摘要:

AbstractThe great disarray in the measurements of the maximum efficiency of conservation of light energy in photosynthesis is an outstanding problem in the development of photosynthetic biotechnology. The short‐term measurements of the efficiency based on O2release by suspensions of cells or chloroplasts have given minimum quantum demands between 4 and 12hv/O2. The defect of the short term measurements is that the effects of growth conditions, which can alter the efficiency by a factor of 2, have been generally ignored. In contrast, the steady‐state growth method, which depends on measurement of the maximum growth yield in photosynthesis, ensures that growth and photosynthesis are normally coupled. This growth method indicates that the minimum quantum demand lies in the relatively narrow range of 5.3 to 8.6hv/O2. The question of whether the minimum quantum demand is less or greater than 8hv/O2is a crucial test for present theoretical concepts of the conversion of radiant energy to chemical energy in photosynthesis. To obtain the definitive maximum value more rigorously controlled measurements of photosynthetic efficiency in growing organisms are essent

ISSN:0006-3592    

DOI:10.1002/bit.260250802

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

年代:1983

数据来源: WILEY

摘要:

AbstractGlucoamylase and glucose oxidase have been immobilized on carbodiimide‐treated activated carbon particles of various sizes. Loading data indicate nonuniform distribution of immobilized enzyme within the porous support particles. Catalysts with different enzyme loading and overall activities have been prepared by varying enzyme concentration in the immobilizing solution. Analysis of these results by a new method based entirely upon experimentally observable catalyst properties indicates that intrinsic catalytic activity is reduced by immobilization of both enzymes. Immobilized glucoamylase intrinsic activity decreases with increasing enzyme loading, and similar behavior is suggested by immobilized glucose oxidase data analysis. The overall activity data interpretation method should prove useful in other immobilized enzyme characterization research, especially in situations where the intraparticle distribution of immobilized enzyme is nonuniform and unknow

ISSN:0006-3592    

DOI:10.1002/bit.260250803

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe copolymerization method of immobilization was used to obtain preparations of enzymes covalently incorporated in polyacrylamide gel. They possess properties making them suitable for practical use. First, the preparations are hundreds of times more stable againstirreversiblethermoinactivation than native enzymes. Second, on immobilization, thereversibleconformational changes which also lower enzyme activity at elevated temperatures are completely suppressed. As a result, the temperatures of maximum activity for trypsin and α‐chymotrypsin covalently entrapped in polyacrylamide gel are 75 and 70°C, respectively—25 and 30°C higher than the corresponding values for the native enzymes. Therefore, the copolymerized enzyme preparations have a high operational stability at elevated temper

ISSN:0006-3592    

DOI:10.1002/bit.260250804

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

年代:1983

数据来源: WILEY

摘要:

AbstractA methodology has been developed for the quantitative assessments of the individual effects of precipitation and chelation of metal ions in an anaerobic digester.

ISSN:0006-3592    

DOI:10.1002/bit.260250805

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe relative importance of the individual effects of precipitation and chelation of metal ions in anaerobic digestion is assessed. Experimentally determined soluble metal ion levels are compared with predicted levels obtained by using a previously described methodology.1It is found that soluble metal complexes may increase the level of soluble metals in the presence of CO 32−and S2−by a factor of up to 104. The formation of a soluble complex may increase or decrease the availability of the metal ion in question for microbial uptake. Two case studies are presented, one using a defined medium and one a complex medium. It is possible, in the case of the defined medium, to accurately predict the free metal ion concentration using the methodology previously developed.1While the identification of the presence of natural chelating compounds in a complex medium is not routinely possible, the significant discrepancy between the measured level of the soluble metal ion Fe2+and the calculated level in the case studies presented indicates that natural chelating compounds may play a vital role in providing available metal ions to the microorganisms of an anaerobic dig

ISSN:0006-3592    

DOI:10.1002/bit.260250806

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

年代:1983

数据来源: WILEY

摘要:

AbstractA simple method of preparing a chitin‐immobilized α‐amylase and glucoamylase from the protease‐ and glycosidase‐less Mutant HF‐15 ofAspergillus awamori var. kawachiwas developed and used for the production of high‐glucose syrup. The glucoamylase was tightly bound onto chitin without the aid of a crosslinking agent because the enzyme contained a specific binding site for chitin. Continuous production of high glucose concentrate from a highly concentrated α‐amylasetreated gelatinized starch substrate (about 45% total solids) was undertaken successfully with the use of a column‐packed chitin‐immobilized amylase. The activity of the column was stable for more than 20 days of continuous operation and the product was found to be only glucose with an average dextrose equivalent value of more than 97%. The final product showed no isomaltose or panose contamination, indicating that the immobilized amylase had no transglucosidation activity. The immobilized amylase was most active in the conversion of gelatinized starch to glucose at 55°C and pH 2.5 to 5.0. Drying the chitin‐immobilized amylase resulted in the decrease of activity and shortening of storage life, whereas a storage life of up to 80 days was attained without affecting its original activity when kept under

ISSN:0006-3592    

DOI:10.1002/bit.260250807

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe filtration characteristics of the penicillin broth can be monitored semicontinuously using an automatic filtration probe. This probe operates aseptically and the broth samples (filtrate and filter cake) are recycled to the fermentor after each filtration. The collected data—filtrate volume and filter cake volume versus filtration time—can be related to the total biomass concentration in the fermen

ISSN:0006-3592    

DOI:10.1002/bit.260250808

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe fission yeastSchizosaccharomyces pombewas cultivated in a chemostat at dilution rates ofD= 0.03, 0.05, 0.10, and 0.20 h−1. After steady state had been reached, the amount of dry matter, number of cells, concentration of residual sugar, yield coefficient (Y), and some morphological properties of the cells were estimated. Curves reflecting the dry mass, number of cells, and cell mean volume show a changing coordination between the growth rate and the rate of cell division, with respect toD. In addition, it could be concluded that in dividing cells the cell septum is localized asymmetrically; Two nonidentical cells differing both in length and volume result. The degree of asymmetry is a function of the dilution rat

ISSN:0006-3592    

DOI:10.1002/bit.260250809

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

年代:1983

数据来源: WILEY

摘要:

AbstractA new method is presented for the treatment of gel‐type supports, used for immobilizing microbial cells and enzymes, to obtain high mechanical strength. It is particularly useful for ethanol fermentation over gel beads containing immobilized viable cells, where the beads can be ruptured by gas production and the growth of cells within the gels. This method consists of treating agar or carrageenan gel with polyacrylamide to form a rigid support which retains the high catalytic activity characteristic of the untreated biocatalysts. The size and shape of the biocatalyst is unaffected by this treatment. The method involves the diffusion of acrylamide,N,N′‐methylenebisacrylamide and β‐dimethylaminopropionitrile (orN,N,N′,N′‐tetramethyl‐ethylenediamine) into the performed biocatalyst beads followed by the addition of an initiator to cause polymerization within the beads. Treated gels have been used for the continuous fermentation of glucose to ethanol in a packed column for over two months. During this operation, the gel beads maintained their rigidity, and the maximum productivity was as high as 50 g h−1L−1gel. There was no appreciable de

ISSN:0006-3592    

DOI:10.1002/bit.260250810

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

年代:1983

数据来源: WILEY

摘要:

AbstractAlcohol fermentation was studied with an emphasis on the separation of cell growth and alcohol production stages. Experiments were conducted to establish the optimal conditions for alcohol production in batch fermentations and to simulate continuous fermentations with cell feeding at various stages. It was found that the glucose concentration should be kept under 10% (w/v), and the temperature should be between 40 and 42.5°C for maximum specific alcohol productivity. If the cell concentration is increased, a decrease in specific alcohol productivity is observed. Higher cell concentrations are needed for higher final alcohol concentrations. Among the cell feeding procedures into alcohol production stages, a cocurrent design was found to be better than recycle and countercurrent designs

ISSN:0006-3592    

DOI:10.1002/bit.260250811

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

年代:1983

数据来源: WILEY