EFFECTS OF ALKYLTIN COMPOUNDS ON HYDROGEN-OXIDIZING ANAEROBIC-BACTERIA

Methyl and butyltin compounds were inhibitory to all anaerobes examined, but there were great variations, depending on the specific alkyltin and bacterium. The methanogens were inhibited more strongly by methyl than by butyl derivatives; more than 50% inhibition occurred with 0.025-0.5 m M of the methyltins, whereas 0.16-1.8 m M butyltins were needed for the same level of inhibition; tri-butyltin was the least toxic. Methanosarcina barkeri was, in general, more resistant than the Methanococcus sp. and Methanobacterium bryantii. The Desulfovibrio were more strongly inhibited by mono-methyltin than by di- and tri-methyl derivatives; butyltins were, in general, not so toxic. Mono-methyltin at 0.15 m M almost completely inhibited three of the sulfate reducers, but Desulfovibrio thermophilus required 0.7 m M for this level of inhibition. Tri-butyltin at 1.8 m M did not cause major inhibition, whereas mono- and di-butyltins were more inhibitory. Acetobacterium woodii was most affected by mono- and dimethyltins, and least by tri-methyltin and mono-butyltin. In contrast, Wollinella succinogenes was most affected by tri-methyltin. This study suggests several major groups of anaerobes thought to be involved in metal biocorrosion vary greatly in their response to alkyltins; most interesting is the relative insensitivity by methanogens and sulfate reducers to tri-butyltin, which is a major component in commercial antifouling paints. Our results differ considerably from those reported for aerobic microorganisms, which were found to be most affected by tributyltin. © 1990 Springer-Verlag New York Inc.