UPTAKE AND DEGRADATION OF ARSENOBETAINE BY THE MICROORGANISMS OCCURRING IN SEDIMENTS

We have reported the degradation of arsenobetaine [(CH3)(3)As+CH2COO-] to inorganic arsenic by microorganisms from various marine origins su ch as sediments. However, there was no information as to the fate of t he ingested arsenobetaine within the body of the microorganisms before excretion. In this study, arsenobetaine and sediments were added to t wo culture media (1/5 Zobell 2216E and a solution of inorganic salts) and aerobically incubated at 25 degrees C in the dark. Despite the deg radation and complete disappearance of arsenobetaine from the filtrate s of the incubation mixtures, the major arsenic compound from the micr oorganisms harvested from the mixtures was identified by HPLC as arsen obetaine throughout the incubation period. The presence of arsenobetai ne was further confirmed by TLC and fast atom bombardment mass spectro metry (FAB MS). A minor arsenical also present in the incubated microo rganisms, dimethylarsinic acid, was detected.