Statistical Optimization of a-Galactosidase Production in Submerged Fermentation by Streptomyces griseoloalbus Using Response Surface Methodology

a-Galactosidase production by a novel actinomycete strain Streptomyces griseoloalbus in shake flask culture was optimized using response surface methodology. Screening of variables to find their relative effect on a-galactosidase production was done using Plackett-Burman design. Out of the eleven factors screened, salinity, magnesium sulphate and temperature were found to influence the enzyme production significantly. The optimal levels of these variables and the effect of their mutual interactions on enzyme production were determined using Box-Behnken design. The interaction between salinity and magnesium sulphate concentration was found to enhance a-galactosidase production, whereas temperature exhibited an influence independent of the other two factors. Using this statistical optimization method, the a-galactosidase production was increased from 17 to 50 U/mL.