Antimony biomethylation by the wood rotting fungus Phaeolus schweinitzii

The wood rotting fungus, Phaeolus schweinitzii, efficiently transforms the antimony(III) compounds potassium antimony tartrate and antimony trioxide t o nonvolatile dimethylantimony and trimethylantimony species, The organoant imony species were detected in potato dextrose broth media samples by using hydride generation-gas chromatography-atomic absorption spectroscopy (HG-G C-AAS). The average concentrations of trimethylantimony species after 40 da ys incubation with potassium antimony tartrate were approximately 35 mug, 1 55 mug and 520 mug Sb/l, for substrate concentrations of 10 mg, 100 mg and 1000 mg Sb/l respectively. Thus, the maximum yield of trimethylantimony spe cies was approximately 0.4%, When antimony trioxide (saturated solution, 4 mg Sb/l) was used as a substrate, the average concentration of trimethylant imony species was 150 mug Sb/l after 40 days. The HG-GC-AAS response for th e dimethylantimony species was less than that for the trimethylantimony spe cies; however, quantification was not possible because of the lack of an ap propriate standard. In comparison, cultures of P, schweinitzii incubated wi th 1 mg As/I as sodium arsenite contained approximately 200 mug As/I as tri methylarsenic species, i.e. 20% yield, Biomethylation of antimony(V) was in efficient: cultures contained only 3 mug Sb/l as trimethylantimony species after incubation with 100 mg Sb/l as potassium hexahydroxyantimonate, No or ganoantimony species were detected in control cultures that contained only medium and inorganic antimony compounds. The identities of the organoantimo ny species were confirmed by using CC-Mass Spectrometry, Copyright (C) 2001 John Wiley & Sons, Ltd.