摘要:

AbstractA Comprehensive review of the tractic and strategies that are available to the drug discovery process using combinatorial techniques.

ISSN:0268-2575    

DOI:10.1002/jctb.280640402

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe reactions of phenol with dichloromethane using quaternary ammonium salts as a liquid–liquid phase‐transfer catalyst in an organic solvent/alkaline solution were investigated. The technique of phase‐transfer catalysis had a dramatic accelerating effect on the reaction and increased the yield of diphenoxymethane by more than 95%. The effects of catalysts, temperature, and basic concentration on reaction rate were studied in order to find the optimum operating conditions for this reaction. Experimental results indicated that a potassium hydroxide was preferred over sodium hydroxide in order to enhance the reactivity of the reaction. The reaction rate constant and the distribution coefficient of the intermediate product were obtained. During the reaction, the concentration of the intermediate product was also measured in order to study its behavior in the liquid–liquid

ISSN:0268-2575    

DOI:10.1002/jctb.280640403

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe enzyme salicylate hydroxylase was produced fromPseudomonas putidaUUC‐1 in an 80 dm316 h batch fermentation process yielding, ∼ 9 K units per 60 dm3. This enzyme preparation has been studied for its application in the construction of biosensor systems, e.g. carbon past electrodes, screen‐printed carbon electrodes, and disposable carbon enzyme electrodes, which will be used for the rapid estimation of salicylate in blood sample. The linear range of the disposable carbon enzyme electrode in response to salicylate was achieved to 1·8 mmo

ISSN:0268-2575    

DOI:10.1002/jctb.280640404

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThis paper studies the feasibility of photocatalytic degradation of organophosphorus pesticides using thin films of TiO2. The results show that 0·65 × 10−4mol dn−3of dichlorvos, monocrotophos, phorate, parathion can be completely photocatalytically degraded into PO 43−within a short time under illumination with a medium pressure mercury lamp of 375 W. The effect of parameters such as he amount of TiO2attached, initial concentration of organphosphorus pesticides, initial pH, amount of air flow, concentrations of H2O2and Fe3+on the photocatalytic degradation are studied. The possible mechanisms of photocatalytic degradation are discussed. It is our assumption that the degradation reactions occur on the surface of TiO2via primary produced oxidizing species such as the OH radical and O 22−, after 80 h illumination, there is no significant loss of the photocatalytic act

ISSN:0268-2575    

DOI:10.1002/jctb.280640405

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractA biphasic organic/aqueous membrane bioreactor, which combined chemical reaction with continuous extraction of production in the aqueous phase, was investigated. Lipase fromCandida Cylindraceawas used as catalyst with the hydrolysis of triglycerides, to fatty acids and glycerol, as a model‐system for studying the optimal operating conditions. Asymmetric capillary membranes, made of polyamide, were used as support for the enzyme, which was immobilized into the sponge layer of the membrane by cross‐flow filtration. The catalytic behavior of lipase, both immobilized in a hydrophilic membrane and free in solution, was compared. The effect of pH, temperature and substrate concentration on reactor performance were studied. The catalytic stability of the immobilized enzyme was improved compared with the enzyme in solution. The immobilized lapse showed no deactivating in an operating period of 16 days whereas lipase in solution gave an 80% decrease in specific activity after 2 days of continuous operation. The specific activity of immobilized lipase was significantly influenced by the amount of enzyme loaded into the membranes. The optimal range of immobilized protein was between 2 and 12 mg cm−3. The positive results obtained with the model‐system were also confirmed using the biphasic organic/aqueous membrane bioreactor in a potential practical application, namely the conversion and separation of one enantiomer from an organic racemic mixture of a

ISSN:0268-2575    

DOI:10.1002/jctb.280640406

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractIn the present study the stabilization with glutaraldehyde of permeabilized, non‐viableKluvernomyces lactiscells with β‐galactosidas (β‐D‐galactosidase galactohydrolase, EC 3.21.23) activity has been investigated. The influence of various factors in relation to the glutaradehyde treatment, such as reaction time, temperature and glutaraldehyde and cell concentration, has been considered. The cell biocatalysts showed a good storage and operational stability. The kinetic properties of the biocatalyst in concentration with lactose hydrolysis were found to be comparable to the cell‐

ISSN:0268-2575    

DOI:10.1002/jctb.280640407

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractA laboratory‐scale anaerobic down‐flow fixed‐bed reactor, operating at 35°C, was used to treat abattoir wastewater at input soluble chemical oxygen demand (COD) levels ranging from 4·7 to 28·7 g sm−3and volumetric organic loading rates ranging from 2·5 to 25 g COD dm−3day−1. Start up of the reactor was achieved within 35 days using a regime that include stepped increases in input COD and methanol substitution. The effects of the organic volumetric loading rates on soluble (COD) (SCOD) removal were studied at four feed SCOD concentrations between 4·7 and 28‐7 g dm−3. An exponential dependency of the organic volumetric loading rate with the SCOD removal was observed in the range of loading studied, with variation between 1 and 12 g COD sm−3day−1Further increases of the organic loading rates has smaller effects on SCOD removal. A pseudo first‐order kinetic model was used to obtain the gross removal coefficients, the values of which were virtually independent of the feed COD concentration at 6·9 to 7·3 g COD dm−3day−1. The methane yield coefficient decreased slightly from 0·34 to 0·31 dm3g−1COD when the feed SCOD concentration w

ISSN:0268-2575    

DOI:10.1002/jctb.280640408

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe performance of an upflow packed‐bed biofilm reactor (UPBR) was analysed under multi‐substrate limitation by considering simultaneous carbon oxidation and nitrification reactions. Numerical solutions of the proposed model defining the system were obtained for a wide range of operating conditions of illustrate individual substrate limitation behavior. For an inlet concentrating of 75 mg dm−3of NH4‐N and 25 mg dm−3of methanol., the organic substrate was consumed rapidly near the inlet of the reactor while most of the NH 4+‐N was converted in the central region. The concentration profiles within the biofilm indicated that oxygen was limiting near the inlet of the reactor while organic substrate was laminating at the middle of the reactor. Both NH 4+‐N and methanol became limiting near the reactor exit. Detailed analyses were carried out for a wide range NH 4+‐N concentration and for a given concentration of methanol which showed that oxygen could also become limiting even at the

ISSN:0268-2575    

DOI:10.1002/jctb.280640409

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractLignocaine (Lg) selective PVC membrane electrodes based on the ionassociates lignocaine‐cobalt thiocynate (I), lignocaine–phosphomolybdate (II) and lingnocaine–reinckate (III) were constructed. The electrodes exhibited linear response over the concentration ranges 0.02–100, 0.01–100 and 0.01–10 mMfor I, II and III, respectively. pH did not effect the electrodes performance within the ranges 3–6, 3–7 and 3–6·5 for 10−2, 10−3and 10−4MLgHCl, respectively. Interferences are negligible for many inorganic cation, sugars and amino acids. The isothermal coefficients were found to be 0·000459, 0·000698 and 0·000404 V °C−1for I, II and III, respectively. The life spans of the electrodes are more than 2 months of continuous work. Potentiometric titration and the standard addition method were used to determine LgGCl in pure solutions and in pharmaceutical preparations wi

ISSN:0268-2575    

DOI:10.1002/jctb.280640410

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe production process forArthrobacter simplexhigh specific hydrocortisone Δ1‐dehydrogenase activity and biomass yield (full experimental plan: 1·5 × 1014experiments). The specific hydrocortisone Δ1‐dehydrogenase activity was improved by a vector of 4·5 to 1800 U g−1. With the optimized medium composition in a stirred tank reactor for batch production ofA. simplex, a specific hydrocortisone Δ1‐dehydrogenase activity of 2000–3000 U g−1dry biomass was achieved depending on harvest time (previously reported d

ISSN:0268-2575    

DOI:10.1002/jctb.280640411

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY