Innitial Study on Keratinase Production by Bacillus sp. MD24 and Salinivibrio proteolyticus DV TG6 Consortium Hanifatul Azizah and Suharti Suharti
State University of Malang
Abstract
Chicken feathers are waste containing 82 percent protein in the form of keratin that enzymatically can be degraded by a class of protease called keratinase. Bacillus sp. MD24 and Salinivibrio proteolyticus DV TG6, both were able to degrade chicken feathers at 37C, and pH 8. This condition offer possibility to combine both organism as a consortium to work synergistically in degrading chicken feathers. This paper reports our work on the production of keratinase by Bacillus sp. MD24 and Salinivibrio proteolyticus DV TG6 consortium. This paper also reports our work on improving keratinase by the consortium through addition metal ions and additional carbon sources. The keratinase production was performed by sub-merged fermentation and Co, Ni, Mn, Ca, Zn, Cu, and Fe were tested as metal ions supplement during fermentation. Various additional carbon sources were tested including glucose, corn flour, coconut pulp, and corn cobs. The result showed that keratinase production by the consortium was slightly increase compared to its member alone. Interestingly, although Mn, Ca, Zn, Cu, and Fe ions improved keratinase production by Salinivibrio proteolyticus DV TG6 it suppressed keratinase production by Bacillus sp. MD24 and none of those metal ions improved keratinase production by the consortium. However, Mn ion did not suppress the enzyme production. Coconut pulp shortened keratinase production by Salinivibrio proteolyticus DV TG6 but not for Bacillus sp. MD24 and the consortium. Overall, it concluded that the consortium did not work well. The keratinase production by Salinivibrio proteolyticus DV TG6 alone was improved by adding some metal ions and coconut pulp, however its activity was relatively low compared to the production by Bacillus sp. MD24 and the consortium. Salinivibrio proteolyticus DV TG6 was originated from salt pond and which might be better to produce keratinase under higher salt concentration.
Keywords: metal ions, keratinase, chicken feather, fermentation
