摘要:

AbstractThe precipitation of proteins with heteropolyacids has been studied for the purpose of large scale primary purification. A precipitate will form if the pH of the reaction between purified ovalbumin, hemoglobin, trypsin, pepsin, bovine serum albumin, ovomucoid, gelatin or ribonuclease and tungstrophosphoric, tungstosilicic or molybdosilicic acid is close to the isoelectric point of the protein and does not cause the dissociation of the heteropolyacid. Below the isoelctric point, the percent precipitation depends on the conformational changes of the protein. The precipitation of ovalbumin with tungstophosphoric decreases as the ionic strength of the buffer increases and is independent, of the protein concentration. Mixtures of ovalbumin and bovine serum albumin, though having close isoelectric points, can be separated by varying the concentration of the precipitant. The electropositive groups which combine with the tungstophosphoric acid are guanidino, ε‐amino and imidazole. No precipitation is given by the α‐amino groups. Filtrates of microbial fermentations containing lactase, glucose aerode‐hydrogenase, alkaline protease, amyloglucosidase, and transglucosylase have been purified by precipitation with heteropo

ISSN:0006-3592    

DOI:10.1002/bit.260120102

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

年代:1970

数据来源: WILEY

摘要:

AbstractFungal cells fromCurvularia lunatawere entrapped in a crosslinked polyacrylamide gel. The gel‐cells obtained as granules were applied in the microbial transformation of Reichstein compound S leading to cortisol through an 11‐β‐hydroxylation step. Some kinetic studies of this conversion using gel‐cells were carried out. In addition, it was shown that gel‐cell granules which had lost part of their 11‐β‐hydroxylase activity on storage could be reactivated yielding preparations with increased activity.FromCorynebacterium simplexa steroid dehydrogenase catalyzing the Δ1‐ dehydrogenation of cortisol leading to prednisolone was isolated and partially purified. The preparation was entrapped in a crosslinked polyacrylamide gel and the gel‐enzyme granules obtained used in steroid dehyd

ISSN:0006-3592    

DOI:10.1002/bit.260120103

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

年代:1970

数据来源: WILEY

摘要:

AbstractThe kinetics of the batch‐wise liquid‐phase oxidation of ferrous sulfate by the organismThiobacillus ferrooxidanshas been studied over a range of temperatures from 20°C to 31°C and in the presence of an abundant supply of oxygen, carbon dioxide, and other nutrients.The rate of oxidation was found to be accurately described by the equation\documentclass{article}\pagestyle{empty}\begin{document}$$ \frac{{dS}}{{dt}} = \frac{{\mu _m SX}}{{Y(K + S)}} $$\end{document}wheret= time hr,S= concentration of ferrous ions g Fe++/1., μm= maximum specific growth rate of bacteria, hr−1.Y= mass of bacteria produced per gram of iron oxidized g/g,K= saturation constant, g Fe++/l., andX= concentration of bacteria g/1.The value for the maximum specific growth rate, μm, was found to vary from 0.12 hr−1at 20°C to 0.20 hr−1at 31°C, while the value for the saturation constantKvaried randomly between 1 and 2 g/1.A method has also been described which permitted evaluation of the relevant rate constants μmandKwithout direct knowledge of the bacterial population. This method was found to yield values of μmandKwhich agreed with values determined accurately by a statistical regression analysis of the

ISSN:0006-3592    

DOI:10.1002/bit.260120104

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

年代:1970

数据来源: WILEY

摘要:

AbstractA model of oxygen absorption in microbiological systems of zero order reaction rate is proposed. The partial differential equation was solved to predict the profile of the oxygen concentration boundary layer next to a gas‐liquid interface. Generally speaking, the presence of microbial cells always helps to increase the oxygen absorption rate over that of physical absorption. Only when the microbiological reaction is slow as judged by the fact that the reaction time,tr, is much larger than the diffusion time,tD, can one rightfully approximate the oxygen absorption in microbiological suspensions by physical absorptio

ISSN:0006-3592    

DOI:10.1002/bit.260120105

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

年代:1970

数据来源: WILEY

摘要:

AbstractA pilot‐plant process has been developed for the continuous extraction and partial purification of prolyl‐tRNA synthetase from mung bean. The bean slurry was wet ground in a hammer mill, clarified by two‐stage centrifugation, and the protein in the effluent fractionated by precipitation at pH values of 5.2 and 4.2. The throughput was 13 kg dry bean/hr. The improved extraction process and reduced processing time resulted in an enzyme product with a specific activity 16 × that previously obtained in the batch process. The yield was also 50–60 time

ISSN:0006-3592    

DOI:10.1002/bit.260120106

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

年代:1970

数据来源: WILEY

摘要:

AbstractXanthan biopolymer has been produced by single‐stage continuous fermentation withXanthomonas campestrisNRRL B‐1459 in a medium of glucose, minerals, distillers' solubles, and urea for as long as 20 days. At the highest dilution rate studied (D = 0.0285 hr−1), the steady state rate of xanthan production was 0.36 g/kg/hr and the steady state yield, basis glucose consumed, was 68%. Observations indicate that xanthan production rate is a function of pH

ISSN:0006-3592    

DOI:10.1002/bit.260120107

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

年代:1970

数据来源: WILEY

摘要:

AbstractGlucoamylase bound to DEAE‐cellulose in 0.05 M sodium acetate, pH 4.0, is active in the conversion of starch to glucose. The activity of the DEAE‐cellulose‐bound enzyme ranges from 16 to 55% of the activity of the free enzyme. Binding of the enzyme narrows the pH optimum to approximately 4.0 and lowers the temperature optimum to 40–50°C as compared to a 60°C temperature optimum for the free enzyme. Concentrations of acetate buffer above 0.1Mdisrupt the DEAE‐cellulose‐enzyme complex. Columns were used with some success for the continuous conversion of starch. Pretreatment of the starch with α‐amylase and clarification were necessary to prevent blocking of the column. Columns maintained activity for more than 3 weeks of cont

ISSN:0006-3592    

DOI:10.1002/bit.260120108

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

年代:1970

数据来源: WILEY

摘要:

AbstractSamples of oriented DNA prepared by wet spinning have been found to be very useful for physicochemical and biochemical studies with various techniques. The results obtained yield information on such fundamental properties of DNA as its hydration, electrical conductivity, and its interaction with irradiation and mutagenic and carcinogenic substances. Against this background a detailed description is given of the wet, spinning apparatus and of the techniques developed to produce bigger samples from spun films of oriented DNA. Photographic illustrations are used to give a clear picture of the various details. Extensions of the wet spinning method are discussed.

ISSN:0006-3592    

DOI:10.1002/bit.260120109

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

年代:1970

数据来源: WILEY

摘要:

AbstractThe processing of fermentor‐grown, edible yeast involves the removal of water. This can be accomplished through concentration followed by drum or spray drying. This study presents the essential physical properties of yeast solutions necessary for calculation of production economics. In addition, our initial studies of vacuum concentration show that some of the cell leakage necessary for good drying characteristics occurs. The residence time during concentration is also sufficient, to yield 1‐2 log cycles of kill which are mandatory since the final product, should contain no viable ce

ISSN:0006-3592    

DOI:10.1002/bit.260120110

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

年代:1970

数据来源: WILEY

摘要:

AbstractOne important economical method for producing singlecell protein is to spray dry the cultured cells. This study presents some preliminary data on the effects of spray drying on cell viability. Under conditions similar to those for the production of spray‐dried milk, 4–5 log cycles destruction occurred. The results indicate that, the activation energy for thermal destruction of yeast was reduced from the normal heat treatment value of 84 kcal/°K mole to about 38 kcal/°K

ISSN:0006-3592    

DOI:10.1002/bit.260120111

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

年代:1970

数据来源: WILEY