Value addition of fish waste in the leather industry for dehairing

This study explores the feasibility of utilizing enzymes derived from fish wastes as a low cost depilatory agent. These enzymes are eco-friendly alternative to the conventional lime-sulphide dehairing process. The crude enzyme extract was partially purified with a yield of 60% (Specific protease activity is 4683 U/mg of protein). Optimum pH and temperature for enhanced protease activity of partially purified protease were 8.0 and 30 degrees C, respectively. The partially purified protease was evaluated for its dehairing efficiency of goat skins. It was observed that the release of proteoglycans and saccharides in the spent liquor after dehairing was 4300 mu g/mL and 28 mu g/mL, respectively. In the wet blue stage, the enzyme treated leathers exhibited shrinkage temperature of about 110 +/- 2 degrees C, which was found to be on par with that of control leathers. The morphological features were examined through histological and scanning electron microscopic analysis, which reveals a complete removal of hair in the skin matrix. The organoleptic properties and visual assessment of crust leathers were carried out. The physical strength of the crust leathers developed from the enzyme treatment has met the UNIDO norms. Moreover, a significant reduction in the pollution loads was observed in terms of total solids (81%), biological oxygen demand (90%), and chemical oxygen demand (88%) in the dehairing waste stream. (C) 2016 Elsevier Ltd. All rights reserved.