Crosslinked enzyme aggregates (CLEA) of phytase with soymilk proteins

Crosslinked Enzyme Aggregates (CLEA) of phytase (E.C. 3.1.3.8) have been successfully prepared using soymilk as protein feeder. Compared to total initial activity of 4428 units used for immobilization, the recovered activity in the CLEA is enhanced to 8000 units. The CLEA retained 100% phytase activity up to 50 degrees C and 70% activity at 70 degrees C after 6 h incubation while soluble enzyme lost 50% activity at 50 degrees C and 80% at 70 degrees C. Soluble phytase has an optimum pH of 2.1 while immobilized enzyme maintains high level of activity in a broad pH range of 1-6. CLEA also retain 80% activity upon proteolytic hydrolysis with pepsin, pancreatin, trypsin and chymotrypsin, while soluble enzyme loses 40% activity under same conditions. Phytase CLEA were recycled for 5 times without loss in activity using a stirred basket reactor.