120 



V. H. YOUNG 



the preparation from the 0.4% cultures although somewhat 

 more than this is not proportionately so. The numerical data 

 for this experiment are presented below. The period of diges- 

 tion was three hours. 



It seemed desirable to repeat the above experiment using 

 greater concentrations of inulin and thus to provide greater 

 actual differences in the amount of inulin present per unit of 

 culture medium. The last experiment was, therefore, repeated 

 using cultures containing 1%, 1.5% and 2% of inulin as the sole 

 source of carbon. The two higher concentrations apparently 



TABLE 5 



Showing the effect of various concentrations of inulin as the sole source of carbon 



on inulase formation 



FUNGAL PREPARATIONS FROM CULTURES USING SOURCKS 

 OF CARBON LISTED BHLOW 



Inulin cultures (0.1%) 

 Inulin cultures (0.2%) 

 Inulin cultures (0.4%) 



PERCENT.VGE OFHYDROL- 

 YSIS OF INULIN BY 

 EQUAL UNITS OF FUN- 

 GAL ENZYME PREPA- 

 RATIONS 



per cent 



14.21 

 14.34 

 16.34 



provide more carbohydrate than can be used in the ordinary hfe 

 cycle of Aspergillus under the conditions of the experiment, since 

 large amounts of carbohydrate remain unused when the sporula- 

 tion period begins. The results of this experiment are surpris- 

 ingly uniform. The amount of inulin hydrolysis for equal 

 amounts of treated mycelium does not vary beyond the limits of 

 experimental error. 



Apparently in neither of these last described experiments is 

 the lowest concentration of inulin capable of stimulating inulase 

 formation reached although a decrease in formation begins to be 

 apparent when only 0.2% of inulin is present in the culture 

 medium. Conversely, no increase in inulase production for the 

 higher concentrations of inulin was observed. In connection 

 with some later results, further light on the lower limits of stimu- 

 lation will appear. 



