摘要:

AbstractA 30‐liter apparatus for growing cells continuously is described. Samples are taken automatically, thus obviating one of the main causes of contamination. In order to eliminate the continuous introduction of a gas stream, the pH was kept constant by means of the injection of NH4OH or NaOH. Under these circumstances, and by means of the two methods of agitation described—rotary and “by Vibromixer”—a quantity of cells of approximately 4 × 1010is harvested every 4

ISSN:0006-3592    

DOI:10.1002/bit.260130402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractHeLa cells have been cultured at different controlled pH levels in batch suspension culture with open gas phase. Continuous monitoring of the dissolved oxygen tension throughout the culture cycle reveals a characteristic pattern of variation which correlates with various aspects of growth and carbohydrate metabolism. The effect of pH, size, and physiological state of the inoculum on this pattern have been determined, and the results are discussed in terms of a theoretical respiratory rate equation.

ISSN:0006-3592    

DOI:10.1002/bit.260130403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractSubstrate inhibited enzyme reactions occurring in systems open to mass transfer may display multiple steady‐state behavior. For a simple one‐substrate case it is shown theoretically that the unstable steady‐state region always lies within the conversion range of 50–100%. A criterion for the stability of a steady‐state point is given. Numerical solutions of the appropriate transient equation show how the system approaches stable steady state in instances where there are three possible steady‐state points. The consequences of the existence of an unstable region on the systems response to changes in its parameters i

ISSN:0006-3592    

DOI:10.1002/bit.260130404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractTwo‐step microbial transformation of 16α‐hydroxycortexolone to its 1‐dehydro‐11α‐hydroxy derivative, without isolating an intermediate, was achieved with an overall yield of 72% of product at a steroid substrate concentration of 3 mg/ml. The process included formation of the cycloborate complex of the substrate, hydroxylation of the borate complex with a suspension ofAspergillus ochraceusmycelium in phosphate buffer, and dehydrogenation of the 11α‐hydroxylated intermediate with acetone‐driedArthrobacter simplexcells. The desired product was then obtained by breaking the resultant borate complex throu

ISSN:0006-3592    

DOI:10.1002/bit.260130405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractThe effect of inorganic nutrients on iron oxidation byThiobacillus ferrooxidanswas studied using a concentration of 2.0 g Fe2+/liter. Besides ammonium‐nitrogen and phosphorus, the essential nutrients were sulphate and magnesium, with the lowest unlimiting concentration being 2.0 g SO 2−4/liter and 2.0 mg Mg2+/liter for a suspension of about 108cells/ml. Omitting nitrate, calcium, potassium, and chloride had no influence on the iron oxidation. Nitrate and chloride were inhibitory in high concentrations although the bacteria were able to adapt to their presence. Several organic compounds tested in 0.5% (w/v) concentrations inhibited iron oxidation. Complete inhibition up to 14 days was caused by fructose, lactose, meat extract, yeast, extract, peptone, and tryptone.T. ferrooxidans‐strains were able to adapt to the presence of organic material even though they were not necessarily able to use the organic compounds for energy. Some general conclusions are made concerning the role of nutrients in leaching pr

ISSN:0006-3592    

DOI:10.1002/bit.260130406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractLiquid phase coefficients were measured for the absorption of oxygen from air to the free interface in stirred vessels. Coefficients for absorption into soft water were independent of the instantaneous dissolved oxygen concentration. Coefficients for absorption into soft water containing a surface active agent were strongly dependent on the instantaneous dissolved oxygen level. The degree of nonlinearity of the coefficients was a function of the rate of agitation of the liquid. The coefficients were independent of the amount of surface active agent added above a very low level. Absorption coefficients for bubble aeration in the same vessels were independent of dissolved oxygen concentration even when the surface active agent was present.

ISSN:0006-3592    

DOI:10.1002/bit.260130407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractThe rates of release of 7 enzymes from bakers' yeast have been measured. The disruption process did not cause loss of activity of these enzymes. The various operating pressures, temperatures, and initial yeast concentrations used did not affect the rates of enzyme release relative to protein release. The release of acid phosphatase and invertase was faster than the overall protein release. Alcohol, glucose‐6‐phosphate, and 6‐phosphogluconate dehydrogenases were released slightly faster or at the same rate as the overall protein and alkaline phosphatase and fumarase were released more slowly. These observations correlate well with the reported locations of these enzymes in the yeast

ISSN:0006-3592    

DOI:10.1002/bit.260130408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractA process method has been developed for estimating rapidly the conversion of 9α‐fluoro‐16α‐hydroxyhydrocortisone to 9α‐fluoro‐16α‐hydroxyprednisolone in fermentation broths. This allows frequent analyses of samples during the fermentation cycle. The absorbance ratio determination of conversion of the steroids is based on the measurement of the absorbance of aqueous steroid borate complexes at 241.

ISSN:0006-3592    

DOI:10.1002/bit.260130409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractA model based on diffusion mechanisms accounts for oxygen transfer from flowing nutrient medium into a film of organisms in slime. Profiles of dissolved oxygen concentration are generated at distances downstream from the start of the slime. In these studies, the nutrient medium was assumed rich, thus the rate of oxygen transport limited microbial respiration. Parameter sensitivity tests were performed for flow rate, oxygen concentration in the medium, and mass transfer coefficients.

ISSN:0006-3592    

DOI:10.1002/bit.260130410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260130411

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY