MICROORGANISMS CONCERNED IN THE OXIDA- 

 TION or SULFUR IN THE SOIL 



V. BACTERIA OXIDIZING SULFUR UNDER ACID AND ALKALINE 



CONDITIONS' 



SELMAN A. WAIiSMAN 



Received for publication April 4, 1922 



A detailed description of media and methods of isolation of 

 sulfur bacteria concerned in the oxidation of yulfur in the soil 

 has been given in the previous two papers of this series (Waks- 

 man, 1922 a, 1922 b). 



The work reported in this paper is limited to two liquid (nos. 

 8 and 6) and two solid media (nos. 9 and 10). iMedium 8 

 consists of 5 grams Na^SoOs, 0.1 gram NH4CI, 0.1 gram MgCU, 

 0.2 gram NajHPOi (or K2HPO4), 1 gram NaHCO, and 10 

 grams CaCOs or 0.25 gram CaCh dissolved in 1000 cc. of tap 

 water. This is only a shght modification of the original Bei- 

 jerinck (1904) medium. Medium 9 is the same as 8, but with 

 2 per cent of agar added. These media are sterilized, at 15 

 pounds pressure, for fifteen minutes; the thiosulfate and car- 

 bonate are steriUzed, in the case of the liquid media, separately, 

 then added by means of sterile pipettes. The initial reaction of 

 these media is about pH =8.6 to 9.6. JMedium 6 consists of 0.2 

 gram (NH4)2S04, 0.5 gram MgS04, 0.25 gram CaClj, 3 grams 

 KH2PO4, trace of FeSOi and 10 grams of sulfur in 1000 cc. of 

 distilled water. This medium is sterilized in flowing steam, for 

 thirtj' minutes on three consecutive days. Its initial reaction 

 is pH = 4.0 to 4.8. jNIedium 10 consists of 5 grams Na2S203. 

 5H20, 0.1 grams NH4CI, 0.1 gram MgCU, 0.25 gram CaClj (or 

 10 grams Ca4(P04)2), 3 grams KH2PO4, 20 grams of agar in 1000 



'Paper no. 85 of the Journal Series, New Jersey Agricultural Experiment 

 Stations, Department of Soil Chemistry and Bacteriology. 



609 



