Fermentation, Characterization And Application Of A New Keratinase From Bacillus Licheniformis

Keratinase was fermented by Bacillus licheniformis FBK-1. The effects of pH , temperature and metal ions on enzymic activity were investigated. The enzyme was applied on feather degradation, the character of product including molecular weight distribution, protein solubility, pepsin Digestion rate and Amino acid was analyzed. The crude enzyme from Bacillus licheniformis FBK-1 was produced when the feather is the sole source of Carbon and Nitrogen. The time of fermentation is 72 hours, the activity of keratinase is between 600 and 700 unit per milliliter, the optimum conditions of activity were pH9.0 and temperature50℃. The enzyme was stable at pH between 8.0-9.0 and temperature is up to 40℃. The activity was enhanced by Na+,K+,Ca2+,Mg2+, activity is dosc dependent. The wetting chicken feather incubated at 121℃for 1 hour, then hydrolyzed by keratinase production, the dried enzymolysis product powdered, was subject to further analysis, the result indicated 80 percent crude protein , 10 percent of soluble protein and 78 percent of Pepsin Digestion rate. The product possessed same quality with feather meal in the market. The wetting duck feather meal treated in 121℃1 hour was hydrolyzed at 40℃, pH 9.0 for 28 hours by compatible keratinase production, then supernate and precipitate was separated by centrifuge. The precipitate contain 17.96 percent of soluble protein and 88 percent of Pepsin Digestion rate. Except three kinds of amino acid (Lys,Arg,His),the content of rest 14 kinds of amino acid was higher than fish meal. The precipitate can replace fish meal as feedstuff additive. The supernate was applied to a Super Peptide column 10/300 GL, most fraction were eluted behind 6KD. Both supernate and precipitate were subjected into amino acid analysis, the supernate contains 17 kinds of amino acid,which can be material of amino acid and peptide productions. Therefore,the enzyme fermented by Bacillus licheniformis FBK-1 was a new kind of keratinase. It can be used to hydrolyze feather and the enzymolysis product can be applied to amino and peptide productions.