ISSN:0268-2575    

DOI:10.1002/jctb.280560102

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractRenewed world interest in enzyme biotechnological industries now derives from the expectation that many new biocatalysts will be created by genetic engineering associated with protein engineering designer techniques, or by chemical modification of existing enzymes by use of protein tailoring methods. The biocatalysts produced are mainly enzymes, abzymes (catalytic antibodies) and synthesis (synthetic analogues or mimics), and these will be used in industry, synthesis, therapy: and in bioanalysis of components of foodstuffs, and the environment including water, air and soil. The biocatalysts, including whole cells, are firstly incorporated into a particular bioreactor form by use of enzyme engineering techniques such as immobilization, and are then used, as appropriate, to modify their substrates. Improved processing or enhanced products are thereby achieved in the case of manufacturing industry: or monitoring signals are generated, often in the form of a measurable change in current flow, in the case of environmental biosensors. Designer enzymes and cells can be made now for identified applications where the presently available biocatalysts are inadequate, incompatible or uncompetitive.

ISSN:0268-2575    

DOI:10.1002/jctb.280560103

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe fluidised bed cell is an electrolytic reactor which is designed to provide higher ion‐transfer conditions during electrolysis by breaking up the barrier layer at the cathode, thus enabling metals to be removed efficiently from dilute solutions. The effectiveness of the method as a means of removing metals from effluent to meet discharge consent levels is studied for the in‐situ removal of cobalt from dilute solution. The effects of cathode density, pH, reaction time, buffer solution composition, buffer concentration and agitation on the removal of cobalt are reported and expressed in terms of the percentage removal of cobalt (αCo), the efficiency for cobalt deposition (∞Co), and the energy consumption (WCo) for 1 kg of cobalt deposited. The results show that cobalt can, under optimised conditions, be removed from dilute solutions to a residual level of 0

ISSN:0268-2575    

DOI:10.1002/jctb.280560104

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractAlthough stable foams on activated sludge plants have been under discussion for about 25 years, their structure and the reasons for their structure are still unresolved. The paper describes a study, based on cryogenic electron microscopy and rheology, into foam structure. The results have shown that a foam consists of air bubbles held in a dense matrix of filamentous microbes and that the individual bubbles were surrounded by a film which contained cellular material. Rheology measurements showed that foams had an appreciable viscosity which varied with the concentration of solids in the foam. A significant difference occurred between the foam viscosities and those of non‐foaming activated sludge that had been thickened to similar concentrations of solid

ISSN:0268-2575    

DOI:10.1002/jctb.280560105

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractSelective separation of metal ion from a liquid solution with the help of different permeation rate of solutes through liquid membranes was performed. The salts used were ZnCl2, CdCl2, NiCl2. D2EHPA and LIX64N were used as carrier to study the extraction rate of the solutes. The results show that at low pH value of external phase the order of degree of extraction by D2EHPA or LIX64N is Zn>Cd>Ni, while at high pH value with the presence of ammonia in the feed solution the order of degree of extraction is reversed to Ni>Cd>Zn. The results also indicate that when the mixed carrier is used an enhanced effect on the extraction was observed. Synergistic effect was also noted when comparing the cases with mixed carriers to those with pure carriers.

ISSN:0268-2575    

DOI:10.1002/jctb.280560106

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractSix bacterial cultures isolated from soil were capable of growing in the presence of methotrexate (MTX). Two strains, PFR‐1 and 3, developed resistance to 500 μg cm−3MTX in the medium and produced elevated levels of the enzyme dihydrofolate reductase (EC 1.5.1.3): 2580 and 2702 U dm−3compared to the sensitive parent strains (28 and 35 U dm−3). Isolate PFR‐3 showed maximum enzyme production (4950 U dm−3, specific activity 12.56 U mg−1in flasks and 5737 U dm−3, specific activity 14.80 U mg−1in 5‐dm3fermenter) during exponential phase of growth (6 h

ISSN:0268-2575    

DOI:10.1002/jctb.280560107

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe results are reported for an investigation into the fungicidal properties of six triphenyltin(IV) compounds representing metal coordination numbers of four through six. These experiments were conducted against a number of soil and plant pathogenic fungi and compared with the results obtained from triphenyltin chloride. While all the compounds examined proved to be effective fungicides, differences at the concentration levels tested were not sufficiently pronounced to relate the degree of toxicity to the molecular structure.

ISSN:0268-2575    

DOI:10.1002/jctb.280560108

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractFormyl‐ and hydroxymethyl‐ derivatives of [3](1,1′)ferrocenophane were enzymatically resolved with fermenting baker's yeast, immobilized lipase, and pig liver est

ISSN:0268-2575    

DOI:10.1002/jctb.280560109

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe effects of the horizontal connection length (0.1 ±Le± 0.5 m), the cross‐sectional area ratio of downcomer‐to‐riser (0.11 ± Ad/Ar± 0.53), and the superficial gas velocity on gas phase holdups in the riser and downcomer were studied. The circulation liquid velocity, the mixing performance and the volumetric mass transfer coefficient in the external‐loop airlift reactors were also measured. The horizontal connection length andAd/Arwere major parameters which strongly affected the performance of external‐loop airlift reactors. Useful correlations in the external‐loop airlift reactors were obtained for gas holdups, the volumetric mass transfer coefficient, the circulation liquid velocity, and

ISSN:0268-2575    

DOI:10.1002/jctb.280560110

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe effect of temperature studies on polyphenol oxidase immobilized on glass beads were carried out in organic solvents. The optimum temperature for catalysis depended on the solvent and varied in a range from 26°C for dichloromethane to 50°C for toluene, benzene and 1,1,1‐trichloroethane. Optimum temperature and activation energy were independent of the water content of the system whereas the inactivation energies decreased as the water content of the system was decreased. The enzyme was stable in toluene up to 50°C although residual activity depended on the water content of the system. Thermoinactivation of polyphenol oxidase in toluene gave an activation energy for enzyme decay of 111.5 kcal mol−1which is consistent with a conformational process. Among the agents employed to protect the enzyme against thermal denaturation 1 % (w/v) short‐chain polyols added to the buffer and 0.5 mmol dm−3p‐nitrophenol added to toluene more than doubled the half‐life

ISSN:0268-2575    

DOI:10.1002/jctb.280560111

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY