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Evaluation of brewer's spent grain as a substrate for production of hydrolytic enzymes by keratinolytic bacteria
Author(s) -
Łaba Wojciech,
Piegza Michał,
KawaRygielska Joanna
Publication year - 2017
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.5134
Subject(s) - proteases , bacillus subtilis , bacillus cereus , cellulase , cereus , bacteria , bioconversion , protease , amylase , biochemistry , hydrolysis , food science , enzyme , chemistry , substrate (aquarium) , bacillus (shape) , microbiology and biotechnology , biology , fermentation , ecology , genetics
BACKGROUND Brewer's spent grain ( BSG ) is the most abundant by‐product of the brewery industry. The current massive output of BSG requires novel methods of bioconversion into added‐value products. Its composition and high biological value, i.e. high protein content, allows for various biotechnological applications. RESULTS Here, BSG was used as a substrate for submerged cultivation of keratinolytic bacteria, Bacillus cereus PCM 2849 and B. subtilis PCM 2850. The strains biosynthesized proteases to decompose proteins within the substrate and amylases to degrade residual starch. Enzymes degrading structural polysaccharides were also present. Bacillus cereus produced multiple proteases with high activity, predominantly with molecular weight (mw) >70 kDa , depending on the presence of minerals. Bacillus subtilis biosynthesised proteases of wide mw range, independently of the mineral components. Crude culture fluids of both bacteria exhibited proteolytic activity on a variety of proteins, including keratins. Structural deterioration of the BSG in microbial cultures was observed. CONCLUSION The BSG was a suitable medium component for the production of bacterial proteases and polysaccharide‐degrading enzymes. Two keratinolytic Bacilli, grown in the presence of BSG utilized residual proteins and biosynthesized proteases exhibiting keratinolytic activity. Bacillus cereus dominated in terms of protease production, while B. subtilis presented higher production of amylases, cellulases and xylanases. © 2016 Society of Chemical Industry