IMICROORGANISMS CONCERNED IN THE OXIDATION 

 OF SULFUR IN THE SOIL 



II. THIOBACILLUS TIIIOOXIDANS, A NEW SULFUR-OXIDIZING 

 ORGANISM ISOLATED FROM THE SOIL' 



SELMAN A. WAKSMAN and J. S. JOFFE 



Received for publication June 16, 1921 



By composting sulfur, rock phosphate and soil it was found 

 (McLean, 1918) that sulfur is rapidly oxidized to sulfuric acid; 

 the acid acts upon the tricalcium phosphate, converting it into 

 di- and mono-calcium salts. In the absence of a neutralizing 

 agent or, after this agent has all been used up, the sulfuric acid 

 formed, in the presence of an excess of sulfur, accumulates in the 

 medium. On inoculating such composts into proper culture 

 media, we finally succeeded in isolating a small bacterium which 

 is active in the oxidation of the sulfur. A detailed study of the 

 composting of sulfur, of the transformation of the tri-calcium 

 phosphate and of the methods used in the isolation of the organism 

 are found elsewhere (Lipraan, Waksman and Joffe, 1921); only 

 a brief review of the process of isolation is presented here. 



Method of isolation. The following media were originally used 

 for the isolation of the organism: 



Medium 1 : 



(NH,), S0« 2.00 gram 



KjHPO, 1.00 gram 



MgSO« 0.50 gram 



KCl 0.50 gram 



FeSO, 0.01 gram 



Sulfur 10.00 grams 



Ca, (P04)j 10.00 grams 



Distilled water 1000.00 cc. 



Medium S: Same as no. 1, but with 0.1 per cent glucose. 



Medium 3: Same as no. 1, but in place of 10 grams only 2.5 grams Caj(PO«)i ^ 

 per liter. 



'Paper No. 33 of the Technical series, New Jersey Agricultural Experiment 

 Stations, Department of Soil Chemistry and Bacteriology. 



239 



