Study on the fermentation conditions and the application in feather degradation of keratinase produced by Bacillus licheniformis

Abstract

The submerged fermentation medium was optimized in order to improve the keratinase activity produced by Bacillus licheniformis TCCC 11593. The keratinase showed maximum activity 98.0 U/mL after 48 h fermentation in 50 °C when adding 1 g/L maltose and 1.5 g/L NH4Cl as the supplement of carbon and nitrogen sources. The optimal feather quantity was 20 g/L in fermentation. Ca2+ and Mn2+ inhibited the keratinase activity in fermentation medium, while keratinase activity was improved by adding 0.3 g/L Mg2+ to fermentation medium. At the same time, it was found that the complement of alkaline protease and neutral protease further improved the feather degradation in fermentation process. The total amino acid yield can reach 167.43 mg/g. © Springer-Verlag Berlin Heidelberg 2014.