Isolation of Bacillus Strains with Keratinolitic Activity

Environmental safety and economic feasibility determine the search for new ways of processing waste in poultry farms. Most of this waste is down and feathers, which are 90% β-keratin. Feathers can be a valuable source of amino acids and peptones when properly processed. The most effective is enzymatic treatment of feather keratin. The search for new strains producing keratinolytic enzymes seems to be a promising direction. On the territory of the poultry farm, 4 strains were isolated from the places of accumulation of feathers. They are able to use chicken feathers as their sole source of organic matter. Based on morphological, genomic, and proteomic analyzes, the isolated strains were identified as Bacillus sp. It was found that the strains secrete proteolytic enzymes that hydrolyze collagen, casein, β-keratin and do not hydrolyze bovine serum albumin. Feather hydrolysis experiments showed that the Bacillus sp. A5.3 possesses maximum keratinolytic activity, and on the second day, the destruction of the second order barbs is observed. The keratinase activity of the strain on azokeratin after an hour of incubation on feather medium was 27.4 U/ml. The optimal conditions for the complex of secreted proteolytic enzymes are pH 7.0-8.0 and temperature 35-40 °C. The isolated Bacillus sp. A5.3 strain is a promising source of proteases and keratinases.