摘要:

AbstractA consecutive, first‐order, irreversible, biochemical reaction,\documentclass{article}\pagestyle{empty}\begin{document}$ A{\textstyle{{k(\theta)} \over {{\rm Enzyme }1}}} \to B{\textstyle{{k(\theta)} \over {{\rm Enzyme 2}}}} \to C $\end{document}, taking place in a series ofNreactors with product recycle is considered. A discrete version of the maximum principle is used to derive general equations necessary for maximizing the production of (1) the final product,C, by choosing the temperature or the pH value in each reactor, and (2) the intermediate product,B, by choosing the reactor volume. A numerical computation for a series of three reactors with recycle is illustrated. The effects of varying the recycle rates on the optimal state and decision variables are also presente

ISSN:0006-3592    

DOI:10.1002/bit.260090202

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

年代:1967

数据来源: WILEY

摘要:

AbstractMathematical models for microbial growth in batch and continuous cultures are formulated. The models have been referred to as distributed models since the microbial population in a culture is looked upon as protoplasmic mass distributed uniformly throughout the culture. Growth is regarded as the increase in this mass by conversion of medium components into biological mass and metabolic products. Two sets of models have been presented. The first arise from introducing additional considerations into the model proposed by Monod to account for the stationary phase and the phase of decline in a batch culture. These have been referred to as unstructured, distributed models since they do not recognize any form of structure in the protoplasmic mass. The models in the second set are referred to as structured, distributed models. Structure is introduced by considering the protoplasmic mass to be composed of two groups of substances which interact with each other and with substances in the environment to produce growth. The structured models account for the dependence of growth on the past, history of the cells; thus they predict all growth phases observed in batch cultures, whereas the unstructured models do not predict a lag phase. The full implications of the models for continuous propagation, as determined by the method of stability analysis and transient calculations, are discussed. The models prediet a number of new results and should be confronted with experiments.

ISSN:0006-3592    

DOI:10.1002/bit.260090203

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

年代:1967

数据来源: WILEY

摘要:

AbstractSubmerged acetification experiments were performed to determine conditions necessary for the production of a satisfactory vinegar from waste pineapple juice using a pure culture inoculum. Vinegars containing up to 7%, by weight of acetic acid could be produced in less than 24 hr. with a conversion efficiency greater than 90% in both laboratory and pilot plant equipment. None of the bacterial nutrients added to the juice improved either the rate of production or the yield of acetic acid. Oxygen transfer during the process is discussed.

ISSN:0006-3592    

DOI:10.1002/bit.260090204

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

年代:1967

数据来源: WILEY

摘要:

AbstractAn experimental investigation is presented of the foam separation of six species of bacteria:Escherichia coli, Serratia marcescens, Proteus vulgaris, Pseudomonas fluorescens, Bacillus cereus, andBacillus subtilisvarniger. A cationic surfactant, ethylhexadeeyldimethylammonium bromide is used and results are evaluated in terms of total cell count, using a membrane filtration technique. From similar neutral distilled water suspensions of the pure cultures (approximately 107cells/ml.) and using the same operating conditions, ratios of cell concentrations in the residual suspensions to those in the initial suspensions range from 0.0013 forBacillus subtilisvarnigerto 0.25 forSerratia marcescens.The presence of bacteria, compared to pure surfactant solutions, produces lower collapsed foam volumes; the foam volumes have a strong influence on the separations achieved with the various species, with enrichment ratios ranging from 27 to 3088 and residual ratios ranging from 0.001 to 0.247.

ISSN:0006-3592    

DOI:10.1002/bit.260090205

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

年代:1967

数据来源: WILEY

摘要:

AbstractA strain ofKlebsiella aerogeneswas selected which gave marked diauxic growth in a batch system on a mixture of glucose and lactose in a simple salts medium; the diauxic lag was 15–20 hr. at 30°C. The growth of this organism on glucose and lactose was studied in a single‐stream two‐stage continuous‐stirred fermentor system over a wide range of flow rates. Glucose was metabolized instantaneously to give very low reactor concentrations at all flow rates, but the time lag before lactose was attacked, when present for the first time, was never less than 40 hr. at low feed rates, rising to 60 hr. at higher rates. The adaptation to lactose of cells in the first vessel lagged behind that in the second vessel but eventually both sugars were completely utilized in the first vessel except at very high dilution rates. At these feed rates, lactose utilization was not only prevented completely in the first vessel but also could be delayed almost indefinitely in the second vessel at the highest dilution rates; thus the lactose passed unchanged through both vessels. Once the enzymes required for lactose utilization had been induced, this ability to use lactose was retained, even in the absence of lactose, for very long periods of time under continuous conditions. Thus on presenting lactose for the second and subsequent occasions it was immediately metabolized. The significance of these results is d

ISSN:0006-3592    

DOI:10.1002/bit.260090206

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

年代:1967

数据来源: WILEY

摘要:

AbstractBatch growth characteristics of various organisms were determined on a number of pairs of sugars to find a stable system showing clear‐cut classical diauxie. The system selected for further study was a strain ofKlebsiella(Acrobacter)aerogenes, NCIB 8021 growing on a mixture of glucose and maltose in minimal salts medium at 30°C. This showed a specific growth rate (μ) of 1.19 ± 0.03 hr.−1on 0.01% (w/v) glucose, followed by a diauxie lag of 0.73 ± 0.04 hr and then further growth on 0.01% (w/v) maltose at μ = 0.60 ± 0.03 hr−1. This system was applied to a two‐stage continuous, stirred, aerated fermentor system, with working volumes of 1.85 and 2.77 liters, respectively, and growth was followed (mainly by optical density, referred to dry weights and viable counts) and also the concentrations of the sugars were measured. Except at the very highest flow rates, glucose was immediately and virtually completely consumed, but the utilization of maltose showed interesting variations: (a) At low feed rates between 0.09 and 0.4 vol./hr. exactly the same response was found with mixed sugars as with double concentration glucose, showing that the organism was able to metabolize maltose as well and as quickly as glucose. (b) At medium feed rates of 0.46 to 1.03 vol./hr. two deviations were observed, both of which increased as the dilution rate increased: the system showed a time lag on maltose before the cell population began to rise and the volume of medium used before the steady state was established was greater than predicted, (c) At fast feed rates, approaching “washout” condition of 1.055 to 1.135 vol./hr. the first culture vessel showed no reaction to a step change which included maltose, although, of course, with doubled glucose it responded immediately. The second vessel, however, quickly metabolized the overflow maltose, and showed a steady increase of cell population to the theoretical steady state. These results may have significance for industrial systems using complex comm

ISSN:0006-3592    

DOI:10.1002/bit.260090207

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

年代:1967

数据来源: WILEY

摘要:

Abstract(1) Samples of yeast which varied over an arbitrary 0–100% scale with respect, to cytochrome concentration were prepared. (2) The reflectance spectrum of each sample was scanned. (3) These reflectance spectra were analyzed numerically on a digital computer to determine the bandwidths and intensities as a function of cytochrome concentration. Band shapes using the profiles of Cauchy, Gauss, and Giovanlelli were used. The correlations may be used to estimate cytochrome concentrations with a standard deviation of about 3

ISSN:0006-3592    

DOI:10.1002/bit.260090208

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

年代:1967

数据来源: WILEY

摘要:

AbstractStudies are made of the behavior of liquid contents in a closed cylindrical vessel vibrated vertically along its axis. The situation is one which had been investigated by Rodgers and Hughes (1960) because of applications in microbiology and biochemistry. By use of motion pictures it was found that surface waves develop, sonic fog is produced, and air bubbles are formed at the onset of the motion. Bubbles then move downward until, under conditions of practical interest, air is divided equally between top and bottom of the vessel. Steady‐state vertical oscillation of the central liquid body then ensues, superposed on turbulent action of air–water mixtures at the top and bottom of the vessel. Reference is made to available theory for surface wave excitation, and bubble migration. A nonlinear differential equation is considered for the steady‐state oscill

ISSN:0006-3592    

DOI:10.1002/bit.260090209

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

年代:1967

数据来源: WILEY

摘要:

AbstractThe growth of Semliki Forest Virus in stirred culture vessels at volumes of 4 and 301. is described. Virus can be produced on a large scale in deep culture using industrial type vessels. Control of pH within close limits is important for maximum production of infective virus. With the parent, strain of SFV, virus yields were found to be influenced by an interference phenomenon which was apparently not due to interferon. Growth of a cloned strain of SFV obtained by serial selection of large plaques was not affected by this phenomenon. The cloned strain, when inoculated at a cell/virus input ratio of 1:1, gave maximum virus titers of 1010p.f.u./ml., indicating an average yield of 10,000 p.f.u/BHK cell.

ISSN:0006-3592    

DOI:10.1002/bit.260090210

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

年代:1967

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260090211

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

年代:1967

数据来源: WILEY