Keratinase degrading Bacillus cereus was isolated from the halophilic environment in Tamilnadu, India and keratinase production was optimized using wheat bran substrate. Of the screened bacterial isolates, four were found to have the ability to produce keratinolytic enzyme. The process parameters were optimized using one-variable-at-a-time approach and response surface methodology. Supplementation of 1% lactose supported more keratinase production (120 U/g). Among the selected nitrogen sources, addition of casein significantly enhanced maximum keratinase production (132.5 U/g). Among the ions, manganese chloride significantly enhanced keratinsase production (102.6 U/g), however addition of zinc sulphate and copper sulphate decreased keratinase production. The maximum keratinase production was obtained in the wheat bran medium containing 1% lactose, 0.5% manganese with 80% moisture (292 U/g). Statistics based contour plots were generated to explore the variations in the response surface and to find the relationship between the keratinase yield and the bioprocess conditions.
Keywords: Bacillus cereus; Halophilic; Kerainase; Response surface methodology.