Alkaline protease from Bacillus cereus VITSN04: Potential application as a dehairing agent

The objective of this work is to use protease enzyme as an ecofriendly alternative to chemicals in dehairing. An alkaline protease producing bacterium was isolated from protein-rich soil sample. The bacterium was identified as Bacillus cereus VITSN04 by 16S rRNA gene sequencing method. Growth characteristics and protease activity were studied in yeast, malt, beef, nutrient broth and soybean casein digest media and the enzyme secretion was found to correspond with growth. Maximum protease production was obtained in soybean casein digest medium at 16 h with the activity of 200.1 ± 0.68 U/ml and a correlation coefficient of 0.965 between growth and enzyme production. The crude enzyme was found to have maximum activity at 30°C and pH 8.0. The protease was purified by ammonium sulphate precipitation, Sephadex G-50 and G-100 gel filtration chromatography. The purified protease was homogeneous on non-denaturing PAGE and its molecular weight was estimated to be 32 kDa. The purified protease was of the serine type as it was inhibited by phenylmethylsulphonyl fluoride. The crude enzyme preparation was found to be effective in dehairing goat skins in leather processing.