Purification and characterization of an extracellular amylase from Lactobacillus plantarum strain A6

Extracellular amylase from Lactobacillus plantarum A6 was purified by fractionated precipitation with ammonium sulphate and by anion exchange chromatography. The homogeneity of the purified fraction was tested by polyacrylamide gel electrophoresis and showed multiple amylase forms. A major form had an estimated molecular weight of 50 kDa. It was identified as an α‐amylase, with an optimum pH of 5.5, an optimum temperature of 65°C and K m value of 2.38 g l ‐1 with soluble starch substrate. The enzyme was inhibited by N ‐bromosuccinimide, iodine and acetic acid. The enzyme activation energy was 30.9 kJ mol ‐1 .