NOVEL FUNGAL COLLAGENASE FROM ASPERGILLUS ORYZAE

The industrial processing of leather has a high environmental impact due to the heavy use of polluting chemicals in the tanning process. Microorganisms can be used in order to degrade natural fibers like fur, leather and cotton because they synthesized enzymes that can break chemical bonds in these materials. Some proteolytic enzymes, like collagenases, have a number of industrial applications in fur and leather industry and, moreover, are nontoxic and ecofriendly. This paper reports the purification and characterization of a fungal collagenase produced by an Aspergillus strain. Aspergillus oryzae Mi 156 and Aspergillus ochraceus Mi 153 were tested for their capacity to degrade native collagen. Enzymatic activity and protein content were determined using spectrophotometrical methods. The best results regarding collagenolytic activity were obtained for fungal strain Mi 156. The enzyme was separated by ammonium sulphate precipitation and analyzed for its optimum pH and temperature. The effect of some activators and inhibitors on the enzymatic activity was also tested. The results indicated 8 – 8.3 as optimum pH and 35 – 40 R C as optimum temperature. When using Zn 2+ as activator the collagenase activity was about 29 % higher, while for Co 2+ as inhibitor, the activity dropped down about 14 %.