摘要:

AbstractAlthough land pollution is a major environmental concern it is probably the least understood source of pollution in terms of both transport of toxins and remediation. This paper deals with the current situation in legislation and land pollution remediation and highlights future requirements.

ISSN:0268-2575    

DOI:10.1002/jctb.280600302

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe models available to describe lactic acid production do not seem to fit the experimental data very well, especially at the end of batch cultures. From a careful analysis of batch data, an unstructured model of the process has been derived, in which the specific growth rate variations and lactic acid concentration with time have been described by complemented logistic functions. Also, an additional term has been introduced into the Luedeking–Piret expression, taking into account the reduction in rate of lactic acid production observed at very low growth rat

ISSN:0268-2575    

DOI:10.1002/jctb.280600303

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe effects of various medium carbon sources and salt solutions on the production of β‐glucosidase (βG, EC 3.2.1.21) byAspergillus nigerhave been studied. β‐Glucosidase productivity was found to be 50 times greater than that reported previously.1This higher productivity was achieved by employing a mutant strain of the organism, readily available and inexpensive carbon sources, such as cellulose and orange peel, and a simple nutrient salt so

ISSN:0268-2575    

DOI:10.1002/jctb.280600304

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractA detailed commercial process for the synthesis and purification of the activated disaccharide, α‐D‐cellobiosyl bromide heptaacetate (1) was developed. Reaction of α‐D‐cellobiose octaacetate (CBO) with HBr in glacial acetic acid or in glacial acetic acid/methylene chloride combination affords α‐D‐cellobiosyl bromide heptaacetate in high yield and excellent quality. Process variables such as reaction solvent, reaction time, reaction temperature, HBr stoichiometry, isolation methods and product purification options were optimized for large‐scale synthesis. α‐D‐Cellobiosyl bromide heptaacetate was successfully prepared in a commercia

ISSN:0268-2575    

DOI:10.1002/jctb.280600305

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractSome novel sulfonate ester‐containing mono‐, bi‐ and tricyclic fused ring systems (IV, Xa,b, XIa,b, XIVandXV) together with their precursorsI, IIandIIIwere synthesized with a view to evaluating their efficacy as new sulfur‐containing fungitoxic agents. The structures of the named compounds were established from elemental and spectral a

ISSN:0268-2575    

DOI:10.1002/jctb.280600306

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractA supported liquid membrane system was investigated for the carrier mediated transport of phenylalanine to more fully understand the contradictory effects, described in the literature, of chloride ion concentration in the aqueous phases on the stability of the system. The role of the organic phase and its interaction with carrier and support material was considered. The carrier mediated transport was comparable to an enzyme mediated process. Kinetic studies were undertaken and the data interpreted in a manner appropriate to biological transport processes to consider the transport process at a molecular level. The system was shown to deviate from a direct 1: 1 exchange process between phenylalanine and chloride and had a high degree of selectivity with respect to phenylalanine.

ISSN:0268-2575    

DOI:10.1002/jctb.280600307

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractAnalysis of the growth ofPseudomonas cepaciaG4 on phenol in continuous culture has been carried out. The data were checked for consistency using both available electron and carbon balances. Coupled with the covariate adjustment estimation technique, the best estimates for true biomass energetic yield, ηmaxand maintenance,me, were obtained when the carbon dioxide measurements were excluded. However, upon making corrections to the gas measurements, the best estimates were the maximum likelihood estimates (MLE) based on the complete data. The method therefore allows discrimination to be made between data. Also, similar estimates were obtained using Pirt's model based on the Monod approach and a modified form based on substrate uptake rate being the limiting factor. For the aerobic growth ofP. cepaciaG4 on phenol, ηmax= 0·417 andme= 0·0513 h−1were obtained when the CO2data were excluded. When corrections were made to the gas measurements to take into account the dissolved CO2and the effect of operating temperature, ηmax= 0·432 andme= 0·0684 h−1were obtained. From the 95% confidence intervals, a maximum of about 38–47·5% of the energy contained in phenol is incorporated into the biomass while the balance (52·5–62%) is evolved as heat with only a little energy needed for the maintenance

ISSN:0268-2575    

DOI:10.1002/jctb.280600308

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractStyrene alkylmethacrylate succinimide phosphoric acid additives are synthesised and evaluated for use in multigrade crankcase lubricating oils as multifunctional viscosity index improvers having both antioxidant and dispersant properties. The synthesis is based on reacting styrene alkylmethacrylate (prepared by the reaction of styrene and 2‐ethylhexylmethacrylate at different styrene/methacrylate mole ratios under various reaction conditions) with maleic anhydride and tetraethylenepentamine in the presence of phosphoric acid. Comparative evaluation of the properties of the synthesised products (e.g., viscosity properties, shear stability, oxidation stability and dispersive power) with commercial additives showed they were suitable for use as viscosity index improver

ISSN:0268-2575    

DOI:10.1002/jctb.280600309

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe stability and proteolytic activity of papain were studied in reverse micellar systems, and in aqueous media. In reverse micelles the maximum activity obtained was 80% of the enzyme activity in aqueous solution. Higher papain stability was found in reverse micellar systems compared with that in aqueous solution with half‐lives of 24 and 10 days respectively. Electron spin resonance (ESR) spectroscopy studies of aqueous and reverse micellar systems were performed in an attempt to explain the observed enzyme stability and activity profiles. For this purpose a spin label—TEMPOacetamide—was covalently linked to the Cys‐25 residue of the papain active center. ESR spectra of labeled papain indicated that catalytic activity of papain could be related to the conformational rigidity near the reaction center. The lower activities obtained in reverse micelles could be a result of the greater degree of mobility and polarity observed in these systems, which can be attributed to papain unfolding. The greater stability found for papain in reverse micelles could be the result of the limited extent of this denaturing process owing to the organized surfactant molecules around the

ISSN:0268-2575    

DOI:10.1002/jctb.280600310

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractA comparison was made of the hydrolysis of microcrystalline cellulose Avicel using the cellulolytic complex of the ascomyceteMorchella conicaand a commercial cellulase. An enzyme concentration of 1 U AVase mg−1substrate gave the best results during the hydrolytic processes. At 24 h, theM. conicaenzyme complex achieved 35.5% and the commercial cellulase 31·2% saccharification, with glucose 84·2% and 52% of the total reducing sugars liberated, respectively. The specific rates of hydrolyses were 0·77 and 0·14 h−1for reducing sugars and 0·54 and 0·12 h−1for glucose formation withM. conicaand the commercial cellulase, respectively. At 96 h, the degree of saccharification reached 46% forM. conicaand 49% for the commercial cellulase, with glucose 76·5% and 65·9% of the total reducing sugars liberated, respectively. Both the complexes were quite stable with a residual activity of 62% CMCase and 47% AVase forM. conica, and 74% CMCase and 57% AVase for the commercial cellulase at 96 h of hydrolysis. The qualitative analysis of the hydrolysis products by TLC indicated, forM. conica, an earlier appearance of cellobiose, which was quickly hydrolyz

ISSN:0268-2575    

DOI:10.1002/jctb.280600311

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY