Biodegradation of keratinous waste by Chryseobacterium sp. RBT isolated from soil contaminated with poultry waste

In the present study, a feather degrading bacterial strain was isolated from poultry waste disposal site, Kolhapur, India. The bacterium was identified as Chryseobacterium sp. RBT using 16S rRNA gene sequence analysis. Chryseobacterium sp. RBT showed rapid hydrolysis of native feathers within 30 h and produced the highest level of keratinase activity (98.3 U/ml). Keratin containing wastes viz. silk, human hair, wool and chicken feathers were tested for keratin degrading ability of the bacterium. Amongst the tested substrates, the Chryseobacterium sp. RBT showed more specificity towards chicken feathers (98.6% degradation) with maximum keratinase activity (98.3 U/ml) and solubilized protein concentration (3.84 mg/ml). Effect of various physico-chemical parameters (temperature, pH, carbon and nitrogen sources) on keratinase production was monitored. The maximum keratinase activity was observed at pH (8.6) and temperature (50 °C). Molasses (1.0% w/v) acted as an inducer and enhanced the keratinolytic activity by two fold, while starch worked as an inhibitor. The goat skin when treated with crude keratinase enzyme (2% v/v), showed complete dehairing within 12 h. Hence, Chryseobacterium sp. RBT shows potential as a candidate for treating the keratinous waste in an ecofriendly manner.