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 Thiobacil lus thioparus THI 115 was found to hydrolyse thiocyanate to carbonyl s ulfide (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 thiocyana te. COS was incorporated into the cells during further incubation, and could not be detected in the head space. Activated sludge for the tre atment of thiocyanate, which contained T. thioparus as a thiocyanate-d egrading bacterium, also showed emission followed by disappearance of COS in the head space when incubated with thiocyanate. These results p rovide evidence for the biogenic origin of COS which may play an impor tant role in acid rain precipitation and the greenhouse effect.