[Production and properties of the milk-clotting enzyme]

Milk-clotting enzyme from a strain of Mucor varians Pispek selected in a previous work was obtained by solid culture followed by water extraction. Moistened wheat bran (120% water on dry bases) proved to be a good medium for the production of the milk-clotting enzyme. The production may be related to growth and 4,000 U milk-clotting activity by g of wheat bran was achieved. The milk-clotting enzyme was easily extracted with water from the cultures and could be precipitated by salting out with ammonium sulfate or by mixing with ethanol, methanol or acetone. The crude enzyme is an acid protease having optimal activity at pH: 3.0. Like calf rennet, this crude enzyme from M. varians loses activity with heat treatment. The level of lipolytic activity of the crude enzyme is similar to some commercial preparations and neither an antibiotic nor an amylase activity was demonstrated in the crude extracts.