PROTEOLYTIC ACTIVITIES OF SOIL MICROORGANISMS 487 



As was already pointed out in another place (Waksman, 1917), 

 the amount of available carbohydrates has a decided influence 

 upon the metabolism of the organism and its power to accumulate 

 ammonia from the splitting of proteins. Where sugar or other 

 available carbohydrates are present, the organism will utilize 

 these as a source of energy and split off from the protein only as 

 much nitrogen as it needs for its metabolism; the quantity of 

 ammonia accumulated in the medium will therefore be small. 

 But, when available carbohydrates are absent, the organism 

 will attack the protein molecule, not so much for the nitrogen as 

 for the carbon part of it. The protein molecule decomposed 

 into its constituent groups will lose its carbon, while only a small 

 part of its nitrogen will be used up by the organism, because the 

 carbon requirement of the organism is much greater than its 

 nitrogen need, and therefore most of the nitrogen will be accumu- 

 lated in the medium as a waste product, in the foi-m of ammonia. 

 A full discussion on this subject will be found in the article pre- 

 viously cited (Waksman, 1917). Dory land (1916) has shown 

 that glucose has a detrimental effect upon ammonia production 

 by bacteria in the decomposition of proteins; he attempted to 

 explain this by the fact that the organisms consume some of the 

 ammonia liberated by them from the protein, thereby leaving 

 less ammonia in the soil or in the culture medium. Doryland 

 assumed that the ammonia is produced by the bacteria even in 

 the presence of glucose and is reconsumed by the organisms which 

 are able to multiply more readily and use the more available food, 

 although in another place Doryland himself states that "the 

 presence of dextrose sometimes may lessen the amount of casein 

 decomposed and amount of ammonia accumulated." 



To throw more light on the production of ammonia from 

 simpler compounds and thus perhaps indicate the possible 

 formation of ammonia from proteins, the following experiment 

 was started: Asparagine was added in quantities of 1, 5, 10, and 

 25 grams per liter of Czapek's solution, with the elimination of 

 the NaNOs. Each liter of medium was distributed in 100 cc. 

 portions in 200 cc. Erlenmeyer flasks, and these were sterihzed 

 as usual. All the 40 flasks, were inoculated with an approxi- 



