Thermostable α-amylase from Lignocellulosic Residues Using Bacillus amyloliquefaciens

In this study, thermostable high performance α-amylase was synthesized from lignocellulosic residues using Bacillus amyloliquefaciens. For this purpose, hydrolysates of wheat bran, rice bran and sugarcane bagasse were used as substrate for enzyme production. The maximum enzyme production was achieved in the medium containing hydrolysate of wheat bran. In order to enhance α-amylase production, the medium composition was optimized in terms of supplementary carbon and nitrogen sources. Enzyme activity in the optimized medium (208.94 U mL-1) was considerably higher as compared to non-optimized medium (76.22 U mL-1). The activity and stability of the synthesized enzyme was assessed in various temperature and pH environments. The optimum condition for highest enzyme activity (pH 7 and 70 ◦C) and stability (pH 7 and 50 ◦C) was determined. The effect of various metal ions on the α-amylase activity was investigated. The enzyme activity enhanced in the presence of Mg, Mn, Zn, Na, Cu, Ca ions, while Fe ion hindered the enzyme activity.