Molecular cloning and characterization of a halotolerant α-amylase from marine metagenomic library derived from Arabian Sea sediments.

Functional screening of a metagenomic library of marine sediment revealed an amylolytic clone BTM109. This report states the purification and characterization of a moderately halotolerant α-amylase, with more than 51% activity in 2.5 M NaCl. The molecular mass of purified protein was determined to be 55.7 kDa by MALDI-TOF MS. The optimum pH for enzyme activity was pH 7 and temperature for maximal activity was 40 °C. At 5 mM concentration, Ca2+ enhanced the enzyme activity indicating that the enzyme is a Ca2+ dependent α-amylase which was confirmed by the starch hydrolysis pattern using TLC. These physico-chemical properties support the suitability of this enzyme for various industrial applications.