Keratinase of an anaerobic thermophilic bacterium Thermoanaerobacter sp. strain 1004-09 isolated from a hot spring in the Baikal Rift zone

A thermophilic anaerobic bacterial strain 1004-09 belonging to the genus Thermoanaerobacter and capable of growth on protein substrates such as albumin, gelatin, casein, and alpha and beta-keratins was isolated from the Urinskii hot spring (Barguzin river valley, Republic of Buryatia, Russia). A 150-kDa serine proteinase was revealed in the strain supernatant; it exhibited optimal activity at 60 degrees C and pH 9.3 and was capable of keratin hydrolysis. A number of characteristics for the strain 1004-09 keratinase were established including activation by SDS and NaCl and residual activity (15% to the activity of the intact protein) in the presence of 10% ethanol and acetone.