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  • Biochemistry and Biotechnology  (9)
  • Wiley-Blackwell  (9)
  • Wiley
  • 1
    Electronic Resource
    Electronic Resource
    Hydrolysis of triglyceride by solid phase lipolytic enzymes of Rhizopus arrhizus in continuous reactor systems (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 23 (1981), S. 1703-1719 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Continuous hydrolysis of triglyceride in organic solvent systems using Rhizopus arrhizus mycelia as a source of insolubilized lipase has been studied in packed-bed and stirred-tank reactors. Typically a packed bed reactor containing 1 g of mycelia fed at 1 mL/min with a solution of 2.5% (w/v) olive oil in di-isopropyl ether gave a fatty acid yield of 45% at 30°C. The optimum water concentration was found to be 0.17% (w/v) except under conditions of high oil feed concentration and high yield where no optimum was established. No temperature optimum was observed over the range 20-55°C. Calculated activation energies of 13-20 kJ/mol, depending on temperature, were lower, while Km(app) values of 0.1-0.3M were higher than those for hydrolysis in conventional aqueous emulsion systems. No evidence of any significant diffusional limitation, which could account for these values, was obtained. The mycelia showed a loss of activity of 0.6-1.0%h at 30°C. The packed bed proved markedly superior to the stirred tank for this system.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260230804
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  • 2
    Electronic Resource
    Electronic Resource
    Lipolytic activities of a lipase immobilized on six selected supporting materials (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 35 (1990), S. 132-137 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Six different types of materials including PVC, chitosan, chitin, agarose, Sepharose, and Trisacryl were evaluated for their lipase-coupling efficiencies. Among those tested, chitosan yielded the highest amount of lipase (79 mg/mL packed gel) immobilized but with lowest oil hydrolytic activity (0.03 mg eq/mL gel). The amount of lipase immobilized was affected by the length of the hydrocarbon chain attached to the PVC matrix but not by the pore size of the supports used. On the other hand, the specific activity of the immobilized lipase was affected by the pore size but not by the chain length of the hydrocarbon attached to the support. After immobilization, the optimal reaction pH was shifted from 7.5 to 8.5 and the optimal reaction temperature from 35 to 45-55°C. Lipase immobilized on PVC exhibited higher thermal stability than that on agarose. The half-life of the PVC immobilized lipase operating at 30°C in a packed-bed reactor was estimated to be about 400 h.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260350204
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  • 3
    Electronic Resource
    Electronic Resource
    Changes of lipase-catalyzed lipolytic rates in a batch reactor (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 39 (1992), S. 1128-1132 
    Details
    ISSN: 0006-3592
    Keywords: lipolytic rates ; hydrolysis ; tributyrin ; Candida rugosa ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A dramatic change of the reaction rate was observed for the lipase-catalyzed hyrolysis of tributyrin in a batch reactor. Immediately after the addition of the enzyme, the lipolysis rate increased continuously until a maximal reaction rate was reached. The duration of the induction was mainly controlled by the bulk enzyme concentration and the reactor stirring speed. The reaction rate dropped sharply after reaching its maximal value. The lipolysis decayed at a rate of about 0.012 min-1, and was not affected by changes of the stirring speed. This decay was attributed to the fast deactivation of the surface-adsorbed lipase, and possibly to the extremely slow desorption of the inactivated species. For reaction time longer than 120 minutes, the lipolysis decreased at a much slower rate. Several mechanisms for the decay of the lipolysis rate were discussed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260391108
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  • 4
    Electronic Resource
    Electronic Resource
    Enhancing effect of albumin hydrolysate on ethanol production employing Saccharomyces sake (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 45 (1995), S. 450-453 
    Details
    ISSN: 0006-3592
    Keywords: ethanol production ; albumin hydrolysate ; plasma membrane ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The enhancing effect of albumin hydrolysate on ethanol production was investigated in ethanol fermentations using Saccharomyces sake. In batchwise ethanol production, addition of supplemental albumin hydrolysate and phosphatidylcholine, or albumin hydrolysate alone, brought about a more than 60% increase in final ethanol concentration (148 or 144 g/L compared with 88 g/L with no supplementation [control] after 72 h). The effect of the supplements is believed to be due to an enhanced alcohol tolerance of cells grown in media containing the supplements. Cells grown in media containing albumin hydrolysate were enriched in phenyalanine, tyrosine, and methionine in their plasma membranes. All three amino acids were also present in considerable amounts in the albumin hydrolysate. This fact suggests that the three amino acids, which are present in albumin hydrolysate, are incorporated into the plasma membranes of cells. Under ethanol production conditions in which only one amino acid among the components of albumin hydrolysate was excluded, namely phenlalanine, tyrosine, or methionine, significant reductions in ethanol production resulted. © 1995 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260450510
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  • 5
    Electronic Resource
    Electronic Resource
    Preparation of various glucose esters via lipase-catalyzed hydrolysis of glucose pentaacetate (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 29 (1987), S. 648-651 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: β-D(+)-Glucose pentaacetate was hydrolyzed both chemically and enzymatically. In contrast to the alkaline hydrolysis, esterase-catalyzed deacetylations afforded significant accumulation of intermediate glucose esters at different degrees of substrate conversion. Aspergillus niger lipase, the most suitable of the four enzymes tested, was used for preparative hydrolysis of glucose pentaacetate. As a result, gram quantities of pure glucose-2,3,4,6-tetraacetate, glucose triacetate (a mixture of two positional isomers, 2,4,6- and 3,4,6-), and glucose-4,6-diacetate were prepared.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260290515
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  • 6
    Electronic Resource
    Electronic Resource
    Measurement of hydrodynamic shear by using a dissolved oxygen probe (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 41 (1993), S. 296-302 
    Details
    ISSN: 0006-3592
    Keywords: shear measurement ; cell culture reactors ; dissolved oxygen probe ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: When a dissolved oxygen (DO) probe is submerged in an air-saturated cell culture medium the thickness of the liquid film that exists outside the membrane of a DO probe changes with hydrodynamic shear. The response of the DO probe thus varies with the hydrodynamic shear environment near the DO probe in cell culture reactors. The thickness of the liquid film was estimated by using a three-layer model, which describes the flow of DO molecules through the liquid layer, the membrane, and the electrolyte, to the cathode of a DO probe. According to the three-layer model, the current output of the DO probe was a strong function of thickness of the liquid film outside the membrane of the DO probe. A correlation between shear rates on the surface of the probe and the DO saturation reading was obtained by using two concentric cylinders with a rotating inner cylinder. This correlation was then used to characterize the local hydrodynamic shear environment in a cell culture reactor. © 1993 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260410303
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  • 7
    Electronic Resource
    Electronic Resource
    Lipase-catalyzed oil hydrolysis in the absence of added emulsifier (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 31 (1988), S. 628-633 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260310618
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  • 8
    Electronic Resource
    Electronic Resource
    Dissociation and electrophoretic separation of dextranase and dextranase inhibitor from a tighly bound enzymeinhibitor complex of Streptococcus sobrinus (1993)
    Weinheim : Wiley-Blackwell
    Electrophoresis 14 (1993), S. 613-618 
    Details
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Endodextranase was separated from dextranase inhibitor in culture filtrates of Streptococcus sobrinus by sodium dodecyl sulphate-polylamide gel electrophoresis (SDS-PAGE) in gel slabs containing blue dextran. Sample preparation included dissociation of the enzyme from its inhibitor by boiling for 1 min in SDS. During subsequent incubation of the gel, dextranase was located as clear bands on a blue background, and dextranase inhibitor appeared as blue zones on a clear background following incubation in dextranase solution. The enzyme and the inhibitor existed in multiple forms, and the range of molecular masses for dextranase (223-132 kDa) permitted an excellent separation from dextranase inhibitor (49-25 kDa). Although dextranase-negative mutants, and wild type strains grown at low dilution rate in the chemostat, were devoid of free dextranase activity, the enzyme was easily located by analytical SDS-PAGE. Likewise, analysis of filtrates from wild type strains, which contained no free inhibitor activity when growth occurred at high dilution rate, revealed dextranase inhibitor activity on the gels. The total production (free + combined) of dextranase and inhibitor by S. sobrinus was determined by dissociation of enzyme-inhibitor complexes in concentrated cell-free filtrates, their separation by preparative SDS-PAGE and electroelution from the gels, followed by renaturation of protein activity. From a comparison of activity tests of free dextranase and free inhibitor in untreated filtrates with the results of similar tests on renatured electroeluates, the proportion of each constituent bound into a complex under each growth condition could be deduced.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150140196
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  • 9
    Electronic Resource
    Electronic Resource
    Characterisation of basic proteins from Spiroplasma melliferum using novel immobilised pH gradients (1997)
    Weinheim : Wiley-Blackwell
    Electrophoresis 18 (1997), S. 1393-1398 
    Details
    ISSN: 0173-0835
    Keywords: Two-dimensional polyacrvlamide gel electrophoresis ; Proteome ; Spiroplasma melliferum ; Mollicutes ; Functional proteome ; Protein microsequencing ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) has become the method of choice for efficient separation of complex protein mixtures. Previously, analysis of the Spiroplasma melliferum proteome (protein complement of a genome) has been performed with pH 3-10 and narrow range pH 4-7 IPG gel strips. We report here on the use of novel 18 cm basic (pH 6-11) immobilised pH gradients (IPG) to increase the resolution of protein spots visible within 2-D gels. These gradients were synthesised to emulate the gradient of commercially available IPG gel strips in a 5 cm region of overlap so as to attempt construction of a more complete map of cellular protein expression. Approximately 50 additional gene products were detected from S. melliferum that were not previously well-resolved or visible using wide-range pH 3-10 IPG gel strips. Twenty-seven of these were electrotransferred to polyvinylidene difluoride (PVDF) membrane and analysed by N-terminal protein microsequencing. Protein spots with an initial peak yield of as little as 100 femtomoles (fm) were sequenced to 5-10 amino acid residues, demonstrating the importance of improved sample handling procedures and analytical technologies. Many essential metabolic enzymes were shown to have basic pI, including: glyceraldehyde-3-phosphate dehydrogenase, pyruvate kinase, carbamate kinase and lactate dehydrogenase. A very basic protein (pI ≍ 11.0) was identified as uridylate kinase, an enzyme indirectly associated with pyrimidine biosynthesis and thought be absent in some members of the bacterial class Mollicutes. The advent of novel basic (pH 6-11) IPGs has allowed the visualisation of a significantly greater percentage of the ‘functional proteome’, that portion of the total protein complement of a genome actively translated within a specific time frame, on 2-D electrophoresis gels. This will aid in the characterisation of translated gene products in conjunction with genome sequencing initiatives.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150180814
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