Production of Keratinase from a Newly Isolated Feather Degrading Bacillus cereus VITSDVM4 from Poultry Waste

A new feather-degrading bacterium was isolated from soil near poultry waste. Based on the morphological, physiochemical, and phylogenetic characteristics, the keratinolytic bacteria was identified as Bacillus cereus VITSDVM4 (Accession number KJ725087).To enhance the yield of keratinase, the effect of various parameters such as pH, temperature, carbon source, nitrogen source, substrate concentration, inoculum size and incubation time were optimized. The maximum keratinase activity was found to be 134 U ml−1 at pH 7. At 25 °C, it was slightly increased and showed 174 U ml−1 activity. The carbon source, sucrose revealed the maximum enzyme activity of 226 U ml−1. Yeast extract was found to be the altered nitrogen source in the production medium with 271 U ml−1 of enzyme activity. 10 mg of feathers as substrate, 3% of the microbial inoculum and 72 h of incubation enhanced the enzyme production and exhibited a maximum activity of 378, 408 and 453 U ml−1 respectively. The partially purified keratinase showed maximum specific activity of 528.7 U mg−1 as well as visible degradation of feather, hair and nail after 48 h of incubation confirms the keratinolytic activity.