A One-Bath Strategy Replace of Conventional Beamhouse on Dispase from Bacillus Subtilis for Eco-Sustainable Leather Processing

Abstract

A reproducible dispse produced by Bacillus subtilis was used for one-bath strategy, i. e. dehairing, splitting collagen fibers and bating in same reactor with same reagents, replacing the conventional lime/alkali system with multiple pollution and cumbersome operations. The types and contents enzymes in dispase were characterized using ion mobility spectrometry (IMS). The effects of dehairing and splitting collagen fibers were investigated, and the physical and thermal properties and aggregate structure of crust leather from the one-bath strategy using alkali pre-expanded cattle hide were evaluated, and compared with the conventional ones. As a result, one-bath strategy using alkali pre-expanded cattle hide has good effects on dehairing (only needing 6 h) and splitting fibers (only needing 24 h) owing to dispase including neutral metalloproteinase, alpha-amylase, peptidase, protease, among others, and the physical properties of crust leather are better than the conventional ones, while the pollution loads are greatly decreased, especially water consumption decreased by nearly 80%. By employing one-bath strategy using NaOH pre-expanded cattle hide, rapidly hydrolyzes the proteoglycans and impure protein in cattle hides, while the collagen hydrolysis is very little. Besides, collagen fibrils dispersion, grain smoothness, the fluffy effect of collagen fibers and the physical properties of crust leather from one-bath strategy using NaOH pre-expanded cattle hide are the best, with hydrothermal shrinkage temperature comparable to that of conventional process. This work might provide a reference for simplifying the unit operations of conventional beamhouse, reducing the environmental pollution and developing of high-quality eco-leather.

Keywords: Beamhouse, Cattle hide, Bacillus subtilis, Leather making