Feb. 15, 1921 



Amylase of Rhizopus tritici 



767 



loss in reducing power. These results are in accord with those of Dox 

 (9), who found that mycelium may be kept almost indefinitely without 

 losing its activity. 



Table III. — Amount of reducing sugars produced by the same samples of mycelium xised 



at different times 



INFLUENCE OF DIFFERENT TEMPERATURES ON THE AMYLOCLASTIC 

 ACTIVITY OF THE MYCELIUM 



Although it was shown by Table III that mycelium may be stored at 

 27.5 C. for a number of months without materially affecting the activity 

 of the enzym, it can not be concluded that it can be kept unimpaired at 

 any temperature. As a matter of fact, the following results show that 

 the hydrolytic power of the enzym is somewhat impaired when held for 

 a time at a high temperature. 



The mycelium for these experiments was produced in six 2-liter flasks 

 containing about 750 cc. of sweet potato bouillon. At the end of the 

 growth period the mycelium was made into one composite sample and 

 held at a temperature of 9 C. for 18 hours. A sample was then removed 

 and its original hydrolytic power was determined. The remainder was 

 divided into three lots, one being stored at 9 , one at 35 , and one at 6o°. 



To determine the original hydrolytic power of the mycelium two 

 0.25-gm. lots were weighed out and ground in fine quartz sand. To one 

 flask containing enzym powder were added 100 cc. of a 0.5 per cent 

 starch paste solution and to the other 100 cc. of sterile distilled water. 

 After the addition of toluol as an antiseptic both were digested for 18 

 hours at 40 C. In the former 2.2 mgm. and in the latter 33.46 mgm. of 

 reducing sugars were found in 10 cc. of solution, or a total of 22 mgm. 

 and 334.6 mgm. in 100 cc, respectively. These figures will serve as a 

 basis for comparison of future tests of the same lot of mycelium stored 

 at different temperatures. (Table IV.) 



Table IV. — Amount of starch hydrolized by mycelium stored at different temperatures 



for a given length of time 



[Expressed in milligrams per 10 ec. of solution] 



