Environmentally friendly hide unhairing: Enzymatic-oxidative unhairing as an alternative to use of lime and sodium sulfide

Various studies have been conducted to develop technologies that minimize the environmental concerns associated with the leather industry. The use of enzymes and oxidizing products during the unhairing step reduces pollution by tanneries as well as process time. In this study, were used an enzymatic extract produced by a strain of Bacillus subtilis - BLBc 11 - and hydrogen peroxide to conduct enzymatic-oxidative unhairing as an alternative to the conventional process (lime and sodium sulfide). Tests for enzymatic-oxidative unhairing were performed by applying crude enzymatic extract at concentrations of 100 U g−1 and 300 U g−1 of hide and hydrogen peroxide at concentrations of 4% and 8%. Tests were conducted comparing the proposed unhairing method, the conventional unhairing and purely enzymatic unhairing, performed with crud enzymatic extract produced by strain BLBc 11. The results showed that the proposed enzymatic-oxidative unhairing method can be used as an alternative to lime and sodium sulfide.