摘要:

AbstractSince a stable alcohol oxidase with a high specific activity is not commercially available, we propose to produce and purify this enzyme from a strain of the yeastHansenula polymorpha. This alcohol oxidase was immobilized into a gelatin matrix and its activity was estimated by a pO2sensor. The enzyme electrode obtained was then used in a continuous flow system to measure methanol or ethanol concentrations. The sample oxygen content dependence of the signal was minimized by the support properties. Measuring time for each sample were less than two minutes including response data treatment and rinsing step. The enzyme electrode response was set for ethanol from 0.5mMto 15mMand for methanol from 10mMto 300mM. On repeated use, the electrode signal for 10mMof ethanol was stable for at least 500 assays. Analysis have been performed in different beverages such as wine and beer, and the results compared to those obtained with classical methods of analysis.

ISSN:0006-3592    

DOI:10.1002/bit.260300902

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractIt is known from the literature that two microbial populations competing purely and simply for a common substrate in a spatially inhomogeneous environment may under certain conditions coexist in a steady state. This paper studies pure and simple competition between two microbial species in three alternate configurations of two interconnected ideal chemostats and focuses on the effects of the operating parameters‐dilution rate, substrate concentration in the feed to the vessels, recycle ratio, and volume ratio of the two vessels, splitting ratio of the external feed to the chemostats‐on the coexistence of the two competitors. It is shown that the coexistence steady state is practically feasible in the sense that it occurs in a finite domain of the operating parameters space. Theoretical and numerical results are presented, some of them in the form of operating diagrams projected on the two‐dimensional subspace. A comparison of the three possible configurations is of

ISSN:0006-3592    

DOI:10.1002/bit.260300903

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractEnzymatic lactose hydrolysis by β‐galactosidase (lactase) was investigated with respect to the formation of oligosaccharides. An analysis of the formation of oligosaccharides and their control is important in the development of technical applications for enzymatic lactose hydrolysis. The available literature data on transfer reactions of lactase were reviewed, compared, and presented in a concise tabular form. Mechanisms and possible ways of modelling enzymatic lactose hydrolysis, including formation of oligosaccharides, are present

ISSN:0006-3592    

DOI:10.1002/bit.260300904

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractEnzymatic lactose hydrolysis using two yeast and two fungal lactases that are of current technical interest was studied. The enzymes were compared regarding their oligosaccharide production. Parameters influencing oligosaccharide formation, together with the effect of immobilization were examined and conditions minimizing oligosaccharide content in the hydrolysis product were proposed. Enzymatic whey hydrolysis was also considered. A possibility of enzymatic lactose recombination from its hydrolysis products was shown.

ISSN:0006-3592    

DOI:10.1002/bit.260300905

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractPenicillin V and/or G were extracted from fermentation broth by Amberlite LA‐2 inn‐butylacetate at pH 5 in a laboratory centrifugal extractor, Type SA 01 of Westfalia, up to an overall phase throughput rate of 30 L/h, in a bench‐scale four‐stage extraction system, consisting of Type TA 1 of Westfalia, up to an overall phase throughput rate of 110 L/h, and in a pilot‐plant three‐stage extraction unit, consisting of Type TA 7 extractors of Westfalia, up to a phase throughput rate of 990 L/h with very high degrees of extraction (up to 99%). The reextraction from the ion‐pair complex, which contained organic solvent, was performed by phosphate, borate, or carbonate buffer at pH 7.5–8.5 in all three extractor systems with degrees of extraction up to 98%, but at considerably lower overall phase throughput rates than those of the extraction, since no satisfactory phase separation is possible at higher t

ISSN:0006-3592    

DOI:10.1002/bit.260300906

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractThe influence of microheterogeneity on enzyme inactivation kinetics is presented. Examples of different enzymes are given where microheterogeneity has been detected by different techniques. The different statistical models are presented which include the influence of microheterogeneity on enzyme inactivation kinetics and stability. As the microheterogeneity of the enzyme increases, there is a sharper decline in the normalized activity during the initial stages of the deactivation but a greater stability and activity, compared to similar homogeneous enzyme, as the deactivation proceeds. Microheterogeneity makes the deactivation reaction have a higher apparent order of reaction. The implications of microheterogeneity on enzyme inactivations are high lighted by different examples. The analysis provides fresh physical insights into the chemistry, subpopulations, structure, and function of enzymes.

ISSN:0006-3592    

DOI:10.1002/bit.260300907

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260300908

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260300909

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260300910

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260300911

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY