GB860312A - Keratinolytic enzymes - Google Patents

Abstract

Keratinolytic enzymes are produced by cultivating a keratinase-producing strain of Aspergillus flavus, e.g. ATCC 13003 or Aspergillus niger, e.g. ATCC 13004, in an aqueous nutrient medium containing a source of protein rich in sulphur containing amino acids and disulphide bonds and inorganic salts. Suitable proteins are keratins, e.g. hair, feathers, wool, horn meal, hoof meal, horn-hoof meal and partially degraded wool, i.e. an alkali degradation product of wool soluble to the extent of 10% in water and containing 15.3% nitrogen, 4.1% sulphur, 7.0% moisture and 0.5% ash. Suitable inorganic salts are sodium chloride, magnesium sulphate, calcium chloride, ferrous sulphate, zinc sulphate, potassium acid phosphate and dibasic potassium phosphate. In the example, the culture medium is an aqueous solution of all the above specified salts plus partially degraded wool. The pH is 5 to 9 and especially 6.5 to 7.5. The enzyme is isolated from the clarified broth by (a) adsorption and (b) precipitation.