EFFECT OF ORGANIC-SOLVENTS ON STABILITY OF 2 GLYCOSIDASES AND ON GLUCOAMYLASE-CATALYZED OLIGOSACCHARIDE SYNTHESIS

Enzymatic catalysis in nonaqueous media has been significantly developed for several years, and essentially enzymes such as lipases and proteases have been involved. In this paper, the behavior of glycosidases, a model of biocatalysis seldom used in organic media, was investigated. The toxicity of 66 organic solvents for two glycosidases (glycoamylase, beta-galactosidase) and their effects upon the thermostability of these enzymes, were studied. They presented a residual activity of 65-100% after 24 h of incubation at 24-degrees-C in most ethers, alcohols, and esters. However, no correlation was found between enzymatic stability and hydrophobicity of the organic medium whatever the selected parameters (Hildebrand solubility parameter, logarithm of the partition coefficient in octanol/water system) may be. Then D-glucose condensation was investigated with glucoamylase.