Study of proteolytic and keratinolytic enzymes of bacillus sp. A5.3

Abstract

Feathers, as a major part of the waste from the industrial poultry industry, require a special approach for disposal and, at the same time, are of interest as a source of feed protein. Feather biomass consists of 90% β-keratin, hydrolysates of which can be a valuable source of pepton, but feather keratin is highly resistant to most proteolytic enzymes. For hydrolysis, therefore, keratin must be subjected to special treatment, the purpose of which is to break down the compact structure of the keratin molecule to produce polypeptides, peptides and single amino acids.  For enzymatic hydrolysis of keratin, proteases with keratinase activity are used, capable of cleaving keratin disulfide bonds.  A strain of Bacillus sp. A5.3 was isolated from feather waste sites and showed high proteolytic and keratinolytic activity. The strain is able to grow on minimal feather medium and has caseinolytic, collagenase and β-keratinolytic activity. The secretory proteome of the strain was studied using nano HPLC/Q-TOF-MS. As a result, 154 proteins were identified, 13 of which are proteases and peptidases. The genes for 3 proteases and peptidases clpY, clpX and ytjP were amplified from the genomic DNA of Bacillus sp. A5.3, sequenced, and the nucleotide sequence of the genes was deposited in the GenBank database. A study of a strain of Bacillus sp. A5.3 showed that the strain is capable of effective feather degradation and promising as a producer of proteolytic and keratinolytic enzymes.