The invention provides novel biologically pure cultures of microorganisms high in protease activity and capable of decomposing proteins recalcitrant to proteolysis as contained in garbage, waste water, organic waste liquids, industrial wastes and the like, a protease produced by such microorganisms and capable of decomposing proteins recalcitrant to proteolysis, and a method of utilizing the same. The novel culture is of a soil-derived microorganism belonging to Streptomyces sp., or a strain derived therefrom, which produces a protease capable of efficiently decomposing proteins recalcitrant to proteolysis as contained in waste water, organic waste liquids, industrial wastes and so forth.