Effect of indigenous bacterial community on arsenic mobilization in a degraded soil under submerged conditions

The complete gene (amy) that encoding a raw starch digesting α amylase (BYXA) from Bacillus sp. YX-1 was cloned, sequenced and expressed in Escherichia coli. The amy gene consisted of 1545 base pairs and encoded a protein of 514 amino acid residues with a calculated molecular mass of 58 kDa. The recombinant protein was purified by Ni2+ affinity chromatography and subsequently characterized. The optimal pH and temperature for the purified recombinant enzyme were 5.5 and 45 °C, respectively. The enzyme showed stability over a pH range of 5.0-11.0 and below 50 °C. The enzyme exhibited remarkable digestibility towards raw starch at low pH values, which was valuable in starch processing industry.