Effects of alternative selenium and sulfur sources on dimethylselenide production by two fungi isolated from natural systems

The effects of different sulfur and selenium compounds on growth and dimethylselenide production by two fungi isolated from natural systems are appraised. High sulfite concentrations provide little protection from selenate toxicity. The ability of fungi to grow and methylate selenium in any natural system will be partly determined by the particular combination of selenium and sulfur sources present in the system. The apparent greater toxicity of selenate for the organisms could be a major contributing factor to the lack of reports of selenium volatilization in natural systems.