Keratinase production and biodegradation of whole chicken feather keratin by a newly isolated bacterium under submerged fermentation

Abstract

A new feather-degrading bacterium PKD 5 was isolated from feather dumping soil and identified as Bacillus weihenstephanensis based on morphological and physiochemical characteristics as well as 16S rRNA gene analysis. Extracellular keratinase was produced during submerged aerobic cultivation in a medium containing chicken feather as sole carbon and energy source and supplemented with salt solutions (NaCl 5.0, MgSO₄ 1.0, K₂HPO₄ 1.0, (NH₄)₂SO₄, 2.0 g/l). The optimal conditions for keratinase production include initial pH of 7.0, inoculum size of 2% (v/v), and cultivation at 40 °C. The maximum keratinase production and keratinolytic activity of PKD 5 was achieved after 7 days of fermentation under shaking condition (120 rpm). The enzyme has found application in developing cost-effective feather by-products for feeds and fertilizers. The manuscript first time describes B. weihenstephanensis PKD 5-mediated keratinase production under submerged fermentation and whole chicken feather biodegradation.