Hydrolysis of used leather and application of hydrolysates

Abstract

The leather industry generates a significant amount of various wastes, and their utilisation is a serious task for researchers. Ways to reuse or decontaminate such waste are being developed intensively. Unfortunately, the reuse of finished leather, which eventually becomes waste, is almost unexplored. The present research is designed to evaluate the potential of finished leather hydrolysis to obtain protein hydrolysates suitable for reuse in leather processing and to establish factors that influence leather quality during such an application. Enzyme preparation Vilzim PRO Conc was characterised as a potential agent for such hydrolysis. The addition of 3–4% Vilzim PRO Conc is appropriate for the enzymatic stage of the hydrolysis process. It was established that after alkaline­enzymatic hydrolysis of used leather powder the obtained hydrolysates are complicated systems containing proteins, chromium compounds, dyes, fatliquoring materials, etc. Hydrolysates could be used for the dyeing of chromed leather. The method of preparation for dyeing and dyeing of wet­blue leather with the use of hydrolysate influences the depth of dye penetration and the quality of finished leather. It was established that the neutralisation process is not necessary before such dyeing. Also, an increased amount of formic acid is necessary to improve the bonding of fatliquors with dermal tissue after treatment with hydrolysate.

Keywords

• exploited leather
• hydrolysis
• enzyme preparation
• collagen
• dyeing