Purification and characterization of a novel and versatile alpha-amylase from thermophilic Anoxybacillus sp YIM 342

摘要

An extracellular thermophilic alpha-amylase (1, 4-alpha-D-glucanohydrolase, EC 3.2.1.l) from Anoxybacillus sp. YIM 342 was partially purified by ultrafiltration followed by ammonium sulfate fractionation and dialysis. This procedure was followed by a single purification step using gel filtration chromatography to give a 10.41% yield, 1912.2U/mg specific activity, and 32-fold purification enrichment. The molecular mass of the purified a-amylase was determined to be 68 kDa using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The optimum temperature and pH of the a-amylase activity were 80 degrees C and 9.0, respectively. Furthermore, the high hydrolysis rate toward amylose and amylopectin suggested the enzyme has significant potential for applications in starch degradation. The K-m and V-max of the amylase toward soluble starch was 4.18 mu g/mL and 7.48 mmol/min/mg, respectively. This enzyme hydrolyzes soluble starch to glucose, maltose, and maltotriose, indicating that the amylase represents a promising candidate for applications in the biofuel industry.