Carbon monoxide conversion by anaerobic bioreactor sludges

Seven different anaerobic sludges from wastewater treatment reactors were screened for their ability to convert carbon monoxide (CO) at 30 and 55 degrees C. At 30 degrees C, CO was converted to methane and/or acetate by all tested sludges. Inhibition experiments, using 2-bromoethanesulfonic acid and vancomycine, showed that CO conversion to methane at 30 degrees C occurred via acetate, but not via H2. At 55 degrees C, four sludges originally cultivated at 30-35 degrees C and one sludge cultivated at 55 degrees C converted CO rapidly into hydrogen or into methane. In the latter case, inhibition experiments showed that methane was formed via hydrogen as the intermediate.