摘要:

AbstractRepeated‐batch fermentations of glucose to ethanol byZ. mobilis(ATCC 10988) were examined in two semi‐defined nutrient media. The measurement of acid produced by the microorganism was used to study its transient fermentation characteristics. An examination of the inhibitory effect of ethanol in repeated‐batch fermentations supports an earlier finding on the presence of a ‘slow‐acting inhibitory mechanism’ at high ethanol concentration inZ. mobilis(ATCC 10988) cultures. The experimental results also suggest that both microbially produced and exogeneously added ethanol have similar inhibitory effects on the fermentation behavior of thi

ISSN:0268-2575    

DOI:10.1002/jctb.280470102

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe adsorption processes ofp‐toluidine,p‐bromoaniline andp‐acetylaniline, from aqueous solution at 20°C, on heat‐treated sepiolite have been studied. With regard to the kinetic study, the processes have resulted in being second order in relation to the vacant active centres of the sepiolite, the highest value of the specific rate constant corresponding to thep‐acetylaniline and the lowest one to thep‐toluidine. The adsorption isotherms may be classified as L‐type (Giles classification) and the values of the adsorption capacity have been calculated from the Langmuir equation applied to the experimental data points. The highest values of the adsorption capacity and specific surface area also correspond to thep‐acetylaniline, and the lowest ones t

ISSN:0268-2575    

DOI:10.1002/jctb.280470103

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractUltrafiltration was used in a one‐step method to purify and concentrate biosurfactants—surfactin and rhamnolipids—from culture supernatant fluids. The ability of surfactant molecules to form micelles at concentrations above the critical micelle concentration allows these aggregates to be retained by relatively high molecular weight cut‐off membranes. Lower molecular weight impurities such as salts, free amino acids, peptides and small proteins are easily removed. Various molecular weight cut‐off membranes were examined for the retention of surfactin and rhamnolipids (mol. wts 1036 and 802 respectively). Amicon XM 50 was the superior membrane for retention of surfactin and a 160‐fold purification was rapidly achieved. The YM 10 membrane was the most appropriate for rhamnolipid recovery. Ultrafiltration can play an important role in biosurfactant purification as large volumes of media can be processed rapidly at extreme

ISSN:0268-2575    

DOI:10.1002/jctb.280470104

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractTannin, which contains polyhydroxy groups, has a high affinity for uranium. Various tannin–protein complexes were prepared to develop new adsorbents for uranium recovery from seawater. Albumin tannate has a high ability to adsorb uranium from seawater. Tannin was immobilized on matrices which have multiple active amino groups, such as aminopolystyrene and poly(vinyl‐4,6‐diamino‐s‐triazine)—poly VT. Of these complexes, tannin immobilized on poly VT adsorbed uranium most efficiently from seawater and highly selectively from a solution containing various heavy metals; the uranium adsorption was very rapid and was pH dependent. This adsorbent therefore appears to have potential for use in a commercial process for uranium recovery from seawater or from uranium‐containin

ISSN:0268-2575    

DOI:10.1002/jctb.280470105

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractSynthesis of 2‐(hetaryl or aryl)‐azo thiophene derivatives (IVa–IVg) was achieved by diazotisation of ethyl 2‐amino‐3‐cyano‐5‐carbethoxy thiophene‐4‐acetic acid ester (I) using nitrosyl sulphuric acid, coupling with suitable heterocyclic hydroxy and N, N‐dialkyl‐substituted aryl amines, which resulted in thiophene azo dyes. The key intermediate (I), used as the diazonium component was synthesised in one pot and in excellent yield from diethyl acetone dicarboxylate, sulphur and malononitrile, using diethylamine as a catalyst, following the Gewald Synthesis. The spectral properties of these dyes were studied. The dyes when applied as disperse dyes on polyester fibres

ISSN:0268-2575    

DOI:10.1002/jctb.280470106

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractA process has been proposed for the treatment of apatite concentrate obtained from the dephosphorization of iron ore. In this process, the apatite is acidulated by HNO3to produce high‐purity H3PO4. The crude acid obtained is shown to be at least equivalent to, if not better than, the typical wet‐process acid. The H3PO4is purified by extraction and concentrated by evaporation. The spent HNO3is regenerated by H2SO4to precipitate gypsum. Rare earths dissolved during the apatite acidulation are recovered by precipitation with oxalic acid. The process is to be integrated with the processing of the solutions obtained from the direct leaching of iron ore (the phosphorus removal) with HNO3. The integrated process is more economical than the single treatment and also it offers the flexibility of producing both sinter‐fines and pellets to meet demand in steel manufa

ISSN:0268-2575    

DOI:10.1002/jctb.280470107

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractHeavy alkylated benzene, which is accumulated as a by‐product from linear alkyl benzene synthesis, was evaluated as a starting material for anionic liquid sulphonate surfactants.Chemical structure analysis by GC/MS showed that the by‐product contains eight different paraffinic side‐chains, within the carbon range C12–C15. Accordingly, sulphonation conditions for it were adjusted to optimize the reaction yield and product quality.Liquid surfactant formulations based on these anionic sulphonates were established by incorporating other necessary ingredients. The formulations developed have shown high efficiency as detergents, wetting agents and emul

ISSN:0268-2575    

DOI:10.1002/jctb.280470108

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractMost studies on 2,3‐butanediol production by microbial fermentation have been carried out usingKlebsiella oxytocaandBacillus polymyxa. In these fermentations there is a significant conversion of carbon source into ethanol, glycerol and various organic acids as by‐products. On the other hand, this investigation has shown that the major products of fermentation byBacillus amyloliquefaciensare 2,3‐butanediol and some minor acids. In a typical fermentation about 33 g of butanediol was produced from 100 g of glucose.The effect of pH, various carbohydrate source, initial glucose concentration and aeration on the 2,3‐butanediol fermentation byB. amyloliquefacienswere investigated. The butanediol productivity and yield was found to be highest with glucose as the carbohydrate source. The glucose concentration was varied between 30 and 100 g dm−3with oxygen transfer rate controlled between 47.5 and 78.0 h−1. Oxygen and the initial substrate concentrations significantly influence the yield, productivity and by‐prod

ISSN:0268-2575    

DOI:10.1002/jctb.280470109

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

ISSN:0268-2575    

DOI:10.1002/jctb.280470111

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

ISSN:0268-2575    

DOI:10.1002/jctb.280470112

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY