摘要:

AbstractKinetic studies on the parameters influencing the potential industrial application of an immobilized two‐enzyme system of β‐amylase and pullulanase for conversion of starch to a product with high maltose content, have been performed. The apparent Michaelis constant, the apparent product inhibitor constant, and the activation energy have been determined for the immobilized preparation and compared to the values for the corresponding soluble enzyme system. The catalytic activity of the immobilized enzymes was studied in a plug‐flow reactor and a continuous feed stirred tank reactor. Mathematical models for these reactors have been formulated and adapted to fit the experimental data. Comparisons of the reactor efficiencies were made and the conditions were found to be such as to favor the plug‐flow reactor. Results on operational stability tests at different temperatures and substrate concentrations a

ISSN:0006-3592    

DOI:10.1002/bit.260161202

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe microbial cells ofPseudomonas putidaATCC 4359 were immobilized by entrapment in a polyacrylamide gel lattice. Enzymatic properties ofL‐arginine deiminase of the immobilizedP. putidacells were investigated and compared with those of the intact cells. The permeability of substrate or product through the cell wall und the heat stability of the enzyme were increased by immobilization of the cells. No difference was observed between pH activity curves of the intact and immobilized cells. The optimal temperature for the formation ofL‐citrulline was 37°C for the intact cells and 55° C for the immobilized cells.When an aqueous solution of 0.5ML‐arginine hydrochloride (pH 6.0) was passed through a column packed with the immobilized cells at a flow rate ofSV= 0.26 at 37°C,L‐arginine was completely converted toL‐citrulline. The enzyme activity of the column was stable and the continuous production ofL‐citrulline could be carried out at 37°C for the month by using the immobilized cell column. From the effluent of the column,L‐citrulline was easily obtaine

ISSN:0006-3592    

DOI:10.1002/bit.260161203

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

年代:1974

数据来源: WILEY

摘要:

AbstractSeveral microorganisms having higherL‐histidine ammonia‐lyase activity were immobilized into polyacrylamide gel lattice. The yield of enzyme activity by immobilization was highest inAchromobacter liquidumIAM 1667. AsA. liquidumhas urocanase activity, the cells were heat‐treated at 70°C for 30 min to inactivate the urocanase.Enzymatic properties of the immobilizedA. liquidumcells were investigated and compared with those of the intact cells. No difference was observed between the pH activity curve and optimal temperature for the intact and immobilized cells. The permeability of substrate or product through the cell wall was increased by immobilization of the cells.When an aqueous solution of 0.25ML‐histidine (pH 9.0) containing 1mMMg2+was passed through a column packed with the immobilizedA. liquidumcells at a flow rate ofSV= 0.06 at 37°C,L‐histidine was completely converted to urocanic acid. TheL‐histidine ammonia‐lyase activity of the immobilized cell column was stable over 40 days at 37°C. From the effluent of the immobilized cell column, Urocanic acid was easily obtained

ISSN:0006-3592    

DOI:10.1002/bit.260161204

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

年代:1974

数据来源: WILEY

摘要:

AbstractContinuous fermentation of grape juice was studied in three basic kinds of nonmechanically stirred fermentors, classified according to the direction in which flow is applied against settling: upward‐flow, slant‐flow, and horizontal‐flow.Fermentation kinetics were found to be zero‐order, thus rate was directly proportional to cell density.Completeness of fermentation depends upon yeast characteristics (growth rate flocculation), fermentor geometry (settling depth, flow path length), and upon flow velocity.Fermentor analysis demonstrated that to achieve complete fermentation in the minimum juice holding time, efficient cell retention as well as rapid yeast growth and fermentation rates are required. Fermentor design and operation are discussed in the light of this a

ISSN:0006-3592    

DOI:10.1002/bit.260161205

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe β‐galactosidase fromEscherichia coliATTCC‐26 was partially purified and characterized. It was found to be comparable to galactosidases from otherE. colistrains in stability, pH and temperature maxima, and activity requirements, but it had a more favorable ratio of activity toward lactose versus synthetic substrates. The galactosidase was immobilized on porous glass beads by three covalent bonding methods. Kinetic data for the free and bound enzymes were determined using natural and synthetic substrates. Activity characteristics of the free and immobilized enzymes were comparable, however, the bound forms were less stable to

ISSN:0006-3592    

DOI:10.1002/bit.260161206

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

年代:1974

数据来源: WILEY

摘要:

AbstractAutomated sampling device was designed to permit determination of rates of biological transport of metabolites into cells. The substrate was automatically introduced into a stirred cell suspension at 37°C. The first sample was automatically taken after a mixing interval of 1 sec and nine subsequent samples were taken at programmable intervals (1 to 100 sec). The samples were forced by pressure differential (vacuum) through 0.4 μ pore size membranes and approximately 50 μl were collected in disposable cups. The duration of the sampling interval was controllable down to 0.1 sec. The samples preserved records of the substrate concentrations in solution at the time of filtration. With the use of suitable radioactive labeled isotopes, the changes in substrate concentrations may be conveniently measured by liquid scintillation spectrometry, but other analytical procedures of suitable sensitivity may be used. Initial and steady‐state transport rates of succinate and glucose inEscherichia coliwere obtained using the de

ISSN:0006-3592    

DOI:10.1002/bit.260161207

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

年代:1974

数据来源: WILEY

摘要:

AbstractImmobilized beef liver catalase has been used in a flow reactor to decompose hydrogen peroxide; at the same time the catalase is inactivated by its substrate. A model has been developed which predicts this rate of decomposition of peroxide and inactivation of catalase. First order dependence on peroxide concentration is assumed. The model was verified by experiment for a range of operating conditions and then used to predict the effects of a change in operating variables.

ISSN:0006-3592    

DOI:10.1002/bit.260161208

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

年代:1974

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260161209

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

年代:1974

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260161210

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

年代:1974

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260161201

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

年代:1974

数据来源: WILEY