ISSN:0006-3592    

DOI:10.1002/bit.260260802

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe Upjohn Company uses filtration to remove microorganisms and particulates from air and other gases which may come in contact with sterile products. To validate the microbial retentivity of these filters, they were challenged with an aerosol ofBacillus subtilisvarnigerspores. An aerosol challenge was used because it more closely simulated the use for which these filters were designed. The test apparatus was constructed of autoclavable components using a jet‐type nebulizer and heated air mixing tube. Characterization of the aerosol particle size distribution with a particle size analyzer demonstrated that 80% of the particles had a diameter of × 3.0 times;m and that the particles had a mean mass diameter of 1.9 times;m with a geometric standard deviation of 1.8 times;m. Studies conducted with aerosols ofBacillus subtilisvarnigerspores demonstrated that the test apparatus could recover ca. 50% of the spores that were aerosolized. Hydrophobic filters from various manufactures were challenged with an aerosol of at least 108spores ofBacillus subtilis. All filters tested could retain at least 109spores when physical integrity of the filter was verfie

ISSN:0006-3592    

DOI:10.1002/bit.260260803

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

年代:1984

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260260804

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

年代:1984

数据来源: WILEY

摘要:

AbstractThis article presents several characteristics of a state‐of‐the‐art fermentation air filter. The filter medium is composed solely of PTFE and has an absolute pore size rating of 0.2 μm. Quantitative bacteria and bacteriophage retention is shown based on live organism challenge tests. A nondestructive filter test, correlated to the microorganism challenge tests and called the Forward Flow Integrity Test, is described. This test has a sensitivity of one part in 1012and can be performedi

ISSN:0006-3592    

DOI:10.1002/bit.260260805

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe continuous slow feed of animal and vegetable oils is frequently found to be an economically attractive method for maintaining antibiotic fermentations at a highly productive rate. The sterilization of oil feeds can present a major problem in the production plant. In this article, we present data and methodology on the kinetics of the thermal sterilization of No. 2 lard oil and soybean oil. It was also determined that dry heat sterilization condition could occur if dry spores were added to dry oil. This condition could only be partially alleviated by the addition of water to the oil. The theory and design of a small tubular coil continuous sterilizer for sterilizing oils at the point of use is also presented. This type of sterilizer is economical and versatile and simplifies control and instrument requirements. It provides a realistic alternative to the use of sterile feed tanks and sterile headers.

ISSN:0006-3592    

DOI:10.1002/bit.260260806

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

年代:1984

数据来源: WILEY

摘要:

AbstractMicroscopic leaks in fermenter cooling coils were identified as the source of chronic fermentation contaminations. Methods used to identify the problem in production fermenters are described. Recommendations for upgrading quality control criteria for new installations are presented.

ISSN:0006-3592    

DOI:10.1002/bit.260260807

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

年代:1984

数据来源: WILEY

摘要:

AbstractProper design of fermentation facilities and equipment modification can control the risks associated with largescale production and purification of microbially produced cytotoxic agents and oncogenic viruses. The primary biohazard risks to operators and the environment are generation of aerosols and accidental spills. Fermentation and recovery facilities can be constructed to contain these agents by installing fermentation equipment within a HEPA‐filter‐exhausted biological barrier. Within this barrier system, large‐scale processing that generates potentially hazaradous areosols (filtration, centrifugation of transformed cells or crystal slurries, and banding of viruses) should be isolated from other operations. Isolation of equipment is often required, with provision for both chemical and biological decontamination of process wastes. Failsafe fermentor over‐pressure sensors, parallel exhaust gas filtration, welded transfer lines, and modified sampling systems for elimination of aerosols can be installed on most fermentation equipment. Aerosol and spill containment by proper equipment design, coupled with appropriate personnel protective equipment and medical monitoring, make possible safe production of experimental growth factors and viruses from large‐scale culture of transformed mammalian cells and production of cytotoxic antitumor an

ISSN:0006-3592    

DOI:10.1002/bit.260260808

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

年代:1984

数据来源: WILEY

摘要:

AbstractIn many cases of fermentation processes, it is difficult to measure all of the state variables needed to indicate the culture state and to predict state changes. We propose the use of time‐series data of measurable state variables instead of unmeasurable to describe the fermenatation process. We also employ a discrimination method of independent variables of regression analysis using statistical measures, PSS and AIC. These statistical procedure were applied to fed batch culture for yeast production under aerobic conditions, and the effectiveness was ascertained experimentall

ISSN:0006-3592    

DOI:10.1002/bit.260260809

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

年代:1984

数据来源: WILEY

摘要:

AbstractA computer model is described which models an asynchronous population ofE. coliby using a large, but finite number of representative single cells. Asynchrony generation and maintenance occurs at the single cell level by modulating the activity of an enzyme responsible for septum formation. Such modulation introduces cycle time imprecision and does not require the introduction of any new parameters into the single‐cell model. Based on comparisons to experiment, reasonable predictions are possible for changes of cellular dry weight during exponential growth and turbidostat washout, and overall chemostat cell yields and changes in cell number, glucose concentration, and cell size distribution for a chemostat subject to a step change in dilution rate. Additionally, a correlation between cell RNA content and size is predicted as is an inertial effect when chemostat residence time is decreased under conditions of initially high glucose concentrations. Limitations imposed by the model's finite nature and their solutions are discusse

ISSN:0006-3592    

DOI:10.1002/bit.260260810

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe effects of pretreatment process variables [straw concentration between 20 and 90 kg volatile solids (VS)/m3, temperature between 30 and 85°C, and alkaline dosage between 0 and 80 g NaOH/kg VS] on acidogenesis and methanogenesis were investigated. Rates of acidogenesis and methanogenesis were determined using firstorder kinetics, and ultimate acid and methane yields were measured. The acid yield was not affected by pretreatment concentration or temperature, but increased as alkaline dosage increased. The acidogenesis rate was not affected by pretreatment temperature or alkaline dosage, but decreased as the substrate concentration increased. This decrease in the acidogenesis rate was attributed to a decrease in the inoculum: substrate ratio as the substrate concentration increased. The methane yield and methanogenesis rate were not affected by pretreatment substrate concentration or temperature, and both increased with alkaline dosage up to about 40 g NaOH/kg VS, then remained relatively constant above 40 g NaOH/kg VS

ISSN:0006-3592    

DOI:10.1002/bit.260260811

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

年代:1984

数据来源: WILEY