40 RAPER 



It was then known that the molds responsible for the desired hydrolytic 

 processes represented, in the main, strains of Aspergillus oryzae and closely 

 related species, and Takamine obtained patents covering processes for the 

 propagation of such molds and the recovery from them of preparations rich 

 in amylolytic enzymes. He subsequently established a factory in New Jersey 

 for the manufacture of diastatic and proteolytic enzymes of mold origin. 



Other microbiologists in other laboratories extended his investigations and 

 at the same time broadened their researches to include other microbial en- 

 zymes. Much has been accomplished, and today a great number and diver- 

 sity of products with varied properties derived from molds, yeasts, and 

 bacteria are commercially available. It is not possible to cover all these, 

 but I shall briefly discuss the more important products and their applica- 

 tions. 



Much attention has been directed toward the production of amylolytic 

 enzymes. Normally there are substantial outlets for these, and in periods of 

 national emergency such need is greatly increased because of the necessity 

 of conserving grain supplies, including the barley from which malt is de- 

 rived. Substantial progress toward the development of a mold-bran process 

 for the production of amylolytic enzymes was made during World War I and 

 in the years that followed, and during World War II a large mechanized 

 factory was constructed and operated. The product in this case is the enzyme- 

 rich dried bran upon which a selected strain of A. oryzae has been propa- 

 gated, and it is used by direct addition to grain mashes in lieu of malt. 

 Concentrated enzyme preparations can be produced as needed by aqueous 

 extraction and evaporation, and crystalline products can be obtained by 

 precipitation with ethyl alcohol. Of recent date, H. M. Tsuchiya and other 

 investigators at the Northern Regional Laboratory have developed a process 

 for the production of fungal amylase in submerged culture using selected 

 strains of A. niger. As with mold bran, the whole culture is used as a con- 

 verting agent, this substituting either largely or entirely for malt. In addi- 

 tion to their somewhat intermittent use in the alcoholic fermentations (de- 

 pending largely upon economic considerations), microbial amylases find im- 

 portant uses in other industries. Those obtained from molds find a limited 

 outlet in certain pharmaceuticals and substantially larger uses in the food 

 and baking industries, the products being more or less tailor-made for par- 

 ticular applications. Amylolytic enzymes are likewise produced by bacteria, 

 and the amylase of Bacillus subtilis is now manufactured on a large scale. 

 This can be produced by growing the bacillus on bran, as a surface pellicle 

 on the surface of shallow layers of a liquid substrate, or in submerged culture 

 with aeration and agitation. It is of special value in the textile industry since 

 it retains its activity at 95 °C.; because of this property it has permitted 

 revolutionary changes in the desizing operations of the textile industry. 



Proteolytic enzymes can be produced by molds of the same species, As per- 



