摘要:

AbstractA cellulose‐binding endoglucanase (endoglucanase A) ofCellulomonassp. ATCC 21399 was purified to immunological homogeneity by affinity chromatography ob H3PO4‐swollen cellulose. This method of purification turned out to be an easy and very gentle method for obtaining a high yield of cellulose‐binding endoglucanase. The purified enzyme was immunologically homogeneous but appeared heterogeneous when analyzed by denaturing polyacrylamide gel electrophoresis. In addition to the cellulose‐binding of endoglucanase A, the enzyme also had a strong affinity for Concanavaline A, indicating that the enzyme was glycosylated. Purified endoglucanase A showed an endo mode of action on carboxymethylcellulose. The enzyme could hydrolyze microcrystalline cellulose when acting alone, and the enzyme had a high specific activity on H3PO4‐swollen

ISSN:0006-3592    

DOI:10.1002/bit.260290702

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

年代:1987

数据来源: WILEY

摘要:

AbstractThe concepts of feed pretreatment, phase separation, and whole‐cell immobilization technology have been incorporated in this investigation for the development of rational and cost‐effective two‐ and three‐stage methane recovery systems from water hyacinth (WH)Analyses of laboratory data reveal that a three‐stage system could be designed with an alkali pretreatment stage [3.6% Na2CO3+ 2.5% Ca(OH)2W/W, 24 h HRT] followed by an open acid reactor (2.1 days HRT) and closed immobilized methane reactor (12 h HRT), providing steady‐state COD conversion of 62–65%, TVA conversion of 91–95%, and gas productivity of 4.08–5.36 L/L reactor volume/day with 82% methane. A gas yield of 50 L/kg WH/day (dry wt basis) at 35–37°C is possible with this system. Insulation bricks, with particle size distribution of 500–3000 μm, were used as support material in the reactors at organic loading rate of 20 kg COD/m3day. The reactors matured in 15–18 weeksSubstantial reduction in retention time for the conversion of volatile acids in immobilized methane reactors prompted further research on the combined immobilized reactor to make possible an additional reduction in the cost of a WH‐based biogas system. Evaluation of laboratory data reveals that a two‐stage system could be designed with an open alkali pretreatment stage and a combined immobilized reactor (12 h HRT), providing steady‐state COD conversion of 53% and gas productivity of 3.1 L/L reactor volume/day with 86% methane. A gas yield of 44 L/kg WH/day (dry wt basis) at 35–37°C could be obtained from this system. Insulation bricks, with 500–1000 μm particle size distribution, was used as support material at an organic loading rate of 15 kg COD/m3day. Notwithstanding the fact that the technology in this study has been developed with water hyacinth as substrate, the implicit principles could be ex

ISSN:0006-3592    

DOI:10.1002/bit.260290703

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

年代:1987

数据来源: WILEY

摘要:

AbstractAcinetobacterhas been found to be the major species responsible for mediating biological phosphate removal. The growth kinetics and phosphate uptake were investigated for an isolatedAcinetobacterstrain growing in a defined medium. The phosphate uptake is dependent on growth rate, temperature, and pH. Polyphosphate granules occurred in a balanced growth stage. The maximum phosphorus content in cells was 4.8% at the dilution rate of 12 day−1. The specific phosphate uptake rate was found to be a quadratic polynomial function of the dilution rate. Increased calcium (up to 36 mg/L) and magnesium (up to 15 mg/L), and the addition of yeast extract (100 mg/L), primary effluent (20%), and fluoride (10 mg/L) did not affect phosphate uptake. Anaerobic conditioning (N2stripping), low pH (CO2stripping), and addition of sodium acetate under anaerobic conditions failed to stimulate immediate phosphate release. Nevertheless, After 21–24 h, the phosphate release was ca. 3, 5, and 15 mg P/g cell, respectively, for N2purging, the addition of acetate, and CO2purging. For two‐stage completely stirred reactor operation, there was negligible phosphate overplus at the second reactor when phosphate was added, when the first reactor was subjected to phosphate limitation. When both phosphate and carbon limited the growth in the first reactor, there was slight phosphate accumulation under endogenous respiration conditions in the second re

ISSN:0006-3592    

DOI:10.1002/bit.260290704

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

年代:1987

数据来源: WILEY

摘要:

AbstractBlue–green algae,Spirulina platensis, is cultivated under photoautotrophic growth conditions designed to have nearly uniform growth rate throughout the fermentor by illumination both sides of a rectangular vessel. The results show that growth rate and bioenergetic yield are a function of light intensity. Several kinetic models are considered to express the relationship between growth rate and light intensit

ISSN:0006-3592    

DOI:10.1002/bit.260290705

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

年代:1987

数据来源: WILEY

摘要:

AbstractDuring the fermentor feeding phase in constant fed‐batch ethanol fermentation of molasses, the ethanol production rates are constant and are correlated to the sugar feeding rates by a Monod‐like equation. The parameters of this Monod‐like correlation depend on the sugars concentration of the feeding mash. A model is proposed to explain the constancy of the ethanol production rate experimentally observed. From the Monod‐like correlation it is possible to evaluate the maximum value of the mash feeding rate to be used in order to have a completely fermented medium just at the end of the feedin

ISSN:0006-3592    

DOI:10.1002/bit.260290706

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

年代:1987

数据来源: WILEY

摘要:

AbstractA respiratory‐deficient, mutant ofKluyveromyces fragiliswas isolated using a ethidium bromide mutagenesis. It was characterized by a loss of cytochromesa+a3 and by an improvement of its inulinase activity. Under anaerobic conditions this mutant was always better than the wild strain for ethanol production especially from Jerusalem artichoke extracts containing large amounts of high polyfructosans ("early" extracts

ISSN:0006-3592    

DOI:10.1002/bit.260290707

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

年代:1987

数据来源: WILEY

摘要:

AbstractContinuous culture was employed to study plasmid instability in an amylase‐producingBacillus subtilis1A289 that was genetically manipulated. No true steady state could be obtained with 1A289(pEAA)‐strain (plasmid)‐due to its structural instability, which occurred both with glucose and Maltrin‐100 as limiting carbon sources. The plasmid, pEAA (CmR, amy+, i.e., chloramphenicol resistant, amylase positive) degenerated into a smaller plasmid, pEAA1 (CMR, amy−) that was stable. There was a direct correlation between amylase‐producing ability and this structural instability sincefamy(fraction of cells with amylase‐producing ability) reached zero at the same time thatf(fraction of cells that are resistant to chloramphenicol) reached its maximum level. Since the deletion in pEAA was larger than the original amylase‐gene insert, either all of part of the insert is absent from pEAA1. Though on discernible change in 1A289(pHV33), where pHV33 is the vector plasmid, was observed during continuous cultivation, its behavior was different from that of the stab

ISSN:0006-3592    

DOI:10.1002/bit.260290708

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

年代:1987

数据来源: WILEY

摘要:

AbstractToluene was oxidized by a mutant strain ofPseudomonas putida(strain NG1) to tolueneCis‐Glycol (TCG). Product was accumulated in fed‐batch cultures to concentrations (18–24 g/L) higher than hitherto achieved.In vitroactivities of toluene dioxygenase fromP. PutidaNG1 were fivefold lower than that from the toluene‐grown wild‐type organism, whereas comparable activities of both catechol 2,3‐ and catechol 1,2‐oxygenase were obtained; irreversible inhibition of toluene dioxygenase activity by TCG was shownin vitro.Ammonia deprivation during the production phase limited the growth of revertant organisms but had little effect on either the duration (25h) of the process or the final concentration of TCG achieved. The rate of glucose utilization decreased throughout the biotransformation and cell death accompanied the cessation of TCG accumulation in cultures. These changes were a consequence of TCG formation and a cooperative toxic effect was demonstrated for toluene and TCG. Adenylate energy charge values decreased from ca. 0.8 to 0.2 over the course of the biotransformation but were maintained above 0.5 in the absence of TCG. Similarly, cellular AMP levels increased dramatically during biotransformation, presumably as a consequence of RNA degradation, but were maintained at low levels in the absence of TCG. The results suggest that TCG is the mediate of a gradual deterioration in the state of the culture which leads to a loss of bothin vivoandin vitrotoluence dioxygenase activity and a marked decrease in cult

ISSN:0006-3592    

DOI:10.1002/bit.260290709

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

年代:1987

数据来源: WILEY

摘要:

AbstractImmobilization ofMycobacteriumPY1 andXanthobacterPY2 in alginate and in or on hydroculture has a minor influence on the maximum rate of oxidation of propene and ethane. The apparentKmvalues of the immobilized cells are slightly higher than those of the free cells, indicating the presence of diffusion limitation in the immobilized systems. Both bacterial strains rapidly lose their alkene‐oxidizing activity when the water activity is decreased. This decrease in activity is so rapid that most of the activity is lost already when the pores of the pertinent supports are still filled with water. Therefore, it is not possible with this system to study the transition of mass transfer of substrates entirely in the water phase to mass transfer to substrates entirely through the gas phas

ISSN:0006-3592    

DOI:10.1002/bit.260290710

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.260290711

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

年代:1987

数据来源: WILEY