INFLUENCE OF IMMOBILIZATION ON ENZYME-ACTIVITY IN AQUEOUS-ORGANIC COSOLVENT MIXTURES

Four enzymes viz. polyphenol oxidase, trypsin, acid phosphatase and pe roxidase were adsorbed on eudragit-S100, chitin and chitosan. The enzy me activities of bath free as well as immobilized enzymes were assayed in the presence of varying concentrations of some organic cosolvents viz. acetonitrile, tetrahydrofuran, dimethyl formamide and dioxane. In many cases, the enhanced activity observed in the presence of low con centration of organic cosolvent (upto 20%) were greater in the case of immobilized enzymes. In some cases, immobilization led to greater ret ention of enzyme activity in the presence of higher concentrations of an organic cosolvent. It was found that influence of the matrix upon c o-solvent tolerance varies with the solvent but did not correlate with a solvent parameter such as log P. It is shown that adsorption is a g ood approach while preparing immobilized enzymes for working in media where concentrations of organic cosolvents do not exceed about 20%.