Skin and Hide

Enzymes in the Tannery. The processing of skins and hides for leather (qv) has been based on enzymes ever since 1908 when Otto Rn hm patented the first standardized bate based on pancreatic enzymes (78). Leather chemistry research helped to improve understanding of the bating process, and at the same time spurred on developments to improve leather processing (79). 

Skin is unstable to varying environmental conditions and deteriorates readily under humid conditions or through biological activity, or both. Basically, the decay of much ancient skin and hide results from hydrolysis, that is, the reaction of the protein fibers in the skin with water in extreme cases, the hydrolysis of skin and hide may cause their total dissolution, and quite often, under humid and hot environmental conditions, nothing remains to indicate that skin or hide was once there. 

Strontium sulfide (SrS) smells like rotten eggs. It is used as a depilatory to remove hair from skin and hides. 

Proteinases in the Leather Industiy. Protease enzymes are used in the processing of skins and hides into leather, in particular for the removal of hair and wool, and for increasing the pliability (called bating) of leather. 

Aside from softening, a smaller amount of oils and fats as detergents are also used in preliminary cleaning of the raw skins and hides to suspend lime particles, buffer the alkaline solution that removes the epidermis and hair, and suspend these materials when they come off to remove grease to tan certain types of leather and to control the penetration of dyes. 

The oldest method of treating skin and hide for the purpose of preservation in a flexible state, which consisted in kneading with fatty substances, is of... 

Apart from skins and hides there are other products of the slaughter-house, such as horn, blood, hair and bristles, waste wool and the like, from which valuable chemicals such as cyanide are produced. Glue, too, is made from the chippings of hides, horns and hoofs, which are washed in lime-water, boiled, skimmed, strained, evaporated, cooled in moulds, cut into convenient pieces and dried on nets. The processes axe nowadays supervised by trained chemists. 

In the leather industry as cleaners for degreasing skins and hides auxiliaries in finishing, impregnating, and dyeing... 

Monsheimer, R., Pfleiderer, E. Method for preparirrg terrable pelts from animal skins and hides. US Patent 3966551, 1976. 

The earliest practical uses of papain were medicinal, e.g., in the treatment of dyspepsia and intestinal worms (86). Today most of the papain is consumed by various industries. Thus, it is used commercially for tenderizing meat, in the textile industry to prevent wool shrinkage, in the brewing industry to prevent oxidation and chill hazes in beer, in the tanning industry to bate skins and hides, and..in the manufacture of chewing gum. It is difficult to estimate the world consumption however, the United States alone imports about 500,000 pounds of crude papain annually (161). 

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