摘要:

AbstractContinuous whey fermentation by Kluyveromyces fragilis was studied in a 30‐dm3stirred fermenter as a function of the dilution rate (D) and feed concentration of lactose (So). By using the concept of material and energy balances, it was possible not only to check the consistency of the experimental steady‐state responses, but also to develop an unstructured model based on a Monod‐type kinetic equation for cell growth and two independent linear equations for the consumption rates of lactose and oxygen. Moreover, a typical Lineweaver—Burk plot enabled the yeast specific growth rate to be described as that of an enzyme‐catalysed reaction in the presence of an unknown noncompetitive inhibitor (that was identified with a reference intermediate compound produced by the microorganism itself under partially anaerobic conditions and expressed in terms of ethanol equivalent). In this way, the experimental cell concentrations were reconstructed with a mean standard error of about 10%, thus confirming the capability of this model to provide a reliable basis for further scale‐up of this fermentat

ISSN:0268-2575    

DOI:10.1002/jctb.280490302

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractA methane fermentation system can be considered as a multi‐objective optimization problem characterized by conflicting objectives such as investment cost, net biogas production and chemical oxygen demand (COD) removal. To this end, a k‐objective ‐constraint method was used to determine the optimal design and operation parameters of a continuously stirred anaerobic digester. This equipment treats leachates from the controlled solid urban wastes landfill at Garraf (Barcelona, Spain), which receives 5–6 × 105tonnes of wastes per year. The optimal solutions were generated for two design criteria: (a) reduction of cost to a minimum and (b) maximization of net energy production with at least 75% removal of COD. The preferred solution was obtained by using the non‐inferior so

ISSN:0268-2575    

DOI:10.1002/jctb.280490303

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractA process for large‐scale purification of staphylococcal enterotoxin B (SEB) is presented. The process consists of three chromatographic steps. The first two steps are based on ion‐exchange chromatography and the final one on gel filtration.Diluted culture supernatant (2000 dm3) with a SEB content of 0.4 mg dm−3were processed and purified. SEB was obtained in 1.5 dm3of 0.1 mol dm−3ammonium hydrogen carbonate buffer, pH 8.0. The final product produced a single band on SDS polyacrylamide gel electrophoresis and a single peak when subjected to analytical gel filtration. The overall recovery

ISSN:0268-2575    

DOI:10.1002/jctb.280490304

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

Abstract5‐Aryl (or alkyl)‐8‐hydroxyquinoline‐7‐sulphonic acids have been prepared by the Mannich reaction of 8‐hydroxyquinoline‐7‐sulphonic acid with primary and secondary amines. Their bactericidal activities have

ISSN:0268-2575    

DOI:10.1002/jctb.280490305

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe copper amalgam electrode can be used for clean oxidative coupling of but‐1‐yn‐3‐ol in good yield. An electrochemically generated intermediate can be further coupled in a solution process by aeration of the electrolyte giving increased yields. Addition of pyridine depresses coulombic yields in the electrochemical system, although it increases the rate of the purely chemical

ISSN:0268-2575    

DOI:10.1002/jctb.280490306

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractBased on the glucose oxidase‐β‐galactosidase sequence an enzyme probe for the specific determination of lactose has been developed. β‐Galactosidases from different sources have been compared, the sensor containing β‐galactosidase from Curvularia inaequalis has been characterized in respect of optimal pH, enzyme loading, apparent activity and functional stability. The response of the bi‐enzyme probe depends linearly on lactose concentration between 0.02 and 3.00 mmol dm−3. The application to different milk and foodstuff samples resulted in good correlations toward enzymatic photometric (y = (0.956x‐1.67) mmol dm−3) and infrared detection (y = (1.0772x‐0.3909)%). Using a measuring frequency of 100 h−1the serial imprecision is about 2% for diluted milk, urine

ISSN:0268-2575    

DOI:10.1002/jctb.280490307

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe extraction and stripping of Co(II), Ni(II), Cr(III) and Fe(III) from aqueous solutions by rosin dissolved in toluene has been investigated. Results obtained show that rosin is better extractant than abietic orn‐lauric acids under comparable conditions.From these results, and the data of Mn(II) solvent extraction studied previously under the same conditions, a separation and concentration process for these five cations in aqueous solutions has been designed. Saturated solutions of Fe(III), Cr(III), Mn(II) and finally Co(II) and Ni(II) have been obtained successively by extraction and stripping, by addition of ammonium hydroxide to obtain the appropriate pH value, and by modifying adequately the organic phase/aqueous phase volume rati

ISSN:0268-2575    

DOI:10.1002/jctb.280490308

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

Abstract4‐Phenyl‐5‐aminopyrazole2obtained from phenylcyanoacetaldehyde1and hydrazine hydrate reacted with diethyl malonate to give 3‐phenyl‐5,7‐dioxopyrazolo[1,5‐a]pyrimidine3, used as the key compound in the synthesis of arylazo dyes. The key compound3was coupled with various aryldiazonium salts4to yield 3‐phenyl‐7‐hydroxy‐6‐arylazopyrazolo[1,5‐a]pyrimid‐5‐ones5.The resulting arylazo dyes(5)were refluxed in phosphorus oxychloride to give 3‐phenyl‐5,7‐dichloro‐6‐arylazo‐pyrazolo[1,5‐a]pyrimidines6, which subsequently reacted with refluxing morpholine and piperidine to yield 3‐phenyl‐5,7‐bis(morpholino and piperidino)‐6‐aryiazopyrazolo[1,5‐a]pyrimidines7.The arylazo dyes5 and 7were applied to polyester fibres as disperse dyes and the arylazo dyes6were applied to polyamide fibres as disperse reactive dyes. The

ISSN:0268-2575    

DOI:10.1002/jctb.280490309

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractAn energy‐economic use of reaction heat is possible only if thermophilic microorganisms convert carbon substrates into biomass at temperatures above 65°C.The thermophilic bacterium Bacillus stearothermophilus TP5 was isolated from a man‐made hot water reservoir. The highest specific growth rate of 1.6 h−1was obtained in continuous cultivation (chemostat) on a glucose‐containing nutrient medium at 68°C, pH 6.8 and normal pressure. The highest values for the biomass production rate (3.2 g dm−3h−1) and the biomass yield coefficient (0.39 gg−1) were obtained at a dilution rate of 1.3 h−1(about 80% of the highest specific growth rate) under the above‐mentioned conditions. The biomass production rate of the thermophilic bacterium was higher in the chemostat than in the semicontinuous process at normal pressure. The biomass produced in the chemostat at a dilution rate of 0.4 h−1contained 71% of protein and 8% of RNA and had an ash content of 6%. The optimum and maximum temperatures of growth were changed by raising the pressure inside the reactor.As a prerequisite for the energy‐economic use of the reaction heat, the specific heat production was determined by using a special calorimeter. The ratio of heat production to oxygen consumption (oxy‐caloric coefficient) was found to be 13.6 kJ g−1, which is close to the theoretical value deduced from mass

ISSN:0268-2575    

DOI:10.1002/jctb.280490310

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

ISSN:0268-2575    

DOI:10.1002/jctb.280490311

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY