Purification and Characterization of α-amylase from a Novel Thermoalkalophilic Strain of Bacillus sonorensis GV2 Isolated from Mushroom Compost

Abstract

A novel thermoalkalophilic α-amylase producing bacterial strain Bacillus sonorensis GV2 |KJ775811.1| was isolated from mushroom compost. The purification of α-amylase was performed through different chromatography techniques. After purification with SDS-PAGE and Sephadex G-75 gel filtration, the molecular weight of monomeric α-amylase was found to be 45 kDa. The enzyme showed an optimal activity over a wide range of temperature and pH of 35-60oC and 7-11, respectively. The effect of divalent ions i.e. Mg2+ and Ca2+ showed a positive increase in enzyme activity. This enzyme is unique in a sense that it also exhibited a considerable raw corn starch hydrolyzing activity at 55oC. The end products when subjected to TLC which were identified as main maltooligosaccharides, proving the endo action of an enzyme. The Vmax and Km values of Bacillus sonorensis GV2 α-amylase were found to be 1347 μmol/mg/min and 3.46  mMol/ml. The MALDI peptide mass fingerprint analysis of the reduced and carboxymethylated amylase digested with chymotrypsin indicated that this partial amino acid sequence was homologous by a score of 6 with UDP transferalyase. All these findings suggests about the potential role of this α-amylase for raw starch degrading applications in the relevant industry.