ABSTRACT
High-dispersed silicon dioxide--aerosil A-300 has been studied for its effect on the growth of yeast Saccharomyces cerevisiae. It is shown that at heterophase cultivation of these microorganisms under periodical conditions introduction of aerosil A-300 induces a decrease of the lag phase duration and an increase of the maximum specific growth rate and economic coefficient of the carbon substrate utilization. This high-dispersed material has exerted the similar effect under the conditions of chemostatic cultivation. Optimal parameters of this process are determined.
Subject(s)
Saccharomyces cerevisiae/drug effects , Silicon Dioxide/pharmacology , Culture Media , Dose-Response Relationship, Drug , Saccharomyces cerevisiae/growth & developmentABSTRACT
Optimal conditions of the glucose isomerase fixation in a cell are determined by thermal treatment of Str. robeus S-606 biomass. Under these conditions the maximal enzyme activation (by 50-55 percent) is simultaneously observed. Basic properties of glucose isomerase fixed inside the cell are studied in comparison with the enzymic cell-free extract of this enzyme. The pH-optimum for preparations coincides and is observed at pH 7.5; the temperature optimum for the soluble enzyme is 70 degrees C, and for the intracellular enzyme it is higher by 5 degrees C. Thermostability of the intracellular enzyme is also higher than that of the soluble one. The Michaelis constants are calculated for the glucose isomerase preparations in a form of producer cells and enzymic extract: they equal to 0.375 M and 0.285 M, respectively. A comparison of properties permits considering intracellular glucose isomerase as an immobilized enzymic preparation.
Subject(s)
Aldose-Ketose Isomerases , Carbohydrate Epimerases/metabolism , Streptomyces/enzymology , Enzyme Activation , Hot Temperature , Hydrogen-Ion ConcentrationABSTRACT
Catalytic activity and stability of glucoamylases immobilized by different methods (adsorption, covalent binding) are studied comparatively. The highest stability is shown to be obtained under covalent binding. The binding efficiency and immobilized glucoamylase properties depend on the nature of insoluble carrier and a purification degree of the enzyme preparations. The choice of the cross-linking agent promoting a binding between the enzyme and the carrier is very significant. The activity and stability of immobilized glucoamylases obtained when using different cross-linking agents rise in such a sequence: 2,4-toluylenediisocyanate, cyanurochloride, glutaric dialdehyde, gossypol. Catalytic properties and stability are determined for soluble and immobilized glucoamylase forms from different sources.
Subject(s)
Enzymes, Immobilized , Glucan 1,4-alpha-Glucosidase , Glucosidases , Catalysis , Cross-Linking Reagents , Drug Stability , In Vitro Techniques , MethodsABSTRACT
The paper is concerned with conditions of glucoamylase binding with silanized silochrome using gossypol, dialdehyde isolated from cotton-plant. Kinetic properties of the immobilized enzyme are studied. The enzyme pH optimum does not change with immobilization and the temperature optimum is shifted from 50 degrees to 60 degrees C; a certain increase of the seeming Km is also observed. A high yield of the enzyme activity in immobilization evidences for the possibility of using gossypol as a binding agent in glucoamylase immobilization.
Subject(s)
Glucan 1,4-alpha-Glucosidase , Glucosidases , Catalysis , Enzymes, Immobilized , Gels , Gossypol , Hydrogen-Ion Concentration , Kinetics , Silica Gel , Silicon Dioxide , TemperatureABSTRACT
The beta-fructofuranosidase preparation was mechanically immobilized. The enzymic preparation with fillers was applied to spheric particles of silicagel by rolling in the pelleting apparatus and the particles obtained were coated with semipermeable polyvinyl acetate film. As compared to the soluble enzyme the temperature optimum of the immobilized preparation is 10-15 degrees C shifted towards an increase and pH-optimum remains unchanged. The regions of pH-stability of immobilized and free beta-fructofuranosidases coincide. An increase in the apparent Km due to immobilization evidences for a diffuse control in kinetics of the preparation action, which is also confirmed by the presence of the induction period in the "reaction product in external solution-time" curve.
Subject(s)
Enzymes, Immobilized/metabolism , Glycoside Hydrolases/metabolism , Sucrase/metabolism , Aspergillus/enzymology , Drug Stability , Kinetics , Temperature , beta-FructofuranosidaseABSTRACT
The article deals with the process of immobilizing the enzymic preparation amylosubtilin G10x by the carriers activated with 2,4-toluylenediisocyanate and cyanurchloride which were obtained on the basis of silanized sylochrome. The 2,4-toluylenediisocyanate activated carrier is shown to be high-effective in immobilization. The activity of the preparations immobilized by the carrier activated with 2,4-toluylenediisocyatate is 75 units per 1 g of carrier; for the preparation immobilized on the carrier activated with cyanurchloride it is equal to 2.9 u/g. The specific activity is 3.1 and 0.9 u/mg, respectively. Immobilization on the tested carriers decreases the enzymic preparation thermostability.
Subject(s)
Amylases/metabolism , Enzymes, Immobilized/metabolism , Drug Stability , Kinetics , Methods , Temperature , Toluene 2,4-Diisocyanate , TriazinesABSTRACT
A new method is suggested for immobilizing enzymes, catalyzing the splitting of low-molecular substrates. It consists in applying the layer of the enzymic preparation with a filler and a stabilizer onto the inert carrier by the rolling-up method in the dredging box and the subsequent coating of particles with a semipermeable film. The efficiency of the mentioned method is examined in two enzymic preparations: beta-galactosidase and beta-fructofuranosidase. Its advantages are discussed, the main of which are the simplicity of technology possibilities of using the enzymes technical preparations, maximal preservation of native properties.
