1-pentanol at high productivity and enantiopurity (ee 〉 95%). The steady-state characteristics of the system could be generally predicted by the model, despite the necessity to reevaluate the kinetic properties of the immobilized lipase to account for the complex non-aqueous microkinetics in a heterogeneous environment. Further model extension introducing competitive inhibition of free water in solutions as well as water diffusion and adsorption to the biocatalyst were useful in providing a more accurate description of the experimental results. © 1996 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
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