Cohesive system for enzymatic unhairing and fibre opening: an architecture towards eco-benign pretanning operation

Pretanning operation is always a challenging task in leather processes due to high generation of solid waste. Cleaner leather processing is a new avenue to exterminate the existing pollution complications. Enzymes are the best alternate to conventional chemicals in the context of cleaner leather processing. In the current investigation, pretanning processes are carried out with enzymes. Protease is used for unhairing and amylase is used to remove inter-fibrillary materials by treating with skin/hide matrix. Protease and amylase are suitably formulated (fibrozyme) and applied as a single system to substitute conventional liming/reliming processes. Fibrozyme with a concentration of 3.5% is optimized by drum method. Unhairing efficiency, extent of fibre opening through pore size evaluation, pollution load, morphology features evaluated through staining and SEM (Scanning Electron Microscope), physical strength characteristics, organoleptic properties and visual assessment of crust leathers are assessed. Unhairing efficiency of fibrozyme has matched with conventional liming system in terms of hair removal and general appearances. Shrinkage temperature of about 112 °C was observed in enzyme treated wet blue leathers. The physical strength of the crust leathers has met the UNIDO norms. Scanning electron microscopy study substantiates no distortion of fibres. The fibres are compact and uniformly opened up as well as distributed in enzymatic process. In single step enzyme process, there is reduction in pollution load. The study implies the role of enzyme in tanning industry and gives a new bioresource avenue to the existing cleaner processing systems.