64 BACTERIAL FERMENTATIONS 



not been obtained only by the study of organisms isolated 

 from highly selective enrichment media. Several investi- 

 gations have been carried out on anaerobic bacteria obtained 

 by direct isolation from soil, spoiled foods, infected wounds, 

 and similar sources. Species that apparently derive most 

 of their energy from the fermentation of single amino acids 

 include CI. tetania 6 ' 17 CI. saccharobutyricum, 18 Micrococ- 

 cus aerogenes, 19 and Fusobacterium nucleatum, 20 which use 

 glutamate, histidine and serine, sometimes threonine and 

 cysteine, and occasionally aspartate, lysine, and tyrosine. 

 Other species in this group are M. anaerobius and M. vari- 

 abilis, 21 which like D. glycinophilus appear to be restricted 

 to the utilization of glycine. In addition, a number of 

 bacteria, both obligate and facultative anaerobes, are able 

 to decompose some or all of the amino acids which readily 

 undergo a non-oxidative deamination, namely serine, cys- 

 teine, threonine, and arginine. These bacteria include CI. 

 welchii, 22 CI. sporogenes, 23 CI. botulinum, 24 E. coli 25 - 26 

 Proteus vulgaris, 27 ' 28 P. morgani, 29 and an anaerobic coccus 

 isolated from the rumen of the sheep. 30 A conversion of 

 lysine to acetate, butyrate, and ammonia by CI. sticklandii 

 has been reported by Stadtman, 31 but this process alone 

 does not support growth. 



Chemistry of the Fermentations of 

 Nitrogen Compounds 



Fermentations of Histidine and Glutamate by Clos- 

 tridium tetanomorphum. Clostridium tetanomorphum 

 ferments histidine and glutamate with great facility. In 

 view of the evidence that the decomposition of histidine 

 goes by way of glutamate or glutamate derivatives in both 

 aerobic bacteria 32 and mammalian liver 33 it seemed desir- 

 able to find out whether the same or similar reactions are 

 utilized by anaerobic bacteria. 



