Sheep wool protein hydrolysate: a new peptone source for microorganisms

BACKGROUND: Peptones are one of the most expensive components of microbial culture media. The present study was performed to produce microbial peptone from sheep wool using a new chemical process. RESULTS: Wool peptone (WP) was found to have high protein (67.8 g per 100 g) and ash (29.2 g per 100 g) contents. Glutamic acid was the most abundant amino acid inWP with a content of 8175 mg per 100 g). Wool peptone (WP) also had a high content (5042 mg per 100 g) of cystine, a sulphur-containing amino acid. Optimal concentration of WP was determined as 5 g L-1 for the fungi and 6 g L-1 for the bacteria. Staphylococcus aureus showed very poor growth performance in WP medium. Growth performances of Saccharomyces cerevisiae, Bacillus subtilis and Penicillium chrysogenum were at moderate levels in WP medium. The best growth performance for Aspergillus niger was observed in WP medium with a biomass production of 8.17 g L-1. Second best growth performance for Escherichia coli was achieved with WP among the tested peptones. CONCLUSION: Wool peptone (WP) was shown to be a good growth substrate, especially for A. niger and E. coli. This is the first investigation on use of wool as peptone source or substrate for microorganisms. (C) 2016 Society of Chemical Industry