MOLD ENZYME PREPARATIONS 239 



cooled. Ample amounts of moist (to prevent the drying of bran) 

 air to furnish oxygen for the mold and to cool the bran are essential. 

 In about 48 hours the development of the mold, and of the enzyme, 

 is at a maximum. The molding material may now be dried or the 

 crude amylase preparation extracted with water. A precipitate of 

 the crude enzyme may be obtained by the addition of aqueous ex- 

 tract to alcohol to produce a 70 per cent alcohol concentration. The 

 alcohol precipitate, dried in vacuo at 30° C. and powdered, presents 

 a white to a whitish yellow appearance. Aqueous solutions of 

 amylase, if not to be used for medicinal purposes, should be pre- 

 served with chemical antiseptics such as chloroform, toluene, thymol, 

 phenol. Addition of sodium chloride to produce a 20 per cent con- 

 centration has also been recommended. In the Orient, amylase prep- 

 arations of strains of A. flavus-Oryzae group have been used in much 

 the way we use malt in the occidental countries. The use of this 

 mold enzyme preparation was introduced in the United States by 

 Takamine. At present commercial mold amylase preparations may 

 be obtained under various trade names. It should be noted that 

 most of these preparations are not pure amylase but actually mix- 

 tures of various enzymes and thus may display proteolytic activity 

 in addition to their amylolytic property. 



A more recent development has been the growing of the desired 

 mold on bran placed in rotating drums, much like those used in 

 drying germinated barley (in the preparation of malt). The mois- 

 tened bran, after inoculation, is tumbled in the rotating drums until 

 the mycelial growth and amylase contents are at a maximum. 



The most recent method advocated for the production of fungus 

 amylases is that described by Fulmer and his associates.^^ They 

 employ aluminum pots or pans with holes drilled in the bottoms. 

 The pots are filled with wheat bran moistened with 0.3 A'' hydro- 

 chloric acid and inoculated with sporulated cultures of the mold. 

 The initial temperature of the mash is 30° C, but with the rapid 

 growth of the mold it rises to 37° to 40° C. in about 8 hours. Air is 

 then passed through the mash to maintain a temperature below 45° C. 

 After 12 to 24 hours of aeration the contents of the pots are removed 

 and dried. These investigators found that while certain strains of 

 Rhizopus gave good yields, strains of A. flavus-Oryzae group gave 

 not only good yields but also the most consistent results. 



Amylase is used in the preparation of sizes and adhesives, textile 

 desizing, clarification of certain fruit juices, and the like. 



Invertase, an enzyme which hydrolyzes sucrose to invert sugar, 

 i.e., glucose and levulose, can also be prepared from certain molds. 

 It is used in the confectionery and syrup industry. Protease, a mix- 



