Factors affecting the volatilization of dimethylselenide by Enterobacter cloacae SLD1a-1

The facultative anaerobic bacterium Enterobacter cloacae SLD1a-1 (ATCC 700258), capable of reducing selenate (SeO42−) and selenite (SeO32−) to elemental selenium (Se0), was found to volatilize dimethylselenide (DMSe) in the presence of SeO32−. The effect of temperature, pH and electrical conductivity (EC) on the ability of E. cloacae SLD1a-1 to methylate selenium (Se) were investigated in a liquid medium of tryptic soy broth containing 10 μM SeO32−. Optimum Se volatilization occurred at a pH, temperature and EC of 6.5, 35°C and 11 dS m−1, respectively. Volatilization of Se was also found to be concentration dependent, as E. cloacae SLD1a-1 produced 11.3 times more DMSe at a SeO32− concentration of 10 μM than at 1.0 μM. By determining the optimum environmental conditions which stimulate Se volatilization, it may be possible to design a strategy to remediate seleniferous water.