摘要:

AbstractThe validity of regarding the liquid phase in vigorously agitated sparged fermenters during the cultivation of single‐celled aerobic microorganisms as essentially homogeneous is examined. Droplet formation from bursting bubbles and physical effects of the spray environment on single‐celled microorganisms are discussed. The implications of droplet removal from the head space of fermenters by collision with and drainage down the walls are considered, particularly factors concerned with wall growth above the liquid level in ferment

ISSN:0006-3592    

DOI:10.1002/bit.260140102

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

年代:1972

数据来源: WILEY

摘要:

AbstractA discrete optimally sensitive controller is developed which yields steady‐state feedback control of a three‐stage biochemical reactor system in spite of system parameter variations. A feedback law is implemented that estimates those variations which cause the output states to deviate from nominal, and adjusts the control policy in light of these variati

ISSN:0006-3592    

DOI:10.1002/bit.260140103

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

年代:1972

数据来源: WILEY

摘要:

AbstractSingle‐stage continuous fermentations to produce xanthan gum have been run at dilution rates (D) from 0.023 to 0.196 hr−1. Xanthan production rate (XPR) was a function ofD. XPR increased from 0.34 g/hr/kg atD= 0.023 hr−1to the maximum 0.84 g/hr/kg atD= ca. 0.15 hr−1. AtD>0.15 hr−1XPR decreased and at the highestDstudied (0.196 hr−1) was 0.69 g/hr/kg. Yield of xanthan from glucose consumed was 81–89%. Steady states ended between 6.5 and 8.7 turnovers when a variant st

ISSN:0006-3592    

DOI:10.1002/bit.260140104

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

年代:1972

数据来源: WILEY

摘要:

AbstractThe release constant,k, of brewers yeast sonicated at powers up to 200 W at 20 kHz has been shown to be independent of cell concentration up to values of 60 g made up to 100 ml. It is inversely proportional to the volume of the treatment vessel in the range 75 to 450 ml, and almost proportional to the input acoustic power from 60 to 195 acoustic watts. A flow system is described and a relationship linking protein release, flow rate, and the protein release constant, determined from batch experiments, is derived. Good agreement between the theoretical prediction of protein release and experimental results with the flow system was obtained.

ISSN:0006-3592    

DOI:10.1002/bit.260140105

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

年代:1972

数据来源: WILEY

摘要:

AbstractIn this work, a radiometric method is used for the determination of the oil drop size distribution in agitated hydrocarbon–water systems. The influence of the counter position, the oil concentration, and the rotation speed of impeller were studied. An experimental parameter is proposed for the definition of the drop size distribution. It was observed that an unsymmetrical distribution represents the drop size distribution better than the normal distribution la

ISSN:0006-3592    

DOI:10.1002/bit.260140106

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

年代:1972

数据来源: WILEY

摘要:

AbstractA kinetic model has been presented to explain the growth of microorganism on solid hydrocarbons. The model is based on the assumption that metabolite produced by the growing cells helps the dissolution of the solid substrate in the aqueous medium. The linear behavior of the growth curve predicted by the model is verified experimentally.

ISSN:0006-3592    

DOI:10.1002/bit.260140107

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

年代:1972

数据来源: WILEY

摘要:

AbstractThe bacteriumAcetobacter suboyxdansand the yeastSaccharomyces carlsbergensishave been grown together on a synthetic medium in a chemostat. Mannitol, the only carbon source fed to the fermenter, is oxidized by the bacteria to fructose. The yeast, which cannot attack mannitol, breaks down the fructose nearly completely. Eight steady states and five transitory periods after changes in flow rate have been analyzed to study the kinetics of the mixed culture. Separate cell concentrations were determined by a modified Coulter counter apparatus. Both sugars were monitored. Both bacteria and yeast may be modeled using Monod's equation, the latter with some deviations. The yeast is unable to grow beyond the washout point of the bacteria, even though its maximum growth rate is much higher. The yield of both organisms decreases with increasing dilution rate, as does their average cell size. After step changes in dilution rate, repeated oscillations of both sugar and cell concentrations usually occur before steady‐state conditions are reattained. They are generally in phase, with no definite sign of a lag. Oscillations of yeast and fructose concentrations are more pronounced. Periods average about 6 hr and are not correlated with fermentation conditions or equipment variables. Repeated oscillations are not found after step‐downs in pure cultures ofA. suboxydans, leading to the conclusion that the instability in mixed cultures may be caused by a feedback mechanism from the yeast to the bacte

ISSN:0006-3592    

DOI:10.1002/bit.260140108

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

年代:1972

数据来源: WILEY

摘要:

AbstractIn experiments with one freshwater (Chlorella pyrenoidosa) and three marine organisms (Phaeodactylum tricornutum, Cyclotella nana, andChaetoceros galvestonensis), mecury was more toxic than the other metals tested (silver, cadmium, lead, and copper); and its toxicity is comparatively irreversible. Growth was monitored by changes in fluorescence of the cultures over a 3‐day test period. The toxicity of the mercury varied inversely with the concentrations of nutrients present. Preliminary experiments indicate that mercury in the form of mercuric chloride is more than as dimethylmercur

ISSN:0006-3592    

DOI:10.1002/bit.260140109

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

年代:1972

数据来源: WILEY

摘要:

AbstractWe developed an efficient and simple method for RNase extraction fromCandida lipolyticacells which consists of predrying the cells with solvents and incubating them for 8 to 15 hr at 37 to 45°C in a slightly acid buffer which contains EDTA or salts. This method is called Solvent Dehydration Buffer Extraction (SDBE) procedure. Predrying with acetone or ethanol, or by lyophilization, followed by washing with acetone or ethylacetate gives the most efficient RNase extraction. The yield and specific activity obtained by this extraction procedure are higher than by any other method examined. An apparent 1.5‐ to 2.0‐fold activation of RNase occurred during the SDBE process. Activation of RNase in homogenates obtained by grinding fresh cells is also observed with EDTA or acetate buffer. The SDBE procedure works efficiently regardless of growth phase forCandida lipolytica, and works also with otherCandidaye

ISSN:0006-3592    

DOI:10.1002/bit.260140110

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

年代:1972

数据来源: WILEY

摘要:

AbstractPseudomonas fluorescens(ATCC 11150) was grown in batch and continuous culture in minimal media with sodium maleate as growth‐limiting sole organic carbon source. Growth was followed by turbidity and dry weight measurements. Gross composition of washed cells (relative amounts of protein, lipid, RNA, and DNA) and the distribution of amino acids in protein hydrolyses of the cells were determined for cells grown in continuous culture at various dilution rates. Extracellular concentrations of the original carbon source and a number of metabolites were monitored by a total carbon analysis, ion exchange chromatography, and ultraviolet‐visible scans of cell‐free supernatants and chromatographic fractions, thereof.Substrate inhibition by maleate was a major factor in the growth kinetics of both batch and continuous cultures. Excessive maleate concentration caused instability in continuous cultures. By appropriate operation, much higher specific growth rates (0.305/hr) could ultimately be achieved in continuous culture compared to batch culture (0.174/hr). Adaptation was responsible for only part of the differences between batch and continuous cultures; the differing distribution of metabolites were also major fa

ISSN:0006-3592    

DOI:10.1002/bit.260140111

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

年代:1972

数据来源: WILEY