摘要:

AbstractTwo simultaneous fermentations were performed at 26°C with simultaneous inocula usingClostridium saccharoperbutylacetonicum.Fermentation 1 prevented the gas formed by the biomass from escaping the fermentor while 2 allowed the gas formed to escape. Fermentor 1 provided for the production of butanol, acetone, and ethanol, while when the H2formed was allowed to escape with fermentor 2, neither butanol nor acetone were produced. Ethanol was also formed in both fermentors and began along with the initial growth of biomass and continued until the fermentations were complete. Butanol and acetone production began after biomass growth had reached a maximum and began to subside. The butanol‐acetone‐ethanol millimolar yields and ratios were 38:1:14 respectively. The fermentor 2 results show that a yield of 2.1 L H2, 93 or 370 mmol H2/mol glucose, was formed only during the growing stage of growth; neither butanol nor acetone were produced; ethanol was formed throughout the fermentation, reaching a yield of 15.2 mmolar. It appears that hydrogen gas is required for butanol production during the resting stage of gr

ISSN:0006-3592    

DOI:10.1002/bit.260280302

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

年代:1986

数据来源: WILEY

摘要:

AbstractPlasmid as an extrachromosomal genetic element is an important vehicle to support the recombinant DNA technology. A picture on plasmid number per cell as a basis of expecting the gene dosage effect is worthy of drawing from the application to practice. The purpose of this communication is to present an overall and stochastic picture on the dynamics of plasmid number per cell in relation to the specific growth rate of the host cell.

ISSN:0006-3592    

DOI:10.1002/bit.260280303

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

年代:1986

数据来源: WILEY

摘要:

AbstractUsing a continuum approach and observing conservation principles, an analytical mathematical model of microbial interaction in biofilms was developed. The model predicts changes in biofilm thickness and describes the dynamics and spatial distribution of microbial species and substrates in the film. It allows for biomass detachment due to shear stress and sloughing, external mass transfer limitations, as well as variations in substrate concentrations in the bulk liquid. A computer implementation of the model is provided using an example of heterotrophicautotrophic competition to illustrate how the observed phenomena can be numerically reproduced and indicating how they might affect overall biofilm performance.

ISSN:0006-3592    

DOI:10.1002/bit.260280304

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

年代:1986

数据来源: WILEY

摘要:

AbstractA radial flow hollow fiber bioreactor has been developed that maximizes the utilization of fiber surface for cell growth while eliminating nutrient and metabolic gradients inherent in conventional hollow fiber cartridges. The reactor consists of a central flow distributor tube surrounded by an annular bed of hollow fibers. The central flow distributor tube ensures an axially uniform radial convective flow of nutrients across the fiber bed. Cells attach and proliferate on the outer surface of the fibers. The fibers are pretreated with polylysine to facilitate cell attachment and long‐term maintenance of tissuelike densities of cell mass. A mixture of air and CO2is fed through the tube side of the hollow fibers, ensuring direct oxygenation of the cells and maintenance of pH. Spent medium diffuses across the cell layer into the tube side of the fibers and is convected away along with the spent gas stream. The bioreactor was run as a recycle reactor to permit maximum utilization of nutrient medium. A bioreactor with a membrane surface area of 1150 cm2was developed and H1 cells were grown to a density of 7.3 × 106cells/c

ISSN:0006-3592    

DOI:10.1002/bit.260280305

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

年代:1986

数据来源: WILEY

摘要:

AbstractNocardia corallinaB276 cells were immobilized by emulsification with liquid paraffin and an antifoam agent at room temperature. The immobilized cells were studied for their ability to carry out the formation of propylene oxide from propylene and oxygen. The evaluations were done with the cells in a bubble‐type reactor with a continuous gas feed of 5% propylene and 11.6–95% oxygen, with the balance nitrogen. By using liquid paraffin and antifoam, both the epoxidation activity and the stability were improved, especially for the P‐1‐200 strain, over that for nonimmobilized cells. TheN. corallinacells showed an apparent preference for a hydrophobic, as compared to a hydrophilic, environment. The propylene‐oxide‐forming activity of the immobilized cells was higher at 40 than at 30°C reactor temperature and with 20% (versus 95%) oxygen in the feed. The stability was markedly better at 30°C and with 20% oxygen. High gas flowrates gave increased apparent activity probably because of less resistance to substrate mass transfer. The effects of pH were minor. The role of glucose as the energy source for regeneration of cofactors for the monooxygenase system also

ISSN:0006-3592    

DOI:10.1002/bit.260280306

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

年代:1986

数据来源: WILEY

摘要:

AbstractCrystalline insulin was obtained from the pancreas by the method of ultrasound extraction. Extreme changes of pancreas structure were noticed, including rupture of the cells of pancreatic islands and decomposition of pancreatic tissue with the formation of micro‐and macro‐canals. These changes facilitate the migration of solvent inside the structure and washing out β cell content. Structural changes were maximal in the peripheral parts of the pancreas and in frozen pancreas treated by ultrasound. A rapid filming method recorded factors influencing the extraction process—the dispersing effect of ultrasound, the rapid destruction of pancreatic particles, and the swelling and intensive pulsation of small particles in the ultrasound field. Experimental, control, and standard insulin preparations were nearly identical in Physicochemical properties and ether quality characteristics: activity determined by a biological method and electrophoresis; homogeneity and purity determined by circle chromatography; fractions of insulin determined by starch gel electrophoresis; amino acid composition; solubility; and content of moisture, zinc, and ni

ISSN:0006-3592    

DOI:10.1002/bit.260280307

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

年代:1986

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260280308

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

年代:1986

数据来源: WILEY

摘要:

AbstractAnadaptive measuring systemof themain variables of biotechnical processesbased on thetheory of estimationis elaborated upon here. All stages of system synthesis are considered. It is shown that for an adaptive measuring system alla prioriinformation on modelling and measurement noise and process mathematical models must be used. The data ofdirectandindirect measurementsare used for estimating the main variables. The performance of the proposed measuring system was checked usingimitative modelling.

ISSN:0006-3592    

DOI:10.1002/bit.260280309

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

年代:1986

数据来源: WILEY

摘要:

AbstractTwo continuous stirred tanks reactors (CSTR) and four anaerobic fluidized bed reactors (AFBR) were used to study the treatment of a synthetic meat waste during single‐and two‐stage anaerobic treatment. Four configurations were investigated; a single‐stage CSTR and AFBR and the two‐stage systems CSTR–AFBR and AFBR–AFBR. Startup of the anaerobic reactors was achieved within 50 days by use of a regime that included stepped increases in influent COD, methanol substitution of the substrate, and addition of essential trace metals such as cobalt and nickel. Two‐stage reactors removed up to 85% of influent COD concentrations of 5000 mg/L, whereas the single‐stage AFBR and CSTR removed 76 and 9%, respectively. The proportion of methane in the effluent gases increased as the influent COD concentration was increased. Volumetric production of methane was greatest for the first stage of the AFBR–AFBR system. Solids retention times calculated for the AFBRs ranged from 7 to 12 days, sufficient to support methanogenesis. The AFBRs and two‐stage systems were more resistant to an influent pH shock from the operating value of pH 6.8 down to pH 3 than the CSTRs and single‐stage reactors. It was concluded that high‐rate anaerobic treatment systems were applicable to meat industry wastewaters and that two‐stage digestion produced

ISSN:0006-3592    

DOI:10.1002/bit.260280310

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe ligninolytic activities of four cellulolytic organisms were compared using straw. OnlyAspergillus japonicusandPolyporous versicolorappreciably degraded lignin withA. japonicusyielding the most protein. In solid culture, most protein was produced byP. versicolor, closely followed byA. japonicus.Pretreatment of the straw by hot water facilitated biodegradation and protein production. The nutritional value of the residual straw was also increased by some fungal cultures. The greatest amount of degradable polysaccharide in the straw was made available byA. japonicusin liquid media andPleurotus ostreatusin solid media.

ISSN:0006-3592    

DOI:10.1002/bit.260280311

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

年代:1986

数据来源: WILEY