Integration and Expression of a Thermostable β-galactosidase Gene bgaB in Bacillus subtilis

The thermostable beta-galactosidase gene bgaB from Bacillus stearothermophilus was cloned into E.coli- B.subtilis. shuttle vector pMA5. Then bgaB gene and its regulatory sequence were subcloned to B.subtilis. integrative vector pSAS144 and formed a new integrative vector pSAS144-bgaB.This vector was then transformed to a chloramphenicol. Sensitive host B.subtilis BD170 and the transformants were received on LB agar medium with chloramphenicol to a final concentration of 5 μg/mL.The integrative strain showed thermostable -galactosidase activity of 0.32 U/mg, twice of that from original strain Bacillus stearothermophilus.