170 



Transformation of Nitr 



ogen 



63 



57 



— NHj-N, Bac. cereus 

 and Pseud, fluorescens 



' / NH^-N, Bac. cereus 



t / / and Pseud, fluorescens 



1 2 



15 



4 6 9 



Days 



Fig. 72. Course of accumulation of amino- and ammonia-nitrogen from casein 

 6y Bacilhis cereus and Pseudomonas fltiorescens (from Waksman and Lomanitz). 



A large number of microorganisms are able to use hippuric acid 

 as a source of carbon and nitrogen. The acid is usually first hydro- 

 lyzed by an enzyme produced by these organisms: 



CeHs CONHCH2 COOH + II2O = Cells COOII 



Hippuric acid Benzoic acid 



+ NH2CH2COOH 



Giycocoll 



Urea is hydrolyzed, with the formation of ammonia, by a large 

 number of soil microorganisms as well as by specific groups of bac- 

 teria, which utilize the energy liberated in the process: 



C0< + 2H.0 = (NIl4).C0a = COs + 2NH3 + HoO 



\NH2 



