Process for lime and sulfide free unhairing of skins or hides using animal and/or plant enzymes

摘要

The present invention relates to a process for lime- and sulfide-free unhairing of skins/hides using animal and/or herbal (plant) enzymes. The process comprises presoaking the skins or hides in water for 2-6 hours, pasting an enzyme solution of animal or plant origin on the flesh or grain side of the skins/hides and leaving the solution on the skins/hides for 10-24 h at a temperature ranging from 10° C. to 60° C. The soaking liquor is removed and the hides/skins to a bath of water containing 1 to 15% of enzyme for unhairing, with or without intermittent shaking, while maintaining the pH of the bath liquor at 4.5-10.0 for 12-24 h at ambient temperature. The skins/hides are then unhaired for further processing. The total elimination of lime and sulfide in the unhairing process leads to reduced TDS (total dissolved solids), BOD (biological oxygen demand) and COD (chemical oxygen demand) in the effluent without affecting the collagen of the skin/hide or the grain pattern.