Heterologous expression and biochemical characterization of novel multifunctional thermostable α-amylase from hot-spring metagenome.

Hot-springs are regarded as the best source of industrially significant biocules and one of the unique locations for extremophiles. The α-amylase is one of the most important enzymes used in starch consuming industries, where the need of thermostability is paramount. In this study, the full metagenome sequences obtained from the soil of Tuwa hot-spring (Gujarat, India) were examined for the presence of several thermostable enzymes using bioinformatic techniques. The whole gene sequence for α-amylase was found from the metagenome. The α-amylase gene was amplified, cloned, and expressed in Escherichia coli and further characterized in vitro. The rm-α-amylase was found optimally active at 60 °C and at pH 6.0 and showed significantly high activity in 0.1 mM Co2+ as well as in other heavy metal ions without any effect on its thermostability. Apart from α-amylase activity the purified rm-α-amylase was also shown to hydrolyse agar, xylan, pectin, alginate and cellulose. To our knowledge, this is the first report of a new, multifunctional, thermostable amylase that was discovered from the hot-spring metagenomes. Owing to their multifunctionality, resilience towards high temperature and heavy metal ions, stability with solvents, additives and inhibitors, rm-α-amylase can be exploited for a variety of biotechnological applications. • Studied an unique multifunctional α-amylase directly isolated from the hot spring metagenome of a soil sample from Tuwa • Protein properties of the rm-α-amylase suggest that the enzyme belongs to the -amylase from the bacterium HR18 • Expression, purification and activity check showed amylase, xylanase, agarase, pectinase, cellulase and alginate lyase activity • The ɑ-amylase has an optimal temperature of 60 °C, a pH 6, solvent tolerant, and stable in additives, inhibitors, detergents [ABSTRACT FROM AUTHOR]