Optimization of process parameters for -amylase production under solid-state fermentation by Bacillus Cereus MTCC 10202

摘要

An α-amylase producing bacterial strain was isolated from sago factory effluent discharged soil and identified as Bacillus cereus. Production of extracellular α-amylase by B. cereus was studied in solid-state fermentation. Different substrates like wheat bran, maize bran, corn bran, millet bran, rice bran, greengram bran, blackgram bran, cassava peel powder, cotton seed oil cake, coconut oil cake, sesame oil cake and groundnut oil cake were screened to select the suitable substrate for the production of α-amylase. Among the agro-wastes, wheat bran was found to be the best substrate. Various physical and chemical parameters were optimized. Maximum α-amylase yield was achieved at pH 7 with inoculum level of 10% at 50°C and an incubation period of 72 h. The optimum ratio of substrate to moisture level was found to be 1:2 and substrate weight to flask volume was 1:50. Supplementation of starch at 1% (w/w) concentration and yeast extract at 1.5% (w/w) concentration resulted in maximum production of α-amylase. Calcium chloride at a concentration of 1% (w/w) was found to stimulate α-amylase production. Thus, B. cereus produced a high titre of α-amylase in solid state fermentation using inexpensive agro-residue under optimized conditions.