Abstract
Keratinous waste is the bulk by-product of various livestock industries. Slow natural degradation of keratin and less efficient chemical hydrolysis imposes challenge for the search of alternative recycling methods. Keratin degrading microbes hydrolyse keratin to soluble peptides and amino acids. Bacillus aerius NSMk2 showed great potential for hydrolysis of chicken feather waste. Bacillus aerius NSMk2 cells grown in phosphate buffer supplemented with chicken feathers showed high disulfide reductase activity and release of sulfhydryl groups. The release of proteins and amino acids were statistically optimized at varied pH (4.0-11.0), temperature (30.0-45.0 °C) and agitation (100-250 rpm), and maximum release was recorded at pH 7.5, temperature 37 °C and shaking (175 rpm). FTIR and SEM showed sulfitolysis and extensive keratinolysis of feathers resulting in complete hydrolysis of white chicken feathers after 84 h. MALDI-TOF mass spectrometry confirmed the release of low molecular weight peptides in the range of 399 to 3289.4 m/z. The present study demonstrates management of otherwise hard-to-degrade keratinous waste and simultaneous nutritional enhancement of waste chicken feathers to value-added hydrolysate that can be used in livestock feed formulations or biofertilizer in agro-industry.