Abstract

ISOLATION AND CHARACTERIZATION OF β-GALACTOSIDASE PRODUCING BACILLUS SUBTILIS FROM MILK

Gangadhar C. Gouripur and B. B. Kaliwal*

Abstract

The enzyme β-galactosidase has tremendous potential in research and application in various fields like food, bioremediation, biosensor, diagnosis and treatment of disorders. The sources of the β- galactosidase are microorganisms, plants and animals. In the present study β-galactosidase producing bacteria was isolated from milk and milk products. Bacteria were tested for their ability to hydrolyze 5- bromo-4-chloro-3-indolyl-β-D-galactosidase (X-Gal) and O-nitro phenyl-β-D-galactopyranoside (ONPG). Further, it was identified by conventional methods and 16S rRNA gene sequencing as Bacillus subtilis. The production of β-galactosidase by Bacillus subtilis was found to be optimum at temperature of 37ºC and pH -7.0 after 48 hrs of incubation. The various carbon, nitrogen and metal ion sources used in the present study such as Xylose, Yeast extract and MgSO4.7H2O ion increased the production of enzymes. Under optimal conditions, β-galactosidase enzyme produced by Bacillus subtilis was partially purified using ammonium sulphate precipitation, dialysis and SDS-PAGE in the molecular weight of the enzyme was found to be ~ 60 kDa.

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