FERMENTATIONS OF NITROGENOUS COMPOUNDS M 



several such compounds. A list of these species and the 

 substrates used for their isolation are given in Table 1. 



As has already been mentioned, glutamate is readily 

 fermented by Clostridia which are abundant and widely dis- 

 tributed in soils. 7 All of the glutamate-fermenting strains 

 we have isolated belong to one of two closely related species 



TABLE 1 



Some Amino Acid-, Purine-, or Pyrimidine-Fermenting Bacteria 

 Isolated by the Enrichment Culture Method 



which have been known for a long time, namely CI. coch- 

 learium and CI. tetanomorphum. The latter species has 

 been isolated also by enrichment with histidine. 8 Besides 

 decomposing glutamate and histidine, CI. tetanomorphum 

 is also known to ferment cysteine, serine, aspartate, and 

 tyrosine, 9 but the efficacy of these compounds as enrichment 

 substrates has not been tested. 



Enrichment with glycine 10 has given cultures in which 

 a non-motile coccus Diplococcus glycinophilus is the pre- 

 dominant organism. This species is highly specialized with 

 respect to its energy source since it appears to be limited 

 to the use of glycine and some simple peptides containing 

 glycine; it is unable to attack a variety of other amino acids 



