Chapter VI — 10^ — Enzymes, etc. 



Certain actinomycetes exhibit, for example, marked proteolytic 

 activity upon wool fabrics. The sterile culture filtrate of one organism 

 was found (141) to exert a marked effect not only upon protein de- 

 rived from soybeans, casein, peanut and corn, but also upon wool fiber, 

 to the extent of 5 to 85 per cent. 



Amylases.— A large number of actinomycetes are capable of bringing 

 about rapid hydrolysis of starch, either to the dextrin stage or directly 

 to maltose and glucose. These reactions are carried out by means of 

 active amylolytic enzymes. This phenomenon was first observed by 

 Beijerinck and Sames C^77^, and later confirmed and extended by 

 Krainsky, Waksman, Lieske, and others. 



The method of screening a large number of cultures consists in 

 streaking agar media containing starch as the source of carbon, and 

 allowing it to incubate. After 5, 10, 15 and 20 days, the surface of the 

 agar is covered with a solution of I-KI, and the degree of starch hydrol- 

 ysis measured by the width of the clear zone. It is thus possible not 

 only to establish that many species are capable of producing amylolytic 

 enzymes, but the active forms can be selected for further study. For- 

 mation of a zone of 1.0 to 1.5 cm. in 10 days is an index of excellent 

 amylase production. Inorganic sources of nitrogen, especially nitrates, 

 appear to be preferable to organic forms for the production of amylolytic 

 enzymes. 



Just as in the case of the proteolytic enzymes, the amylases of actino- 

 mycetes are able to withstand the effect of higher temperatures better 

 than are the cells of the organism producing these enzymes. Surovaya 

 (410) obtained a potent diastatic enzyme preparation from a culture of 

 an organism described as S. diastaticus. The culture was grown on a 

 potato medium for the production of the enzyme. The preparation was 

 designated as "superbiolase." It was active at 70° to 100°C. and had 

 an optimum pH at 6.6 to 6.7. The starch was converted first from the 

 insoluble into the soluble form and then to dextrin. Saccharification 

 of the dextrin proceeded much more slowly than starch liquefaction. 

 This points to the possible application of such enzyme preparations to 

 industrial processes where the sugar produced is not essential. 



Many species of actinomycetes are also able to attack dextrins, gly- 

 cogen, and inulin and to produce the corresponding enzymes. So far, 

 however, no attempt has been made to study these enzyme systems in 

 detail or to utilize them for any practical purposes. 



Invertase.— The wide distribution of invertase among the actino- 

 mycetes has been pointed out by Krainsky, Caminiti (61), and 

 Waksman. The ability of some species to utilize sucrose as a source 

 of carbon is dependent upon the property of the organisms to produce 

 this enzyme. 



Although many species of Streptomyces and Nocardia are able to 

 utilize sucrose, the production of invertase has not been established for 

 all forms. It has even been suggested that this property be utilized for 



