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Glucoamylase Covalently Bound to Acrylic Carriers
Author(s) -
Wawrzyniak B.,
Krauze J.
Publication year - 1991
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.19910430707
Subject(s) - thermostability , chemistry , immobilized enzyme , hydrolysis , glutaraldehyde , maltodextrin , chromatography , starch , acrylic acid , nuclear chemistry , polymer chemistry , thermal stability , yield (engineering) , copolymer , enzyme , organic chemistry , materials science , polymer , spray drying , metallurgy
Glucoamylase from Aspergillus niger was covalantly bound to three acrylic carriers differing in the content of amino groups, particle size, porosity, etc. Yield of immobilization ranged from 58.7% to 87.0%. Enzyme immobilized on Vinylaff 818 was the most stable. That carrier was a copolymer of butyl acrylate and ethylene dimethacrylate, containing 0.44 mmol/g of amino groups. The immobilized catalyst used for hydrolysis of 40% maltodextrin solution (DE 18.3) retained its initial activity at 50°C for about 33 d. The pretreatment of soluble glucoamylase with low concentrated glutaraldehyde solution (0.13%, 1.4 mg/100 mg of protein) increased the operational stability of immobilized enzyme to about 50 d and its half‐life to 60 d. The immobilization of enzyme on Vinylaff 818 resulted in the slight shift of pH optimum to acid side, though it did not influence the temperature optimum. Thermostability of immobilized glucoamylase in the range of temperature between 50 and 75°C was higher than that of soluble enzyme. Maximum concentrations of glucose in hydrolyzates were obtained in relatively short time. The prolonged hydrolysis of concentrated starch substrate by enzyme immobilized on the porous carrier caused, however, the accumulation of disaccharides with simultaneous reduction of glucose content.