摘要:

AbstractThe gyrogen with tubes has been the object of repeated trials carried out over a period of some years. The aim of these trials was essentially to multiply BHK cells in monolayer and to reproduce the FMD virus in one operation. At the laboratory stage, the gyrogen represented three roller flasks; at the pilot stage, 100 roller flasks; and at the industrial stage, 500 flasks. Culturing cells on a glass support, is not in itself new, but the difficulty appeared when replicating the virus in order to obtain the high parameters necessary for vaccine production. Everything was accomplished so that finally the cell culture and viral multiplication could be carried outin situin the same apparatus.

ISSN:0006-3592    

DOI:10.1002/bit.260220302

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe partition ofn‐hexadecane in the spent growth medium ofAcinetobactersp. HOI‐N was determined by measuring the increase in the relative aqueous solubility of3H‐hexadecane as compared to controls. The amount of hexadecane partitioned was proportional to the protein concentration. The specific solubility of hexadecane (nmol/mg protein) was analyzed by least‐squares fitting yielding an average slope of 0.6 with a standard deviation of 0.3, indicating either nonequilibrium of hexadecane or physical aggregation of protein. The amount of hexadecane partitioned was concentration dependent yielding optically clear microemulsions at hexadecane concentrations of less than 1.4mMand macroemulsions at hexadecane concentrations of 1.4mMor greater. Preliminary results indicated that hexadecane and partitioned by a lipoprotein

ISSN:0006-3592    

DOI:10.1002/bit.260220303

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe effect of temperature and pH on kinetic behavior of α‐galactosidase ofMortierella vinaceawas investigated on the hydrolysis ofp‐nitrophenyl‐α‐D‐galactopyranoside (PNPG). A very unusual kinetic behavior was observed for the soluble α‐galactosidase i.e., substrate inhibition diminished gradually with increasing temperature or near the neutral pH range, and the kinetics approached the ordinary Michaelis‐Menten (MM) type. On the other hand, with decreasing temperature or in acidic pH range, substrate inhibition was accelerated. Therefore, Arrhenius plots based on the initial reaction rate did not give straight lines. Furthermore, the slope in the Arrhenius plot changed with substrate concentration, which would make the determination of a characteristic value using conventional methods meaningless. However, the Arrhenius plots of individual kinetic parameters in the rate equation resulted in straight lines in the temperature range 15 to 50°C. From this, the drastic change in kinetic behavior could be explained in connection with the temperature and pH dependence of kinetic parameters in the model. For mold pellets (whole‐cell enzyme), however, the influence of temperature and pH was less apparent than that of soluble enzyme because of the limitation in intraparticle diffusion. By using the rate equation that was determined for soluble enzyme and the theoretically derived effectiveness factor, the overall reaction rate for mold pellets at various temperature and pH could be predi

ISSN:0006-3592    

DOI:10.1002/bit.260220304

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe hemicellulose fraction of ryegrass straw was extracted with NaOH and used for the production of glucose isomerase byStreptomyces flavogriseus. The level of hemicellulose extracted increased proportionately with increasing NaOH concentration up to about 4%, then the rate of increase slowed down. Hemicellulose extraction was facilitated by the combined application of heat and NaOH. Approximately 15% hemicellulose (12% as pentosan) could be obtained by treating straw with 4% NaOH for either 3 hr at 90°C or 24 hr at room temperature. The highest level (3.04 units/ml culture) of intracellular glucose isomerase was obtained when the organism was grown at 30°C for two days on 2% straw hemicellulose. The organism also produced a high yield of glucose isomerase on xylose or xylan. The NaOH‐treated straw residue, after removal of hemicellulose, had approximately 75% higher digestibility and 20% higher feed efficiency for weanling meadow voles than untreated straw. Thus, the residue could be used as animal feed. A process for the production of glucose isomerase and animal feed from ryegrass straw was also propo

ISSN:0006-3592    

DOI:10.1002/bit.260220305

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

年代:1980

数据来源: WILEY

摘要:

AbstractRaffinose was converted enzymatically in a hollow‐fiber reactor to melibiose, sucrose, galactose, glucose and fructose. The enzymes were a crude extract of α‐galactosidase and invertase produced byAspergillus awamoriNRRL 4869 on a solid substrate, Wheat bran. With a concentration of raffinose,C0, entering the reactor at a flow rateQ, and withCbeing the concentration of raffinose exiting the reactor, the conversion (C/C0), was studied as a function ofQat two level ofC0. The data could be fairly well fitted using the analysis of Waterland et al. even though a mixed crude enzyme system was being investigated. It was found empirically that In (C/C0) was linear inQ−1, with the absolute value of the slope decreasing with increasingC0. The linearity of such plots were predicted by Lewis and Middleman from Waterland et al. for a single enzyme system obeying first‐order kinetics, the slope being independent ofC0. Although the assumptions involved in this approximate analytical solution are not valid, the observed linearity of the In (C/C0) vs.Q−1plots is excellent and should prove useful in reactor design cons

ISSN:0006-3592    

DOI:10.1002/bit.260220306

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

年代:1980

数据来源: WILEY

摘要:

AbstractIn this investigation, the activation energies of the hydrolysis ofN‐(α)‐benzol‐L‐arginine ethyl ester (BAEE) and casein have been determined using trypsin immobilized on molecular sieve type 4A. There is a complete absence of intraparticle diffusion in the system, and the temperature dependence of the reaction has been studied only under external diffusional limitation. While the hydrolysis of BAEE by bound trypsin in found to be controlled by external diffusion, that of casein is kinetically co

ISSN:0006-3592    

DOI:10.1002/bit.260220307

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe progesterone 11α‐hydroxylase ofRhizopus nigricansATCC 6227b is an inducible enzyme system that is primarily induced by its substrate progesterone. Maximum induction was found at a progesterone concentration of 0.5 g/liter or above. Oxygen is the other substrate for the hydroxylation and this was found to have a major effect on the amounts of hydroxylase synthesized. Optimum induction of the hydroxylase in a fermentation with a 3.1 m/sec impeller tip speed was found to occur at a dissolved oxygen tension (DOT) of 10% of air saturation. The agitation rate also effects the amount of hydroxylase synthesized with an apparent maximum at 3.1 m/sec impeller tip speed. The DOT for a maximum hydroxylation rate was much higher than for enzyme synthesis so that it was preferable to increase the DOT after induction was complet

ISSN:0006-3592    

DOI:10.1002/bit.260220308

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

年代:1980

数据来源: WILEY

摘要:

AbstractIn a system where yeast cells grow onn‐alkanes dissolved in oil drops suspended in water, the dispersed oil phase will, in most cases, be fully segregated. This means that each drop has its own history that depends on its degree of saturation with yeast cells. This degree of saturation with yeast cells is determined by a stochastic process depending on adsorption, desorption, and cell production. Although many authors mention segregation as a phenomenon likely to occur, so far this segregation has hardly been taken into account. In this paper the interaction of the population of completely segregated oil drops with the population of yeast cells, which results in growth, is described. The consequences of the model are elucidated by the discussion of some extreme cases. The batch fermentation of hydrocarbons by yeast cell is simulated by means of a Monte Carlo procedure. Adsorption, desorption, and production of yeast cells are considered as chance processes. The history of all individual drops is recorder. The influence of the chance of desorption appears to be much larger than that of the chance of adsorption (at the investigated range). Also the size of the inoculum at the start of the process appears to have a strong influence on the course of fermentatio

ISSN:0006-3592    

DOI:10.1002/bit.260220309

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

年代:1980

数据来源: WILEY

摘要:

AbstractIn the stochastic as well as in other models that describe the growth of yeast on liquid hydrocarbons, the adsorption and desorption of cells to drops influence to a very great extent the growth rate of the cells. In this paper a method is presented and equipment is described by which it was possible to measure the cell‐drop interaction directly. While analyzing the results of these measurements it was found that the adsorption and desorption of cells are rather complicated processes. The size distribution of the oil drops is one of the parameters that has to be taken into account. The analysis of the results yields a fairly accurate value for the initial adsorption rate. Departing from a somewhat speculative description of the influence of drop size distribution on the adsorption rate, the order of magnitude of the desorption rate constant could be calculate

ISSN:0006-3592    

DOI:10.1002/bit.260220310

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

年代:1980

数据来源: WILEY

摘要:

AbstractIn this paper the results of the Monte Carlo simulations as described in an earlier paper are compared with those of batch experiments. A number of batch experiments were carried out at a low inoculation rate so that only a fraction of the oil drops were inoculated. Under these conditions the effect of the segregation of the oil phase is more clearly demonstrated. Special attention is paid to the preparation of actively growing yeast cells with which the cultures is inoculated. Also a method is developed to estimate the amount of actively growing cells with which the culture is inoculated. The other parameters necessary for the Monte Carlo simulation are measured in separate experiments: the maximum growth rate of the cells, oil drop size, and the drop parameters. Finally the growth curves (measured in the batch experiments) are compared with those calculated with the Monte Carlo procedure. A good agreement is found.

ISSN:0006-3592    

DOI:10.1002/bit.260220311

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

年代:1980

数据来源: WILEY