摘要:

AbstractA continuous‐flow, high throughput, turbine‐driven zonal centrifuge has been contained for use with biologically hazardous materials. The centrifuge and all ancillary equipment are enclosed in three sealed cabinets that are maintained at negative pressure, decontaminated with ethylene oxide, and provide cooling for the process fluids. Sample handling is semiautomated and remotely controlled for ease of operation and includes an automated decontamination system. The centrifuge subsystems can be decontaminated prior to an engineer servicing the machine, and apparatus is provided for absolute filtration of the centrifuge turbine exha

ISSN:0006-3592    

DOI:10.1002/bit.260230102

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

年代:1981

数据来源: WILEY

摘要:

AbstractPilot‐scale investigations into the application of ultrafiltration (UF) for concentrating bovine blood or a mixture of bovine and ovine blood are described. Tests were carried out in an Iopor 6CL UF system and a Romicon (hollow fiber) UF system. Optimal operating conditions for these two system were evaluated. Starting from a 18–20% TS lood concentration final concentrations of 28–30% TS were achieved. The lopor system was found to be more suited for processing blood and the average flux values obtained indicated UF to be a more economical process for concentrating blood than vacuum evapor

ISSN:0006-3592    

DOI:10.1002/bit.260230103

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

年代:1981

数据来源: WILEY

摘要:

AbstractStreptomyces fradiaewas immobilized in polyacrylamide gel prepared from 5% total acrylamide (90% acrylamide and 10%N,N′‐methylenebisacrylamide). Production of protease by the immobilized mycelia was attempted in a batch system. A dilute medium containing 0.5% starch, 0.5% meat extract, and 0.05% yeast extract was employed. The reusability of the immobilized and washed mycelia was examined. The activity of protease production by washed mycelia was rapidly decreased with increasing use cycles. The activity of the immobilized mycelia increased gradually, and reached a maximum after ten use cycles. Then, the activity gradually decreased with increasing reaction cycles. This might be caused by destruction of the gels. On the other hand, the sterilization of the surface of the immobilized mycelia was effective for elongation of the lifetime. As a result, the half‐life of protease production by the sterilized immobilized mycelia was about 30 days. The rate of protease production by immobilized mycelia was 12,000 U/ml/hr. This value was four times higher than that by submerged cu

ISSN:0006-3592    

DOI:10.1002/bit.260230104

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

年代:1981

数据来源: WILEY

摘要:

AbstractAn operational scheme for using immobilized enzymes in packed‐bed reactors that permits operation at a constant throughput rate and constant product quality is described. The scheme used columns operated in series with continuous enzyme addition to compensate for enzyme decay. A mathematical technique was developed to determine the enzyme addition rate, enzyme usage, and enzyme volume in the column system. Operation of columns in series is compared to operation where the flow rate is decreased to compensate for a loss of enzyme activity for both zero‐and first‐order decay. The analyses indicated that columns in series resulted in better enzyme utilization but larger reactor volumes than parallel reactors with decreasing flow

ISSN:0006-3592    

DOI:10.1002/bit.260230105

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

年代:1981

数据来源: WILEY

摘要:

AbstractCorn stover was fermented by anaerobic acidogenic bacteria to produce volatile (C2–C6) organic acids. Mild pretreatment with dilute alkali solutions produced a two‐fold increase in fermentability. A mixture of lime and sodium carbonate was found to be a better pretreatment agent than sodium hydroxide. Methane generation was inhibited by low temperature (⩽ 25°C) and high solids [≥ 2.5% (w/v)] fermentation. Volatile acid yields of 0.5–0.55 g acetic acid equiv/g dry ash‐free (DAF) stover could be obtained in batch fermentations. Several extractants and extraction solvents for organic acids were found to be nontoxic to acidogenic fermentation. The data show that acidogenic fermentation can produce useful volatile fatty acids in high yields from a complex lignocellulosic feedstock. These fermentations are nonsterile, need no stirring, and are easy to run. Moreover, cellulose, pentosans, and other carbohydrates are directly utilized by acidogenic bacteria. Hence, acidogenic fermentation could be useful in converting biomass to chemical feedsto

ISSN:0006-3592    

DOI:10.1002/bit.260230106

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

年代:1981

数据来源: WILEY

摘要:

AbstractA flat‐bed hollow‐fiber cell culture system has been developed which maximizes the utilization of the large fiber surface while diminishing significantly the problems inherent in a cartridge‐type reactor. The reactor core consists of a shallow bed of hollow fibers sandwiched between two stainless‐steel microporous filter plates through which the media flow is directed normal to the plane of the fiber bed. Reactors with both 930 and 9300 cm2of fiber surface have been successfully constructed and operated. A variety of cells has been grown in these reactors including SV3T3 cells, baby hamster kidney cells, Vero cells, and rhesus money kidney cells, and cell products such as plasminogen activator and migration inhibition factor (MIF) were produced. This system offers an excellent prototype for scaleup

ISSN:0006-3592    

DOI:10.1002/bit.260230107

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe conditions for culture storage, inoculum preparation, and growth of aCytophagaspecies, constitutive with respect to yeast‐lytic enzymes, have been established in shake‐flask studies and in 5 liter fermentor experiments. A low cost medium was adopted for 900 liter‐scale fermentation and gave an enzyme activity in the fermentation broth somewhat greater than the comparable laboratory‐sc

ISSN:0006-3592    

DOI:10.1002/bit.260230108

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

年代:1981

数据来源: WILEY

摘要:

AbstractA modal has been described for the influence of growth rate and shear stresses in the fermentor upon the morphology of filamentous molds. The main concept of this model is the dynamic equilibrium between growth and breakup of the hyphae. The latter has been approached according to well‐known engineering theories for dispersion of physical systems. Experiments to verify the model with a strain ofPenicillium chrysogenumin batch and continuous culture revealed that the length of the mycelial particles increased with increasing growth rate and decreased with increasing power input her unit mass in the fermentor. Although this was qualitatively in agreement with the presented model, quantitatively the model had to be rejected. Variation of the tensile strength of the hyphae with age and culturing conditions could have been one of the causes of disagreement. Oxygen tension, varied independently from stirrer speed, in the range of 12–300 mm Hg was shown to have no influence upon the morphology. With respect to the question of possibly using high‐energy inputs in industrial mold fermentation in order to decrease hyphal length and suspension viscosity, it was concluded that this is of little practical value. A substantial decrease in hyphal length requires an enormous increase in energy

ISSN:0006-3592    

DOI:10.1002/bit.260230109

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

年代:1981

数据来源: WILEY

摘要:

AbstractA semiautomatic method for the quantitative representation of mold morphology is described.

ISSN:0006-3592    

DOI:10.1002/bit.260230110

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

年代:1981

数据来源: WILEY

摘要:

AbstractA range of cellulosic raw materials in the form of agricultural crop residue was analyzed for chemical composition and assessed for potential yields of sugars through chemical pretreatment and enzymatic hydrolysis of these materials. Corn stover was used as a representative raw material for a preliminary process design and economic assessment of the production of sugars and ethanol. With the process as presently developed, 24 gal ethanol can be obtained per ton of corn stover at a processing cost of about $1.80/gal exclusive of by‐product credits. The analysis shows the cost of ethanol to be highly dependent upon: (1) the cost of the biomass, (2) the extent of conversion to glucose, (3) enzyme recovery and production cost, and (4) potential utilization of xylose. Significant cost reduction appears possible through further research in these direction

ISSN:0006-3592    

DOI:10.1002/bit.260230111

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

年代:1981

数据来源: WILEY