Abstract: Protease can be applied in dehairing process of leather industry as an eco-friendly product. We aim to clear the dehairing performance and the process of enzymatic dehairing of JW-3 protease produced by recombinant strain WB800N/pHT43-npr,and to provide technical support for clean technology of leather manufacture. The thermostability and pH value tolerance of JW-3,as well as the effects of metal ions and chemicals on its enzyme activity were investigated. Meanwhile,the ability of enzymatic hydrolysis on collagen,and the comparison between enzymatic dehairing and lime-sulfide dehairing process on cowhide were evaluated. Results showed that JW-3 protease was in poor thermal resistance that enzyme activity began to decay after remaining 1 h at 40℃,and presented solid stability at pH 6 and 7,and was stable in the surfactant of Triton X-100,Tween20,Tween80;moreover,metal ions of Ca²⁺,Mn²⁺ activated its activity. Furthermore,JW-3 protease was incapable of hydrolyzing collagen,and showed the equivalent dehairing performance with lime-sulfide process,also by which nondestructive depilated hair could be recycled. Thus,JW-3 protease can complete cowhide hair removal process,but not hydrolyze the collagen of cowhide,and can be used as an environmentally friendly alternative to the conventional chemical process.

Key words: leather manufacture, clean-technology, protease, enzymatic properties