igo 



Nutrition and Tannase Production 



gram of the dried powder was added to a flask containing the tan- 

 nic acid solution. Each flask contained 75 cc. of an approximately 

 0.9 per cent solution to which was added, as an antiseptic, 1 cc. 

 of toluene. The results after one week's incubation at 34° are 

 given in table I. The solution contained at the beginning of incu- 

 bation 0.555 gram tannic acid and 0.327 gram gallic acid. 



TABLE I. 



Effect of concentration of tannic acid on production of enzyme tannase; using 

 nutrient solution B -\- 10 per cent sugar + tannic acid. Period of incuba- 



* The actual concentration of each culture was approximately only two-thirds of the fieures 

 given, the other one-third consisting of gallic acid. 



It is evident from the preceding table that there is a regulatory- 

 formation of the enzyme. There is a progressive increase in the 

 amount of tannase with increase of tannic acid in the culture solu- 

 tion. It is noteworthy that no tannase was produced when growth 

 took place in a nutrient solution which lacked tannic acid. It is 

 somewhat remarkable that the formation of enzjone could be 

 stimulated by 0.1 per cent of tannic acid (actually about 0.066 per 

 cent) when there was present at the same time cane sugar in an 

 amount more than one hundred times as great as the tannic acid. 

 The stimulation by this small amount of tannic acid is even more 

 surprising when previous experiments^^ are recalled in which the 

 gallic acid formed from the tannic acid was protected by the cane 

 sugar, no determinable amount of the gallic acid being assimilated. 



^' L. Knudson: loc. cit. 



