Highly clean and efficient enzymatic dehairing in green solvents

Abstract

Enzymatic dehairing in aqueous medium is in demand over lime-sulphide based conventional method of leather making due to the environmental concerns. However, the use of water not only depletes precious natural resource but also leads to incomplete hair removal. Here, we report the enzyme-only dehairing of sheepskins in chosen green solvents. The enzyme showed better activity in the presence of heptane and propylene glycol than in aqueous medium. This was substantiated with a limited computational study involving protease-solvent interface. Further, it is demonstrated that the solvent-enzyme mixture removed hair more efficiently without any sulphide and lime than aqueous enzyme-lime-sulphide system and produced leathers with properties similar to conventional method. Also, a complete elimination of sulphide emission and reduction in the pollution loads such as lime and total dissolved solids is observed. Recycling studies demonstrate that it is industrially feasible to replace water with green solvents for enzymatic dehairing process. The findings have great implications for not only leather industry but also other industries where usage of enzyme is contemplated.