SE304072B - - Google Patents

Abstract

In a process for softening, dehairing and bating skins and hides, they are subjected, e.g. at a pH between 5 and 10, to the action of at least one proteolytic enzyme and are also treated, before during or after said enzyme action, with hdrazine, e.g. hydrazine hydrate, or a hydrazonium salt, e.g. hydrazonium sulphate. Enzymes derived from micro-organisms, such as fungal proteases from Aspergillus parasiticus and Aspergillus flavas or bacterial proteases from Bacillus subtilis, are suitable. Enzymes derived from animals, such as pancreatic trypsin (pancreas tryptase) may be used. In Example 7, protease from Bacillus subtilis and pancreas tryptase are used for dehairing softened ox hides. In Example 13, pancreas tryptase and protease from 'Aspergillus flavus are used for bating alkaline-limed goat skins. The proteolytic enzyme may be used in the presence of carbohydrases (Example 4), or in the presence of one or more than one of the following salts: ammonium sulphate, sodium bisulphite, sodium chloride and soda. In Example 2, phthalimide is present during dehairing and softening of ox hides. In dehairing skins or hides, they may be soaked in an aqueous solution of hydrazine or a hydrazonium salt, and the proteolytic enzyme may then be added without further addition of water. In softening and dehairing skins or hides, between 0.25 and 1.25%, of hydrazine or hydrazonium salt may be used, computed on the weight of the skins or hides. In bating skins or hides, between 0.025 and 1.0% of hydrazine or hydrazonium salt may be used.