Utilization of vegetable tannins for stabilization of collagen fibers by using supported process enzyme

Abstract

Tanning is the process of treating animal skins or hides to produce leather, which is more durable and less susceptible to decomposition. The leather industry has been pushed to develop tanning systems that utilize natural products due to environmental concerns. Vegetable tanning is one of the oldest methods, but its usage is limited due to the high organic load in the effluent generated. This load is difficult to degrade and results in high biological and chemical oxygen demand. This study aimed to develop an eco-friendly tanning process for protein fibers using proteolytic enzymes. The goal was to improve the exhaustion of vegetable tannins by increasing their uptake during the tanning process. The optimized experimental process, which involved enzymatic treatment of protein fibers, resulted in an exhaustion of 97% compared to 83% in conventional vegetable tanning processes. Enzyme treatment before tanning also led to a slight improvement in hydrothermal stability, as well as slightly better physical properties of the resulting leathers compared to conventionally tanned leathers. The enzymatic process has the added benefit of reducing total solids (TS) and chemical oxygen demand (COD) loads in the identified streams by 80% and 33%, respectively.