摘要:

AbstractTularaemia is a disease caused by the facultative intracellular bacteriumFrancisella tularensis. Vaccination resulting in protective immunity is induced by live vaccine only. Such vaccination can be performed by scarification utilizing the live vaccine strain ofF. tularensis (F. tularensisLVS), which results in good but not complete protection. Humoral as well as cell‐mediated immunity are induced by vaccination and it has been shown that cell‐mediated immunity is a prerequisite for protection. Since the live vaccine strain is attenuated and the genetic background of attenuation is unknown it is important to consider process parameters so that the immunogenicity of the vaccine is preser

ISSN:0268-2575    

DOI:10.1002/jctb.280590402

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractA respirographic biosensor is presented that is capable of monitoring the waste load and potential toxicity of wastewaters, both off‐line in a laboratory or on‐line at the wastewater treatment plant. The principles of the sensors' operation have been developed and implications of the design choices evaluated. Short term BOD values were obtained every 30 min. The linear dynamic range spanned concentrations differing by a factor of 5000. This range could be expanded by a factor of 10 by adjusting the aeration rate of the bioreactor in the sensor. The response time for toxicity detection was approximately 1 h. The use in the sensor of activated sludge from the plant concerned ensured relevant toxicity information was obtained. To check the condition of the sludge, an independent respiration measurement is proposed. When a siginificant activity change is observed, the sludge in the sensor must be replaced. The presence of oxidoreduction chemicals can cause interferences that may lead to measurement errors. Based on a difference in reaction kinetics, their presence can be assessed and the effect eliminated. Both on‐line and laboratory applications in the chemical industry are presented. Special emphasis is given to the usefulness of the sensor data for waste management of production divisions. On‐line assessment of load variations and hydrogen peroxide spills are given as illustrations of the implementation of the sensor on the treatment plant. Attention is drawn to the potential application of the data for process control and improved performance of the treatmen

ISSN:0268-2575    

DOI:10.1002/jctb.280590403

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractAcidic nickel‐bearing solution containing iron, cobalt, manganese, zinc and copper was processed through a solvent extraction and precipitation technique to obtain a pure nickel sulphate solution. Iron was extracted using 0.2MCyanex‐272 (partially neutralised) as the extractant. Stripping of iron from the loaded organic has also been studied. After iron recovery through solvent extraction the raffinate still contained 0·25 g dm−3of iron which was quantitatively separated by a lime precipitation technique. During this iron precipitation there was no loss of cobalt and nickel but copper, manganese and zinc were coprecipitated to some extent. From the iron‐free nickel sulphate solution the other impurities were extracted using the same extractant (Cyanex‐272) in a single stage. The metal ions from the loaded organic were stripped using a 0·5% (v/v) H2SO4solution in a single stage. The entire operation needs only seven stages: two stages for iron extraction, three stages for iron stripping from the loaded organic, and one stage each for extraction and stripping of other impurities. In the entire operation the loss of nickel was les

ISSN:0268-2575    

DOI:10.1002/jctb.280590404

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe study concerns the immobilization of a pectinlyase (PL, EC 4.2.2.3) purified by means of a commercial enzyme for its possible applications in fruit juice and beverage processing. Results previously obtained were improved by employing polyamides, i.e. nylon 6 and nylon 11, activated by easy to perform and inexpensive methods such as direct activation with glutaraldehyde and alkylation with dimethylsulphate followed by treatment with amines and glutaraldehyde. The nylon 6 activated with glutaraldehyde gave an activity of the immobilized PL of about 200 U g−1(at optimum pH) and a half‐life of about 190 h (at pH 3·3 and 2

ISSN:0268-2575    

DOI:10.1002/jctb.280590405

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractAmmonia is produced during anaerobic digestion of protein‐containing materials. While ammonia can be utilized by some members of the anaerobic population, excess ammonia can inhibit methanogenesis. High‐solids anaerobic digestion may be especially sensitive to the effects of ammonia overproduction. This study explored the performance of a pilot scale high‐solids anaerobic digestion process under various total ammonia nitrogen (TAN) concentrations. In general the high‐solids digester could operate up to 1000 mg dm−3without any inhibitory effect. The digester performed best when it was operated at TAN concentrations in the narrow range of 600 to 80

ISSN:0268-2575    

DOI:10.1002/jctb.280590406

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe cerium‐catalyzed syntheses of hydroxybenzaldehydes from cresols by oxygen oxidation have been developed. When cerium catalysts four‐coordinated by hydroxo ligand was employed, the oxidation process required much less catalyst (0·5%), a shorter reaction time (5→2 h) and a lower temperature (120→40°C). The rate of two first‐order reactions increased by a fact

ISSN:0268-2575    

DOI:10.1002/jctb.280590407

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe kinetics of zinc adsorption on charcoal was carried out. In order to study the kinetics of adsorption various parameters were studied such as pH, particle size of charcoal, temperature, amount of charcoal as well as initial Zn2+ion concentration. The adsorption kinetics followed a Freundlich adsorption isotherm. Good correlation of the theoretical and experimental equilibrium concentrations of Zn2+ions was observed for the isotherm model. A mathematical model was developed to explain the kinetic data. The rate determining step for adsorption was found to be diffusion controlled.

ISSN:0268-2575    

DOI:10.1002/jctb.280590408

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractTo confirm the applicability for the extraction of penicillin G by an emulsion liquid membrane (ELM), the degree of decomposition of penicillin G during extraction was theoretically calculated. Decomposition was less than 1% provided that the initial sodium carbonate concentration in the internal phase was correctly determined, which proved the applicability of the ELM process. The procedure to determine the initial carbonate concentration in the internal phase was also described in order that the pH in the internal phase should be within the relatively stable range for penicillin G at the end of the extraction.

ISSN:0268-2575    

DOI:10.1002/jctb.280590409

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractPenicillin G extraction by an emulsion liquid membrane (ELM) was investigated. The effects of surfactants, diluents, and carrier mixtures, together with their combined effects on the initial extraction rate and the emulsion stability were examined. Surfactants, diluents, and carriers used were Span80 (sorbitan monooleate)/ECA4360J (nonionic polyamine),n‐butyl acetate/kerosene, and DOA (dioctylamine)/Amberlite LA‐2 (secondary amine), respectively. The optimum extraction conditions were found to be 20% (v/v) of Span80 in ECA4360J as a surfactant, kerosene as a diluent and Amberlite LA‐2 as a ca

ISSN:0268-2575    

DOI:10.1002/jctb.280590410

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractKluyveromyces fragilis(NCIM 3217),Kluyveromyces marxianus(NCIM 3231),Hansenula polymorpha(NCIM 3377),Pichia fermentan(NCIM 3408),Pichia polymorpha(NCIM 3419) andDebaryomyces castellii(NCIM 3446) were grown on an inulin‐based growth medium. OnlyK. fragilisproduced extracellular inulinase with a maximum after 36 h of growth at 25–27°C. Sucrose and fructose were weak inducers of inulinase as compared to inulin whereas with glucose the inulinase level was minimal. An aqueous extract of chicory roots containing 1% fructan was a better carbon source than inulin and peptone was the best nitrogen source for the production of inulinase. The maximum yield of inulinase was about 7 units cm−3of medium. The invertase to inulinase ratio of 10 in the culture filtrate was reduced to 1·6 on purifying inulinase by ethanol precipitation followed by chromatography on Sephadex G‐200, DEAE‐cellulose and CM‐cellulose columns. Using this purification procedure, inulinase was purified 26‐fold. With inulin as substrate, the shape of the velocity curve was nearer to a sigmoidal pattern whereas with sucrose the curve was hyperbolic. The molecular weight of inulinase was determined as 250 ± 10 kDa. The crude and purified inulinase preparations did not release sucrose or oligosaccharides from inulin, indicating that the enzyme has primarily exo‐inulinase activity. Using the metal‐link chelation method, 40% of inulinase was immobilised on cellulose. Maximum activity of crude, purified and immobilised inulinase preparations was observed at 55°C. The half‐life of immobilised inuli

ISSN:0268-2575    

DOI:10.1002/jctb.280590411

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY