摘要:

AbstractSuspension cultures of tobacco cells were studied using airlift and rotary‐drum bioreactors. The effect of initial concentrations of a major substrate, sucrose, on the growth and production of a secondary metabolite, phenolic compounds, was investigated. The dry weights and total concentrations of the phenolic compounds increased with the initial sucrose concentration in both bioreactors. Both bioreactors were found to have the same tendency for the effect of initial sucrose concentration. The structured model, presented previously was modified by considering that sucrose was hydrolyzed to glucose and fructose by an enzymatic reaction. The previous and the new models were applied to the above two sets of experimental data obtained with two bioreactors, independently. The hydrolysis of sucrose was elucidated to contribute slightly to the overall kinetics of growth and secondary metabolite production in these cultures. Furthermore, the levels of shear damage in each bioreactor were quantitatively compared based on the death rate constant,ki, which is one of the model constant

ISSN:0268-2575    

DOI:10.1002/jctb.280630302

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractDecyl isonicotiniate and decyl nicotiniate permit a rapid extraction of palladium(II) from its hydrochloride solutions. Decyl picoliniate is not a suitable extractant. 4‐Octylphenylamine can act as a phase transfer catalyst when its concentration in the organic phase is at least 2·5 × 10−4M. It seems that the interfacial adsorption of pyridine carboxylates and of 4‐octylphenylamine is not the decisive phenomenon in palladium(II) extraction. The negligible protonation of the pyridine‐type extractants and the phase transfer catalysis explains well the quick extraction of palladium(II) with the commercial and highly hydrophobic extractant ACOR

ISSN:0268-2575    

DOI:10.1002/jctb.280630303

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractSclerotium glucanicumNRRL 3006 was cultivated in a 120 dm3working volume airlift reactor with external recirculation loop for the production of the exopolysaccharide (EPS), scleroglucan. When culture pH was not controlled EPS production, at a range of air flow rates, was poor (<2 kg m−3). Biomass formation generally increased with increasing aeration rate. When culture pH was controlled at 4·5 ± 0·2 EPS production was maximal at an air flow rate of 100 dm3min−1and fell as air flow rate decreased. Operation of the reactor at a high (100 dm3min−1) air flow rate for the early part of the process (up to 96 h), followed by a low air flow rate (20 dm3min−1), led to reduced biomass and oxalate formation, and a slight increase in EPS concentration relative to operation at a constant air flow rate of 100 dm3min−1. EPS production in this pneumatically‐agitated reactor was equal to the highest levels reported in small‐scale stirr

ISSN:0268-2575    

DOI:10.1002/jctb.280630304

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractFluorans are given considerable attention as functional dyes for heat‐and/or pressure‐sensitive recording media. Numerous potential metal complexes were synthesised to prolong the life of coloured species. The protecting effect of these compounds against the photofading was examined on cellulose. It was found that the zinc or nickel salts of 3,5‐dihydroxy‐2‐naphthoic acid and its derivatives can be applied as effective stabilisers against the fading of flu

ISSN:0268-2575    

DOI:10.1002/jctb.280630305

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThermomyces lanuginosusRT9 was grown in a stirred and aerated reactor for the production of xylan‐degrading enzymes and the kinetics of xylanase and β‐xylosidase secretion investigated. During each fermentation,kLadecreased with increasing mycelia concentration to the point of cellular disintegration. Although both agitation and aeration rates had significant influences on the growth rate as well as on the yields and rates of enzymes (xylanase and β‐xylosidase) release, the enzyme secretion kinetics showed a comparable pattern independent of the operating conditions. Enzyme secretion could be separated into a growth phase, during which extracellular xylanase was at low level, and an enzyme release phase, when there was a notable increase in the xylanase production rate accompanying cellular disinte

ISSN:0268-2575    

DOI:10.1002/jctb.280630306

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractAs part of a study to assess the efficacy of impregnation for masonry materials, the impregnation of earth substrates with soluble sodium silicate followed by water‐based silane/siloxane emulsion was investigated. The treatment was found to be successful in achieving water repellent and consolidation effects for the earth substrates. The water repellent effect is developed by the silane/siloxane emulsion which forms a polysiloxane thin film on the capillary wall surface through siloxane bonds. The water repellent effect is greatly enhanced by pre‐impregnation with the silicate. The consolidation of the earth substrate by soluble sodium silicate is caused by the silicate gel formed by crosslinking with the substrate. The water repellent and consolidation effects in the earth substrates have been studied by using water absorption tests and FTIR examinat

ISSN:0268-2575    

DOI:10.1002/jctb.280630307

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractAn insoluble active preparation of pepsin was made by covalent binding of the enzyme to succinylated chitosan through amide bond formation, with carbodiimide as condensing agent. The enzyme retained 80% specific activity and showed greater stability on storage than the soluble enzyme.

ISSN:0268-2575    

DOI:10.1002/jctb.280630308

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractAdsorption of Triton X‐100 on various silica substrates has been investigated. A number of solids, including a natural quartz, this quartz washed with HCl acid and subsequently heated at 1273 K; two aerosils and one Kieselgel silicas were studied. These solids exhibit surface areas in the range of 5 to 430 m2g−1. All the Triton adsorption isotherms display an S‐shape at the adsorption temperatures studied (298 and 308 K). It has been found that the pretreatments of natural quartz (by water washing, impurities removed by acid and/or high temperature calcination) affect considerably the amounts of TX‐100 adsorbed. Measurements of surface composition have been made by X‐ray photoelectron spectroscopy (XPS) with particular emphasis on the presence of impurities and on the number of OH groups at the surface of the samples. The nature of the surface hydroxyl has also been studied by infrared spectroscopy. Furthermore, the specific number of hydroxyl groups on the surface of the silica samples has been determined by thermogravimetric analysis. Finally an attempt to correlate solid surface characteristics with adsorption isotherms has been

ISSN:0268-2575    

DOI:10.1002/jctb.280630309

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractStudies took place to investigate the effects of different nutrient conditions on the biosorption ability and selectivity of heavy metals bySaccharomyces cerevisiae. After having grown in media supplemented with additional glucose, ammonium, phosphate or cysteine, the yeast was exposed to an equimolar solution of lead, cadmium, zinc and copper. Lead removal from a mixed solution was significantly higher than that of copper, followed by zinc and cadmium. Generally, yeasts from cysteine‐rich media showed greatest sorption capacity whereas phosphate addition influenced zinc selectivity. In addition, glucose, fructose and sucrose as carbon sources were examined. Cultures grown in glucose had a better uptake than those cultivated with fructose at an incubation time of 30 mi

ISSN:0268-2575    

DOI:10.1002/jctb.280630310

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractExperimental data for air–water two‐phase co‐current flow in two different pipe diameters were used to test the prediction of pressure drop by a number of existing theories and correlations. Several models are shown to be useful for prediction, particularly with the stratified regimes which have proved difficult to handle in the past. The model suggested by Olujic proved to be of particular

ISSN:0268-2575    

DOI:10.1002/jctb.280630311

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY