Abstract

The use of enzymes in the leather industry in the beamhouse area to partially replace sulfide, can reduce to almost 50% the H2S emission. In this enzyme treatment proteolysis needs to be controlled to prevent the extension of its activity to collagen. Collagen must keep its optimal conditions for the tannage process and to give high quality leather. In this sense it is necessary to characterize the enzyme from the physicochemical point of view and to study the morphological changes produced in bovine skin to control its action. An enzymatic pool of geophilic strain Trichophyton ajelloi cultured in solid media was characterized. Azocaseinolytic and keratinolytic activity was determined under different conditions. The enzymatic pool showed tolerance to high T°, optimal pH9 in both substrates, partial inhibition in concentrations 0.1M, 0.01M and 0.001 M from metallic salts (Ca Cl2, BaCl2, KCl, CuSO4), activation by NaCl, reducing agents as Na2SO3, Na2S, L-cystein hydrochloride monohydrate, thioglycolic acid and commercial anionic and non-ionic surfactants (SDS, Isográs AN, Triton, Baymol, Azymol). Inactivation exerted by PMSF showed a serine-protease as a component of the pool (MEROPS system). When the enzymatic pool was applied for 24-48 hours under optimal conditions on bovine skin pieces, a depilatory effect was observed. The changes in the bovine skin morphology were observed by SEM, after fixation in formaldehyde and dehydration with alcohol as part of a tentative protocol for bovine skin analysis by SEM (Scanning Electron Microscopy).