Capacity of hyperthermophilic Crenarchaeota for decomposition of refractory proteins (α- and β-keratins)

Anaerobic thermophilic archaea of the genera Thermogladius and Desulfurococcus capable of α- and β-keratin decomposition were isolated from hot springs of Kamchatka and Kunashir Island. For two of them (strains 2355k and 3008g), the presence of high-molecular mass, cell-bound endopeptidases active against nonhydrolyzed and partially hydrolyzed proteins at high values of temperature and pH was shown. Capacity for β-keratin decomposition was also found in collection strains (type strains of Desulfurococcus amylolyticus subsp. amylolyticus, D. mucosus subsp. mobilis, and D. fermentans).