Optimization of Dehairing/Fiber Opening using Ammonium Chloride/Dispase by Response Surface Methodology

A great number of pollutants including sulfides, suspended solids, and ammonia nitrogen compounds are generated by dehairingand fiber opening with the traditional use of sodium sulfide, calcium hydroxide, and ammonium salt. In this work, ammoniumchloride (NH4Cl)/dispase system was used for the dehairing and fiber opening as an alternative of sodium sulfide/lime system tosimplify the beamhouse operations, as well as to ease environmental pollution. It was found that the removing effect of interfibrillar substance is highly related to the factors such as enzyme catalysis time, temperature and the salt usage. Therefore, the mathematical models of enzyme activity, protein content, polysaccharide content and hydroxyproline content were established by response surface methodology (RSM) with the enzyme catalysis time, temperature and the salt usage as independent variables. It was found that the dehairing/fiber opening effect is the best with 2 % NH4Cl (base onhide weight) at 32.5°C for 15h, and only 3.5 h is needed for dehairing. This work might provide a reference for green leather making with enzymes.