ABSTRACT
Glucoamylase (commercial preparation Glucavamorin) was immobilized by sorption on a carbon support Sibunit. Starch saccharification by the resulting biocatalyst (dextrin hydrolysis) was studied. Investigation of the effect of adsorptional immobilization on kinetic parameters of glucoamylase, including the rate constant of thermal inactivation, showed that immobilization of Glucavamorin on Sibunit resulted in a thousandfold increase in glucoamylase stability in comparison with the dissolved enzyme. Presence of the substrate (dextrins) in the reaction mixture had a considerable stabilizing effect. Increase in dextrin concentration increases the thermostability of the immobilized enzyme. The overall factor of glucoamylase stabilization adsorbed on Sibunit with the presence of 53% dextrin solutions in comparison with the dissolved enzyme approximated 10(5). The biocatalyst for starch saccharification made on the base of Subunit-adsorbed Glucavamorin had a high operational stability. Its half-inactivation time at 60 degrees C exceeded 30 days.
Subject(s)
Carbon/chemistry , Enzymes, Immobilized/chemistry , Glucan 1,4-alpha-Glucosidase/chemistry , Catalysis , Dextrins/chemistry , Enzyme Stability , Hydrolysis , Kinetics , Starch/chemistry , Surface PropertiesABSTRACT
Heterogeneous biocatalysts of starch conversion based on glucoamylase and carbon-containing carriers were obtained, and their biocatalytic properties in enzymatic hydrolysis of corn dextrins were studied. It was shown that the morphology of the surface carbon layer of carriers markedly affected the properties of biocatalysts. Glucoamylase that was immobilized by adsorption on the surface of carriers covered with a layer of catalytic fibrous or pyrolytic carbon had the maximum enzymatic activity and stability, whereas the biocatalysts prepared on the basis of carriers that had no carbon layer or were covered with graphite-like surface carbon had a low activity and stability.
Subject(s)
Aspergillus/enzymology , Dextrins/chemistry , Enzymes, Immobilized/chemistry , Glucan 1,4-alpha-Glucosidase/chemistry , Aluminum Oxide/chemistry , Carbon/chemistry , Catalysis , Glass/chemistry , Hydrolysis , Minerals/chemistryABSTRACT
Yeast membranes were obtained by autolysis of various strains with relatively high invertase activity. Heterogeneous biocatalysts for sucrose inversion were made of the yeast membranes and granulated carbon-containing supports made of common natural materials: expanded clay aggregate (ECA), sapropel, and lignin. The properties of these biocatalysts were studied. It was shown that the biocatalyst activity and stability of the immobilized yeast membranes increased with reference to the initial ECA, independent of the structure of the carbon layer synthesized on the support surface. Heterogeneous biocatalysts prepared by adsorption of yeast membranes on sapropel had the greatest activity and stability, whereas lignin-based biocatalysts were relatively unstable.
Subject(s)
Cell Membrane/metabolism , Sucrose/metabolism , Yeasts/metabolism , Adsorption , Catalysis , Microscopy, Electron , Yeasts/ultrastructureABSTRACT
Carbon-mineral sorbents successfully combine a high mechanical resistance of the mineral matrix and a high activity of carbons. It is possible to prepare a mineral matrix of the wanted structure and use it as the basis for producing carbon-mineral sorbents. SUMS-1 and SUMS-2 are the sorbents of mild action. In other words, they cause no thrombosis, they do not absorb oxygen and protein from blood, and they have almost no destructive effect on the blood cells. The sorbents are highly effective in adsorbing microorganisms and their toxins. Treatment of patients with different diseases (sepsis, meningitis, bronchial asthma, tuberculosis, pneumonia, thyrotoxicosis, pancreatitis, liver coma, different types of poisoning) with the SUMS-1 and SUMS-2 has given satisfactory results.
