1 68 Tannic Acid Fermentation 



the amount of the enzyme is probably correlated, at least with 

 respect to Penicillium sp. 



Culture No. 1 shows a small decrease in tannic acid and a high 

 decrease in gallic acid. In culture No. 2 the loss of tannic acid 

 is greater than loss of gallic acid. The probable explanation is 

 that Penicillium sp. utilizes first the galhc acid and then transfor- 

 mation of the tannic acid occurs. In culture No. 1 the smaller 

 growth has been at the expense of tannic acid. It does not seem 

 possible to demonstrate that tannic acid is not directly utilized but 

 it seems probable that it must be converted into gallic acid. 



Influence of duration and extent of growth and comparison of organ- 

 isms. In order to determine the yield of gallic acid at different 

 intervals, and so to note the influence of growth and duration on 

 the fermentation, an experiment was made as follows: Solution 

 B was used and to it were added 7.5 grams of Merck's purified 

 tannic acid per 100 cc. of solution. The concentration of the 

 tannic acid was such that it came within the limits, as found by 

 Van Tieghem,28 most favorable for Penicillium glaucum. For the 

 investigation 50 cc. of the culture solution were placed in Erlenmeyer 

 flasks of 150 cc. capacity. The cultures were sterilized for fifteen 

 minutes at 5 pounds' pressure and then inoculated according to the 

 method described. The cultures were kept in an incubator at 31° 

 and, at intervals, as indicated, duplicate cultures were taken for 

 analyses. The mycelium was removed by filtering with suction 

 through the Gooch crucible, and it was then washed with warm 

 water to dissolve all adhering gallic acid. The solution was then 

 brought up to 500 cc. and analyzed according to the method of 

 Jean.29 The results of the experiment are given in Table III. 



In culture No. 8 the amount of gallic acid decrease was 0.126 

 gram and the tannic acid decrease only 0.069 gram, recalling the 

 case of No. 1, table II. Penicillium sp., it seems, therefore util- 

 izes the gallic acid first, and then the secretion of enzyme involves 

 th.e transformation of the tannic acid. In all of the succeeding 

 cultures the tannic acid decrease is greater than the increase of 

 gallic acid, and this is to be accounted for, again, not by a direct 

 utilization of tannic acid but by the fact that the tannic acid is 

 first converted into gallic acid; and the constant increase of the 



-' Loc. cit. 

 ■^^Loc. cit. 



