Bioconversion of feather and production of alkaline protease for detergent and dehairing applications

Annually the poultry industry releases millions of tons of feather waste into the environment. With a protein content of 91%, feather offers huge potential to serve as an animal feed supplement. However, keratin, the main protein component of feather, is highly resistant to hydrolysis by animal and plant proteases. The use of physicochemical methods to hydrolyze feather, in addition to being expensive, cause decomposition of some amino acids. Thus, microbial bioconversion of feather offers an attractive option for the production of useful products. In this study, an alkaliphilic feather degrading strain, Bacillus pseudofirmus BCC026 was isolated from the Makgadikgadi salt pan in Botswana. When grown in liquid culture containing feather as the sole source of nitrogen, it resulted in complete solubilization within 48 to 72 h. The organism also produced an alkaline protease, soluble proteins, and peptides/amino acids into the culture medium. The enzyme showed optimum activity in the pH range of 7.5–10.5 and at 70°C. It was also active and stable in commercial detergents and resulted in complete removal of stain from cotton fabrics. The enzyme was also effective in removing hair from goatskin indicating its potential for dehairing application. Microbial growth substrates are known to account for a significant proportion of the production cost of industrial enzymes. Since protease BCC026 was produced using feather, a cheap and readily available resource, enzyme production cost could be significantly reduced. Moreover, after enzyme recovery, the soluble proteins and peptides/amino acids in the filtrate could be used for different applications.