Solid State Fermentation for Production of Extracellular ?-Galactosidase from Bacillus circulans ATCC 4516

Abstract

Although most microbial enzymes are produced by submerged fermentation, the use of agricultural wastes as substrates in solid state fermentation (SSF) makes the production of enzymes more economical. The use of economic substrates is of great interest for making the enzyme production process significantly cheaper for SFF. The aim of this study was to investigate the effect of some parameters on the production of beta-galactosidase from Bacillus circulans ATCC 4516 using rice bran as substrate in solid state fermentation (SFF) method. Certain fermentation parameters involving incubation time, incubation temperature, inoculum level and initial pH were studied separately. Maximal amount of beta-galactosidase production was obtained at 35% inoculum level, at initial pH of 7.5, at 37 degrees C over 48 h. In addition, various carbon and nitrogen sources were added to fermentation medium and the effect on beta-galactosidase production was investigated. According to the results, carbon and nitrogen sources which added to the environment suppressed the enzyme production.