Геномика и биология грибов
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Production and Characterization of Keratinolytic Proteases Produced by Onygena corvina

Yuhong Huang, Peter Kamp Busk,and Lene Lange

Poultry farms produce huge quantities of feather waste that causes serious local disposal and accumulative problems and results in environmental pollution. Feathers are composed of β-keratin rich protein and are highly resistant to degradation. The feather degradation potential of the non-pathogenic fungus Onygena corvina was investigated by cultivating this fungus in a medium with duck feathers as the sole carbon and nitrogen source. O. corvina secreted a high level of alkaline protease and keratinase sufficient for degrading duck feathers completely. The optimal conditions for feather keratinolysis were 25ºC, initial pH 8 and feather concentration of 15 g/l. The maximum protease and keratinase activities were found to be 1435 and 72 U/ml, respectively. The protease was active over a broad pH (pH 6-11) and temperature (40-60ºC) range. The keratinase was sensitive to serine protease inhibitors and organic solvents and inhibited by most metal ions, but was stimulated by Ca2+ and Fe2+. Zymogram analysis showed that O. corvina secreted mainly proteases with molecular weight of approximately 35 and 20 kDa. Compared to the fungus Trichoderma asperellum, O. corvina showed higher potential and could be of relevance for bioconverting feather waste into high value products.