Production of alpha-galactosidase by aspergillus oryzae through solid-state fermentation and its application in soymilk galactooligosaccharide hydrolysis

Abstract

?-Galactosidase was produced by Aspergillus oryzae on red gram plant waste-wheat bran based media in solidstate fermentation (SSF). Optimum temperature for ?-galactosidase production was 35°C and upto 4 cm of bed height of substrate had no inhibitory effect on enzyme production. Hydrolysis of galactooligosaccharides in soymilk was carried out by ?-galactosidase. Optimum temperature and pH for the hydrolysis of raffinose and stachyose of soymilk were 55°C and 5.2-6.2, respectively. The enzymatic treatment for 3 h completely removed the raffinose oligosaccharides in soymilk. Crude extract also showed considerable amount of invertase activity.