摘要:

AbstractA temperature‐sensitive cell division cycle mutant ofPenicillium chrysogenumP2 has been immobilized on Celite and grown in a 250–320‐L working volume air‐lift fermenter. The ability to uncouple growth and penicillin synthesis by raising the temperature to 30 °C also overcame the problem of the free cell mass which appeared after 300 h operation with the parent organism. After 500 h operation, penicillin and ACV dimer were still being syn

ISSN:0006-3592    

DOI:10.1002/bit.260360802

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe fluid dynamic design and characterization of a low mechanical stress agitator and bioreactor vessel for large‐scale bioprocessing using anchorage dependent mammalian cells is considered. The complex and fragile nature of mammalian cells puts stringent constraints on the design of agitators for stirred tank bioreactors. Traditional agitators have difficulty meeting the competing requirements of fluidization and mixing while maintaining low enough mechanical stress levels to avoid cell damage. A rotating disc agitator design is proposed. Flow visualization and laser Doppler velocimeter measurements reveal fluidization of microcarriers with a gentle (low turbulence level), highly three‐dimensional flow characterized by good mixing at low hydrodynamic shear stress lev

ISSN:0006-3592    

DOI:10.1002/bit.260360803

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

年代:1990

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260360804

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

年代:1990

数据来源: WILEY

摘要:

AbstractWhen a mechanism is used to determine possible deactivation kinetics, a certain consistency with the kinetics of the main reaction is found. This result is examined in the light of experimental evidence obtained with bovine liver andAspergilluscatalases.

ISSN:0006-3592    

DOI:10.1002/bit.260360805

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

年代:1990

数据来源: WILEY

摘要:

AbstractIn order to produce a product with a high content of maltotetraose, dual‐enzyme systems composed of immobilized maltotetraose‐forming amylase (G4‐forming amylase) and pullulanase were studied. The thermostability of individually immobilized enzymes was examined in continuous operation; studies revealed that the enzyme immobilized on “Chitopearl” was much more stable than that immobilized on Diaion HP‐50. The effects of operating conditions on the stability of G4forming amylase immobilized on “Chitopearl” were examined to confirm that the apparent half‐life data could be arranged using the immobilized enzyme stability factor,fs. As for the dual immobilized enzyme system, six methods of usage were considered, with five yielding a 7–10% (w/w) higher content of maltotetraose product than the single‐enzyme system. The effects of operating conditions on the maltotetraose production reaction were examined to confirm that the maltotetraose content of the products could be analyzed using the specific space velocity,SSV. In dual immobilized enzyme systems, pullulanase immobilized on the same carrier as the G4‐forming amylase was found to be more stable than pullulanase immobilized on separate carriers. The effectiveness of using immobilized pullulanase along with the G4‐forming amylase was confirmed from constant‐conversion operations in which the maltotetraose content in the product was kept at 50% (w/w) in labor

ISSN:0006-3592    

DOI:10.1002/bit.260360806

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe growth of two lymphocyte cell lines, a hybridoma cell line and a human cutaneous T cell lymphoma (HuT78), was studied in fed‐batch culture, and unstructured models of growth developed. A criteria was established to insure that the growth rate varied by less than a specified tolerance throughout the culture period. Glutamine and serum were growth‐limiting nutrients for both cell lines with half‐maximal growth rates at 0. 53 mMglutamine and 0. 55%(v/v) serum for the hybridoma cells and 0. 21 mMglutamine and 1. 5% serum for the HuT‐78 cells. Over the range of glucose concentrations from 5. 5 mMto 28 mM, the specific growth rate of hybridoma cells was independent of glucose concentration, whereas glucose concentrations above 5. 5 mMinhibited HuT‐78 growth. For both cell lines, the growth rate was significantly inhibited by the addition of ammonium, although the hybridoma cell line was more affected by ammonia than was the HuT‐78 cell line. Growth of HuT‐78 cells increased in the presence of interleukin‐2. Unstructured models for the hybridoma cells were similar to other models presented in the literature. Applications of these models to adoptive immunotherap

ISSN:0006-3592    

DOI:10.1002/bit.260360807

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe evolution of the activity of the general amino acid permease and ethanol and glucose concentrations in the medium were studied in a mild fermentation process carried out by a wine strain ofSaccharomyces cerevisiaevar.ellipsoideusisolated from grape musts in spontaneous fermentation. The cells displayed a reduction in the activity of the general amino acid permease parallel to the increase of ethanol in the medium. This ethanol increase was not enough to promote a substantial inhibition on the total polypeptide synthesis measured as polyuridylic‐acid‐directed polyphenylalanine synthe

ISSN:0006-3592    

DOI:10.1002/bit.260360808

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

年代:1990

数据来源: WILEY

摘要:

AbstractA polyethylene‐g‐acrylic acid (PE‐g‐AA) graft copolymer was prepared via gamma‐ray‐irradiation‐induced postirradiation procedures, and was used as support material for the immobilization of glucose oxidase. Soluble carbodiimides were used as the coupling agent. Reasonable yields were obtained with CMC but not with EDAC, EEDQ, or WRK. A number of factors were studied. (1) The use of water‐soluble carbodiimides as condensing agent was attempted and the optimum condition for coupling glucose oxidase to PE‐g‐AA was established; (2) the effect of pH and temperature on the reactivity of native and immobilized glucose oxidase was studied. When exposed to temperatures in excess of 60 °C, the immobilized glucose oxidase was less sensitive to thermal inactivation than the native enzyme. The optimum pH value for the performance of the enzyme‐immobilized membrane was 5. 6. For 200 tests, the response error of glucose sensor was less than 4% and its linear detected range was 0–1000 ppm. The obtained glucose oxidase‐immobilized PE‐g‐AA membranes were kept in pH 5. 6 acetate buffer solution at 4 °C. The glucose oxidase activity of the membrane was determined at sevenday intervals. The membranes still have 92% glucose oxidase activity ev

ISSN:0006-3592    

DOI:10.1002/bit.260360809

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

年代:1990

数据来源: WILEY

摘要:

AbstractIn Part l, the process utility of a thermotolerant methylotrophic bacterium is evaluated in chemostat culture under conditions where methanol, methanol/formaldehyde mixtures and dual methanol/ammonia limitation occurred. The results show that the bacterium studied was nonfastideous under steady‐state operation, in contrast to results obtained in batch culture. For application in industrial wastewater treatment processes the bacterium should be employed in systems where the biomass residence time exceeds 5 h, i. e., dilution rates

ISSN:0006-3592    

DOI:10.1002/bit.260360810

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

年代:1990

数据来源: WILEY

摘要:

AbstractIn Part II, the process utility of a thermotolerant methylotrophic bacterium is evaluated with respect to its dynamic response when various substrate or nutrient pulses are imposed on it while growing under steady‐state conditions in a chemostat. The pulses investigated were methanol pulses on methanol‐, methanol/formaldehyde‐, and dual methanol/ammonia‐limited cultures and an ammonia pulse on a severely nitrogen (ammonia)‐limited culture. The results obtained, although exemplifying the complex biochemistry of such bacteria, clearly demonstrate the bacteriums flexibility and versatility in handling process transients. Its lack of fastidiousness in unsteady state continuous culture make it a most promising candidate for inclusion in process cultures for elevated temperature industrial wastewater

ISSN:0006-3592    

DOI:10.1002/bit.260360811

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

年代:1990

数据来源: WILEY