Stability and activity of immobilized hydrolytic enzymes in two-liquid-phase systems: acid phosphatase, beta-glucosidase, and beta-fructofuranosidase entrapped in poly(2-hydroxyethyl methacrylate) matrices.

Enzyme storage stability and hydrolysis yield were measured in experiments carried out with three model hydrolytic enzymes: acid phosphatase (EC 3.1.3.2), beta-glucosidase (EC 3.2.1.4), and beta-fructofuranosidase (EC 3.2.1.26) entrapped in hydrogels of poly(2-hydroxyethyl methacrylate). Runs were performed at 30 degrees C, under intensive stirring (500 rev min-1), in 50% v/v biphasic media prepared with buffer and organic solvents, whose log P value varied from 0.68 to 8.8. Storage stability was also monitored in the pure solvents. The small average particle size (125-210 microns) and the intensive stirring eliminate hindrances of intra- and interphase mass transfer resistances. The hydrophilic matrix protects the enzymes against thermal and chemical deactivation, thus allowing good production per unit weight of biocatalyst. In biphasic media, storage stability, with the exception of acid phosphatase, was not dependent on solvent polarity. On the contrary, a significant trend was observed when the enzymes were stored in neat organic solvents.