IDENTIFICATION OF EXTRACELLULAR ARSENICAL METABOLITES IN THE GROWTH-MEDIUM OF THE MICROORGANISMS APIOTRICHUM-HUMICOLA AND SCOPULARIOPSIS-BREVICAULIS

The separation and identification of some of the arsenic species produ ced in cells present in the growth medium when the microorganisms Apio trichum humicola (previously known as Candida humicola) and Scopulario psis brevicaulis were grown in the presence of arsenicals were achieve d by using hydride generation-gas chromatography-atomic absorption spe ctrometry methodology (HG GC AA). Arsenite, monomethylarsonate, dimeth ylarsinate and trimethylarsine oxide were detected following incubatio n with arsenate. With arsenite as a substrate, the metabolites were mo nomethylarsonate, dimethylarsinate and trimethylarsine oxide; monometh ylarsonate afforded dimethylarsinate and trimethylarsine oxide, and di methylarsinate afforded trimethylarsine oxide. Trimethylarsine was not detected when the arsenic concentration was 1 ppm.