Keratinolytic potential of micromycete Aspergillus clavatus VKPM F-1593 and comparison of its enzymes with the commercial keratinase preparation

Animal husbandry is a rapidly developing branch of agriculture, increasing the volume of production annually, and keratin-containing waste (feathers, bristles) make up the majority of all waste from this industry. The development of methods of environmentally friendly processing of such waste to obtain valuable resources (amino acids and oligopeptides) is an important mission of modern science, including biotechnology. One of the ways to dispose of animal husbandry waste that meets modern trends in the development of a green economy is the use of microorganisms and their enzymes. The possibility of obtaining keratinolytic enzymes of Aspergillus clavatus VKPM F-1593 under deep conditions with various sources of nitrogen and carbon, including with the growth of the producer on animal waste, was studied. The highest target activity (96.1 E) was achieved using mixed carbon and nitrogen sources: inorganic – sodium nitrate, easily digestible organic – fish meal hydrolysate and hard–to-reach organic – ground chicken feather. Varying the content of various substrates in the composition of fermentation media allowed not only to regulate the level of proteolytic activity, but also to reach the peak of producer activity on different days of cultivation. The specific keratinase activity of A. clavatus VKPM F-1593 (pI 9.3) to various protein substrates with the activity of a commercial proteinase K. Both enzymes showed a similar level of activity regarding most of the substrates used. However, protease A. clavatus VKPM F-1593 has a greater overall proteolytic activity, which confirms the prospects of this culture for biodegradation of animal waste.

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