Extracellular enzyme production by indigenous thermophilic bacteria: Partial purification and characterization of α-amylase by Bacillus sp. WA21

Thermostability is a characteristic of most of the enzymes available for bulk industrial usage. thermophilic microorganisms are of special interest as a source of novel thermostable enzymes. a total of 50 bacterial strains,isolated from local hot springs and ash samples were screened for the extracellular enzyme production including amylase,lipase,esterase,cellulase and β-galactosidase. as a follow up,studies on α-amylase were carried out with a bacterial strain identified as bacillus sp. wa21 (from hot spring) on the basis of maximum zone of starch hydrolysis in agar plate medium. bacillus wa21 showed growth over a wide range of temperature (35-55°c) and ph (3-11) with optimum being 45°c and ph 6. maximum enzyme production was observed after 144 hours. the enzyme was found optimally active at 55°c and ph 6. temperature stability profile revealed that enzyme α-amylase retained more than half of its activity at 85°c and between ph 5-9. thus,bacillus wa21 may be regarded as a promising source of α-amylase for biotechnological and industrial applications.