200 Nutrition and Tannase Production 



creased by increasing the concentration of the gallic acid. In 

 the experiment, the results of which are given in table X, the usual 

 methods were followed. Erlenmeyer flasks of 250 cc. capacity 

 were used and 100 cc. of the nutrient solution. For determining 

 the tannase activity of the various cultures 0.05 gram of the dried 

 mycelium was added to 50 cc. of 1 per cent tannic acid solution 

 and the solutions incubated for forty-eight and eighty hours respec- 

 tively at a temperature of 30°. The culture solutions were tested 

 for their tannase content by precipitating any enzyme present with 

 alcohol and collecting on a filter any precipitate. The test for the 

 enzyme was made as before. Incubation was made at a tempera- 

 ture of 30° for ninety hours. The results in table X are the aver- 

 ages of two cultures. 



TABLE X. 



Aspergillus niger. 

 Effect of concentration of gallic acid on the production of tannase. Average 

 period of incubation for mycelial powder 64 hours and for enzyme excreted 

 90 hours. 



COMPOSITION OF NUTRIENT 

 SOLUTION 



WEIGHT OP 



FUNGUS. AV. Op 



2 CULTURES 



INCREASE IN GALLIC ACID 



Mycelium 

 Av. of 2 



Enzyme ex- 

 creted. Av. of 2 



Total increase 

 in gallic acid 



Solution B 

 cent sugar 

 cent gallic 



Solution B 

 cent sugar 

 cent gallic 



Solution B 

 cent sugar 

 cent gallic 



Solution B 

 cent sugar 

 cent gallic 



-I- 10 per 

 + 0.1 per 



acid 



+ 10 per 

 + 0.5 per 

 acid .... 

 + 10 per 

 + 1.0 per 



acid 



+ 10 per 

 + 1.5 per 

 acid .... 



0.240 



0.442 



0.324 



0.280 



0.024 



0.045 



0.046 



0.024 



0.045 



0.046 



An examination of the above table reveals the fact that the 

 enzyme tannase is produced when the concentration of gallic acid 

 is 0.5 per cent in the presence of 10 per cent sugar. At a concen- 

 tration of 1.0 per cent gallic acid in the presence of 10 per cent 

 sugar the amount of tannase produced is double that produced 

 when only 0.5 per cent galhc acid is present. In the presence of 



