EMISSION OF CARBONYL SULFIDE BY THIOBACILLUS-THIOPARUS GROWN WITH THIOCYANATE IN PURE AND MIXED CULTURES

When grown in the presence of thiocyanate, a pure culture of Thiobacillus thioparus THI 115 was found to hydrolyse thiocyanate to carbonyl sulfide (COS). The maximum amount of COS detected in the head space of a sealed flask was 2.2 mumol which represented 0.2% of total thiocyanate. COS was incorporated into the cells during further incubation, and could not be detected in the head space. Activated sludge for the treatment of thiocyanate, which contained T. thioparus as a thiocyanate-degrading bacterium, also showed emission followed by disappearance of COS in the head space when incubated with thiocyanate. These results provide evidence for the biogenic origin of COS which may play an important role in acid rain precipitation and the greenhouse effect.