摘要:

AbstractInvertase and α‐galactosidase have been immobilized in hollow fiber cartridges with no detectable enzyme leakage and used for the hydrolysis of sucrose and raffinose, respectively. For both hollow fiber immobilizes enzymes nearly complete substrate conversion is possible. Enzyme stabilities in polysulfone hollow fibers which have been preconditioned with bovine albumin approach the stabilities of the free enzym

ISSN:0006-3592    

DOI:10.1002/bit.260190102

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

年代:1977

数据来源: WILEY

摘要:

AbstractIn hydrocarbon fermentation, the efficiency of hydrocarbon uptake by cells ins one of the keys to the economical production of single‐cell protein. This work is concerned with characterization of cultures with two liquid phases for understanding the hydrocarbon uptake process by cells. Batch cultivation ofCandida lipolyticawas carried out in shaking flasks and in a tower fermentor with motionless mixers. Micorscopic observation and cell and hydrocarbon concentration distribution in batch cultivation showed that some cells are attached to the large oil drops ad others are free from them. Interfacial tension between oil and water and Sauter mean drop size decreased as cultivation proceeded. On the basis of the experimental results, the process of hydrocarbon uptake by cells is discusse

ISSN:0006-3592    

DOI:10.1002/bit.260190103

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

年代:1977

数据来源: WILEY

摘要:

AbstractIn 18 batch‐fermentation experiments, baker's yeast was grown in an enriched mineral medium, containing 10% by weight glucose, at various pH and temperature levels. The pH and temperature are just two representative engineering variables which and be easily varied at negligible cost. The commercial yeast inoculum, .20% by weight or about .16% viable cells, was selected to represent industrial (nonsterile) conditions. FreeL‐lysine, ethanol, and cell growth were followed in time for each batch run held at a fixed pH and temperature. The maximum free lysine level reached at either 10½ or 24 hr occurred at a pH of 5 and 32°C. At 24 hr, the peak free lysine level, 120 mg/liter, is three times as great as the uncontrolled pH counterpart. In terms of totalL‐lysine, (free plus protein‐bound) the peak represents a 25% improvement over the uncontrolled case, based on an average 3.5% lysine level per cell weight. The greatest measured cell level, .9% by weight in the fermentation broth, or a 5½‐fold increase over the inoculum, was reached during the 36°C and pH 3 run, while the largest measured ethanol value (3%, or 30% conversion by weight from glucose) was achieved during the 28°C and pH 6 experiment. The optimal lysine run produced, however, no less than 15% of the maximum cell and 30% of the maximum

ISSN:0006-3592    

DOI:10.1002/bit.260190104

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe reliability of the process of Ramanathan and Gaudy (Biotechnol Bioeng.,13, 125 (1971)) for the completely mixed activated‐sludge process holding the recycle cell concentration,XR, as a system constant with respect to step changes in hydraulic retention time was investigated. The experiments were run at initial dilution rates of ⅛, ⅙, ¼, and ½ hr−1treating a soft drink bottling wastewater. The influent substrate concentration was maintained at 1000 mg/liter chemical oxygen demand and the hydraulic recycle ratio at 0.3. The recycle sludge concentration was maintained at about 7000 mg/liter.It was found that the system could accommodate hydraulic shock loads up to 200% positive changes and down to 50%negative changes without disruption of the effluent quality. Shorter retention time of the range studied, from 2 to 8 hr, has the advantage of shorter response time with respect to the response of the concentration of biological solids in th

ISSN:0006-3592    

DOI:10.1002/bit.260190105

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

年代:1977

数据来源: WILEY

摘要:

AbstractDespite the importance of biomass as a parameter in fermentation processes, there are no commercially available sensors suitable for its measurement. An indirect approach for the assessment of biomass concentration can be based on material balances and on the direct monitoring of fermentation parameters for which there are established sensors (e.g., gaseous oxygen and carbon dioxide). As a consequence, this method requires no assumption of cellular yield coefficients or rate constants. This approach is also readily adaptable to general use since it requires only some knowledge of the compositions of the substrate, cells, and noncellular products.

ISSN:0006-3592    

DOI:10.1002/bit.260190106

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe economics of yeast production depend heavily upon the cellular yield coefficient on the carbon source and the volumetric productivity of the process. The application of an on‐line computer to maximize these two terms during the fermentation requires a continuous method of measuring cell density and growth rate. U fortunately, a direct sensor for biomass concentration suitable for use in industrial fermentations is not available. Material balancing, with the aid of on‐line computer monitoring, offers an indirect method of measurement. Laboratory results from baker's yeast production in a 14‐liter fermentor (with a PDP‐11/10 computer for on‐line analyses) show this indirect measurement technique to be a viable alternative. From the oxygen uptake and carbon dioxide production data, gas flow rate, and ammonia addition rate, the cell density during the fermentation has been estimated and found to compare well with actual fermenta

ISSN:0006-3592    

DOI:10.1002/bit.260190107

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

年代:1977

数据来源: WILEY

摘要:

AbstractSucciylated cyclodextrin glycosyltransferase (EC.3.2.1.19) of an alkalophilicBacillussp. was adsorbed on a vinylpyridine copolymer. The enzyme had about 25% of the activity of soluble enzyme added. No increase of pH or thermal stability of the enzyme was observed by the adsorption, whereas optimum temperature for the enzyme action was shifted from 50 to 55°C. The enzyme converted starch to cyclodextrins without significant loss of activity under the conditions of 4 times reusing of 6 hr conversion by the batch system or 2 weeks continuous reaction by the column system at 55°C and pH 8.0. About 46% of the potato starch solution [15% (w/v)] was converted to cyclodextrins by the enzyme, and 52% was converted by the simultaneous action of the enzyme and alkaline pullulanase of alkalophilicBacullussp.(No.202‐1). These values were almost the same as those obtained by the soluble enzyme or enzyme sys

ISSN:0006-3592    

DOI:10.1002/bit.260190108

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

年代:1977

数据来源: WILEY

摘要:

AbstractChymotrypsin has been immobilized to several nonporous magnetic materials. Nickel particles were considered to be most suitable as immobilized enzyme supports. Chymotrypsin immobilized to nonporous magnetic supports was not fouled significantly by6 either whole milk or clarified yeast homogenate. AE‐cellulose‐chymotrypsin was rapidly fouled by both these materials and chymotrypsin immobilized to acrylic‐based ion exchangers was slowly fouled. Immobilized enzyme activity was found to be inverted proportional to particle diameter for nonporous rock magnetite particles. Immobilization by adsorption and then glutaraldehyde crosslinking was used to produce controlled amounts of chymotrypsin on the particles. Esterolytic activity increased with enzyme loading but caseinolytic activity did not increase. Chymotrypsin is inhibited by metal ions from the magnetic supports. It is partially protected by use of a preliminary protein coating and may be reactivated by incubation with EDTA o

ISSN:0006-3592    

DOI:10.1002/bit.260190109

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

年代:1977

数据来源: WILEY

摘要:

AbstractAmyloglucosidase was covalently bound to collagen sheets by a previously described method. The time of acidic methylation (first step of the collagen activation process) was important to obtain a good enzymatic surfacic activity. Homogeneity of the coupling procedure on the surface of collagen films was shown. Some properties of free enzyme were not affected after grafting: optimum pH and temperature, activation energy, andKmfor maltose. Heat stability of the bound enzyme was slightly better;Kmfor soluble starch increased fivefold. In contrast, the maximal velocity in the presence of soluble starch remained four times that of maltose hydrolysis.Amyloglucosidase collagen membranes were used in a helicoidal reactor to produce glucose from maltose or soluble starch solutions. Tracer studies have shown that the helicoidal reactor behaved as a CSTR. The influence of maltose concentration and flow rate on conversion was studied and confirmed the absence of diffusional limitations for maltose. Recycling of concentrated solutions of maltose and soluble starch indicated strong diffusional restrictions for soluble starch. The catalytic support kept all its activity for 18 days continuous operation at 40°C and 80% after 17 months storage at 4°

ISSN:0006-3592    

DOI:10.1002/bit.260190110

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

年代:1977

数据来源: WILEY

摘要:

AbstractA rapid chemical procedure based on the solubility of a holocellulose sample in a system of dimethyl sulfoxide with paraformaldehyde has been developed to provide a laboratory method for predicting dry matter digestibility of cellulose containing samples. The amount of dry matter solubilized by the chemical procedure was closely correlated with anaerobic,in vitro, rumen fluid digestion and with digestibility as measured by aerobicCellulomonas, sp. bacteria. The quantity of solvent and dissolving time had little effect on solubility over a wide range. The method is rapid, well suited for various cellulosic materials, and may be carried out with simple equipment and facilities.

ISSN:0006-3592    

DOI:10.1002/bit.260190111

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

年代:1977

数据来源: WILEY