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  • Arjuman Surti
  • Mugdha Taral


Bacillus sp. AM251, feather, keratinase, keratin, poultry, optimization


The poultry industry contributes to immense amounts of feather waste, over 90% of which is keratin. Although these industrial byproducts can be used as animal feed due to their high nutritional value, they are often landfilled or composted due to their low decomposition. The present study was carried out to isolate and identify a potential keratinase-producing bacterium from soil and waste water samples and to optimize cultural and physicochemical conditions to maximize enzyme production. The bacterium with the highest enzyme activity among the 17 isolates obtained in our study was identified as Bacillus sp. AM251. Optimal enzyme production was observed in media with the following composition (in g/L); NaCl (0.5), KH2PO4 (0.7), K2HPO4 (1.4), MgSO4 (0.01), CaCl2 (0.5), ammonium sulphate (2.5) and feather (10); pH 7.0. The optimum physicochemical parameters were determined to be 7.5% inoculum size, 37°C incubation temperature and shaking conditions (200 rpm). Characterization studies showed that the enzyme is a 43kDa serine protease with optimum activity at 50°C and pH 8.0. As an application of the enzyme keratinase, we also studied its substrate specificity and depilatory effect on goat skin. Both studies showed good enzyme activity. However, another study conducted to determine the use of enzyme-treated feather meal as an alternative to yeast extract and peptone for the growth of microorganisms in the laboratory showed limited applications. Overall, the results of our study show that the strain Bacillus sp. AM251 has great potential as a keratinase producer that can be used for bioremediation of feathers in landfills, preparation of animal feed or as a depilatory agent.


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How to Cite

Surti, A., & Taral, M. (2024). STUDY OF OPTIMIZATION, CHARACTERIZATION AND APPLICATIONS OF KERATINASE PRODUCED BY A BACILLUS STRAIN. Journal of Applied Biological Sciences, 18(2), 143–161. Retrieved from