BIOMETHYLATION OF INORGANIC ANTIMONY COMPOUNDS BY AN AEROBIC FUNGUS -SCOPULARIOPSIS BREVICAULIS

Various metals and metalloids can be converted by a variety of microor ganisms to their volatile methyl derivatives. These bioconversions are important from an environmental perspective because they take place o ver long time periods and the products have quite different properties (e.g., transportation, toxicological) as compared to the inorganic sp ecies from which they are derived. Whereas the biomethylation of arsen ic is well established, that of the closely related element antimony i s not, and there are no reports of antimony methylation by monoseptic microbial cultures. We report here, for the first time, the formation of trimethylantimony [(CH3)(3)Sb] by a characterized microorganism, Sc opulariopsis brevicaulis, grown aerobically in the presence of inorgan ic antimony. Volatile antimony evolved into the headspace above the fu ngal cultures was quantified by remote trapping and analysis by induct ively coupled plasma-mass spectrometry (ICP-MS). The existence of biog enic trimethylantimony was established, following exclusion of oxygen from cultures after growth, by remote trapping of volatile compounds a nd analysis by gas chromatography with compound-specific (mass spectro metry) or element-specific (atomic absorption) detection. No other vol atile product containing antimony was detected in culture headspace ga ses.