116 V. H. YOUNG 



b. Effect of various carbohydrates as the sole source of carbon on 



inulase formation 



As seen from the review of the literature numerous workers 

 have tested the effects of various carbohydrates on the formation 

 of carbohydrate-sphtting enzymes. But few workers have 

 studied inulase from this point of view. The results of Dox 

 (1910) and Boselli (1911) in their studies of inulase are so dia- 

 metrically opposed that it seemed desirable to perform experi- 

 ments along a similar line. The first experiment performed was a 

 test of the effects of inulin, soluble starch, and sucrose on the pro- 

 duction of inulase in Aspergillus niger, when present in the culture 



TABLE 1 

 Showing the amount of inulase present at different times in the mycelium of 



Aspergillus niger* 



* All data in this and succeeding fables represent the amount of hydrolysis 

 less hydrolysis of controls. 



medium to the extent of 1%. The fungal extract was pre- 

 pared by extracting the prepared mycelium with 400 cc. of water 

 per gram of dehydrated mycelium. Equal amounts of the fun- 

 gal extract and of a 2% inulin solution were mixed giving a 

 solution containing 1% of inulin. This experiment was run for 

 twenty-four hours. 



The results of this experiment show very clearly that, in the 

 presence of inulin, Aspergillus produces a greater amount of 

 inulase than in the presence of equal amounts of sucrose or soluble 

 starch. From later experiments it will appear that the amount 

 of hydrolysis brought about by the fungal extracts of inulin and 

 starch cultures is rather low, and since these cultures ran some 

 ten hours beyond the time of full sporulation, it is believed 

 that some of the enzyme may have already been lost. The 



