摘要:

AbstractHigh activity alkaline protease was obtained when the enzyme was immobilized on Dowex MWA‐1 (mesh 20–50) with 10% glutaraldehyde in chilled phosphate buffer (M/15, pH 6.5). Activity yields of the protease and rennet were 27 and 29, respectively. The highest activities appeared at 60°C, pH 10 for alkaline protease and 50°C, pH 4.0 for rennet. The properties of both proteases were not essentially changed by the immobilization except that theKmvalues of both enzymes were increased about tenfold as a result of immobilization. Both proteases in the immobilized state were more stable than those in the free state at 60°C. Other peptide hydrolases, β‐galactosidase, invertase, and glucoamylase, were successfully immobilized with high activities, but lipase, hexokinase, glucose‐6‐phosphate dehydrogenase, and xanthine oxidase be

ISSN:0006-3592    

DOI:10.1002/bit.260200102

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

年代:1978

数据来源: WILEY

摘要:

AbstractWhole cells ofPseudomonas testosteroni, induced to synthesize steroid‐transforming enzymes beforehand, have been immobilized by entrapment in polyacrylamide gel. The immobilized cells have then been used to catalyze the continuous Δ1‐dehydrogenation of Reichstein's substance S under various conditions in the presence of phenazine methosulfate (PMS), an electron acceptor for the cell‐free Δ1‐dehydrogenase. The presence of PMS substantially increases the rate of reaction when fed with the steroid substrate to a continuous stirred tank reactor containing the immobilized cells. The operational half‐life of the Δ1‐dehydrogenase activity of the cells, about 103 hr under the best operating conditions, is essentially unaffected by the presence of PMS. Though the acceleration of the reaction may be due to PMS‐mediated passage of electrons from some component in the electron transport chain to molecular oxygen, the lack of a similar effect with methylene blue is consistent with the conclusion that PMS functions directly as the electron acceptor for the

ISSN:0006-3592    

DOI:10.1002/bit.260200103

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe effect of oxygen supply onL‐leucine fermentation was investigated employing a leucine‐producing mutant ofBrevibacterium lactofermentum. Since it was not possible to measure oxygen tension below 0.01 atm by a Teflon‐coated oxygen electrode, the degree of satisfaction of the cells' oxygen demand (cells' respiration rate/maximum oxygen demand of cells,rab/KrM) and the redox potential of the culture medium (E.mV) were used as indices to oxygen supply in cultures under low oxygen tension. When the oxygen demand of the cells was satisfied (rab/KrM= 1.0) and theEvalue was between −90 and −110 mV,L‐leucine formation was 26.5 mg‐ml. When the oxygen demand of the cells was not satisfied (rab/KrM= 0.85) and theEvalue was between −200 and −220mV,L‐leucine accumulation was 29.7 mg/ml. When the oxygen supply was extremely limited (rab/KrM= 0.27) and theEvalue was −280 mV.L‐leucine formation was 12.9 mg/ml. A new method which simultaneously measures the redox potential and dissolved oxygen was applied to the determination of the critical dissolved oxygen level for cell respiration (PLcrit), which was too small to be detected by conventional oxygen electrodes. The value ofPLcritof the leucine producer was

ISSN:0006-3592    

DOI:10.1002/bit.260200104

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

年代:1978

数据来源: WILEY

摘要:

AbstractNitrification and denitrification are important microbiological reactions of nitrogen. In this work, the kinetics of these reactions have been investigated based on a Monod‐type expression involving two growth limiting substrates: ammonium nitrogen and dissolved oxygen for nitrification and nitrate nitrogen and dissolved organic carbon for denitrification. The kinetic constants and yield coefficients were evaluated for both these reactions. Past experimental work was used to determine the constants for the nitrification reaction. For the denitrification reaction, experiments were performed in a stirred tank reactor under conditions such that only one substrate was growth limiting. Steady‐state values of the substrate concentrations in the reactor were determined at various dilution rates. These data were analyzed to obtain the kinetic and stoichiometric constants. From these constants it was concluded that in the range of nitrate nitrogen concentrations encountered in waste water, the denitrification reaction can be considered a first‐order reaction. It was also found that three times as much organic carbon is required as nitrate nitrogen for complete nitrogen re

ISSN:0006-3592    

DOI:10.1002/bit.260200105

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

年代:1978

数据来源: WILEY

摘要:

AbstractVarious aspects of process water recycle in a continuous flow fermentation process are analyzed. Simple mass balance equations in terms of product and feed components for a single‐stage reactor producing biomass are developed. Constraints on the recycle ratio, imposed by the efficiency of the dewatering stage, are examined. The recycle analysis is extended using a kinetic growth model incorporating water soluble product formation and growth inhibition. The potential effect of recycle on substrate conversion and product accumulation is also examined and the concept of a critical recycle ratio in fermentation processes is develope

ISSN:0006-3592    

DOI:10.1002/bit.260200106

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

年代:1978

数据来源: WILEY

摘要:

AbstractLysozyme has been immobilized on chitosan, a polyaminosaccharide, without using any intermediate reagent. The best pH conditions for operating the chitosan columns have been determined and the best eluting agent was found to be a 2% solution of propylamine. The lysozyme activity was determined after reacting lysozyme with the product of glycolchitin and Remazol Brilliant Blue R. The recovery of lysozyme from chicken egg white yields lysozyme with 55% activity.

ISSN:0006-3592    

DOI:10.1002/bit.260200107

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

年代:1978

数据来源: WILEY

摘要:

AbstractPoly(methoxygalacturonide) lyase (PMGL) (E.C. 4.2.2.10) was purified from a commercial preparation and immobilized by the metal link method. The properties of DEAE‐cellulose‐Ti‐PMGL and of porous glass‐Ti‐PMGL were compared with those of the native enzyme; despite the presence of the metal and the heterogeneity of the substrate, pectin, typical substrate–enzyme‐support interactions were demonstrated by shifts in pH optima andKMvalues. The possible industrial application of DEAE‐cellulose‐Ti

ISSN:0006-3592    

DOI:10.1002/bit.260200108

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe growth behavior ofChaetomium cellulolyticum, a new cellulolytic fungus, has been examined in slurry fermentation systems using various chemically pretreated sawdusts from hardwoods as substrates. Both acid‐ and alkali‐pretreatment methods were used and the fermentation media included the spent pretreatment liquor in an attempt to concurrently maximize substrate utilization and minimize the biological oxygen demand (BOD) level in the process effluent. Diauxic growth patterns were found in the three cases studied, suggesting an initial utilization of soluble hemicellulose sugars followed by utilization of the insoluble cellulose. This behavior patterns was supported by separate growth experiments using the major sugars of hemicellulose as carbon sources. The organism was found to be a good convertor of both cellulose and hemicelluloses into single cell protein (SCP). In terms of rate and extent of protein production in the insoluble biomass product, acid pretreatment appears to be better than alkali pretreatment if the product is intended as ruminant f

ISSN:0006-3592    

DOI:10.1002/bit.260200109

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

年代:1978

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260200110

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

年代:1978

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260200111

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

年代:1978

数据来源: WILEY