Surfactant-free beamhouse technology of leather manufacturing: Removing constraints for the breakdown of natural fats catalyzed by lipase

Abstract

As one of the pivotal processes in leather manufacturing, degreasing is especially substantial for fatty skins. Surfactant was the pollution of increasing concern in degreasing process due to the large amount of degreasing agents used in conventional degreasing process. In this study, we developed a surfactant-free beamhouse processing technology by removing the hydrolysis products of grease catalyzed by lipase. Fat hydrolyzation and fatty acid and salt dissolving rate were improved by controlling the beamhouse process, which can help with the effective removal of fats. The fundamental characteristics of this technology were the same even at room temperature. The degreasing rate was up to 90%, and the residual oil of bated pelts can be decreased to 3.33% or lower without any adverse effects on the organoleptic and mechanical properties of the resultant leather. The total volume of the wastewater, chemical oxygen demand in the spent floats, and amount of surfactant were reduced by 28.0%, 26.9%, and 100%, respectively, aside from the 3.78 × 105 kJ energy saving per ton of the wet-salted skins processed. The developed technology is beneficial for the treatment of the sewage by avoiding the use of surfactant in the beamhouse processing of leather making.