212 PRINCIPLES OF SOIL MICROBIOLOGY 



and hydrolizing uric acid into ammonium carbonate and carbon dioxide. 

 The optimum temperature was 29° to 42° and at 50° the organism was 

 killed. Bad. vulgare can also decompose uric acid. 22 



Liebert 23 isolated from the soil Bad. acidi urici, an incompletely 

 described species, 5 by 0.7/x in size, spore forming and anaerobic. It 

 decomposed uric acid, under anaerobic conditions, with the formation 

 of C0 2 , ammonia and acetic acid. 



The aerobic decomposition of uric acid is also carried out by Bad. fluorescens 

 liquefaciens and non-liquefaciens, by Bad. calco-aceticum and Bad. pyocyaneum 

 in neutral and acid media, and by Bad. odoratum in alkaline media. These 

 transform uric acid into C0 2 and NH 3 with the intermediate production of allan- 

 toin, urea, and oxalic acid. On a medium consisting of 2000 parts of water, 

 6 parts uric acid, 1 part K 2 HP0 4 , various organisms (aerobic and anaerobic) capa- 

 ble of utilizing uric acid both as a source of nitrogen and carbon can be isolated 

 from the soil. Bad. stutzeri and Bad. pyocyaneum were found capable of utiliz- 

 ing uric acid as a source of carbon for denitrification. Various Radiobacter 

 strains are able to decompose uric acid with the formation of ammonia. 21 



By using a medium consisting of five grams NaCl, 0.2 gram MgSO,}, 0.1 gram 

 CaCl 2 , 1.0 gram K 2 HP0 4 , 30.0 grams of glycerol and 0.2 gram of uric acid in 

 1000 cc. of distilled water, an organism, Aerobader aerogenes, capable of decom- 

 posing uric acid was isolated. 25 In addition to bacteria, certain fungi and yeasts 

 also decompose uric acid. 26 



Hippuric acid abundantly produced by herbivorous animals is trans- 

 formed by bacteria into glycocoll and benzoic acid. 27 It can be used by 

 a large number of bacteria both as a source of nitrogen and carbon, 

 with the formation of ammonia and carbon dioxide. Among the bacteria 

 described by the earlier investigators, we may mention: Microc. ureae, 

 Microc. pyogenes, Bad. prodigiosum, 2 * Bad. erythrogenes, Bad freu- 

 denreichii, Bac. vulgatus, Bac. mesentericus, etc. A medium con- 

 taining 1 per cent sodium hippurate, 0.2 per cent K 2 HP0 4 and 0.1 per 



22 Nawiasky, P. Uber die Umsetzung von Aminosauren durch Bac. proteus 

 vulgaris. Arch. Hyg. 66: 241. 1908. 



23 Liebert, F. The decomposition of uric acid by bacteria. Akad. Weten- 

 schap. Amsterdam. May 6, p. 61. 1909. 



24 Bierema, 1909 (p. 187). 



28 Morris, J. L., and Ecker, E. E. Destruction of uric acid by bacteria and 

 molds. Jour. Inf. Dis. 34: 592-598. 1924. 



26 Kossowicz, A. Die Zersetzung von Harnstoff, Harnsiiure, Hippursaure und 

 Glykokoll durch Schimmelpilze. Ztschr. Garungsphysiol. 1: 60-62. 1912. 



27 Van Tieghem. Recherches sur la fermentation de Puree et de l'acide hip- 

 purique. Compt. Rend. Acad. Sci. 58: 210-264. 1S64. 



28 Crisafulli, G. La reazione rossa del legno di pino per la ricerca dello indolo 

 nelle culture in brodo dei microorganismi. Roma. 1905. 



