Simple or complex organic substrates inhibit arsenite oxidation and aioA gene expression in two β-Proteobacteria strains

Publication date: Available online 25 September 2019Source: Research in MicrobiologyAuthor(s): Tiffanie Lescure, Catherine Joulian, Clément Charles, Taoikal Ben Ali Saanda, Mickael Charron, Dominique Breeze, Pascale Bauda, Fabienne Battaglia-BrunetAbstractMicrobial transformation of arsenic species and their interaction with the carbon cycle play a major role in the mobility of this toxic metalloid in the environment. The influence of simple or complex organic substrates on arsenic bio-oxidation was studied using two bacterial strains: one – the arsenivorans strain of Thiomonas delicata – is able to use AsIII as sole energy source; the other, Herminiimonas arsenicoxydans, is not. Experiments were performed at two AsIII concentrations (75 and 2 mg/L). At 75 mg/L As, for both strains, expression of aioA gene decreased when yeast extract concentration was raised from 0.2 to 1 g/L. At 2 mg/L As, the presence of either yeast extract or simple (succinate or acetate) organic substrates in the medium during bacterial growth decreased the AsIII-oxidation rate by both strains. When added specifically during oxidation test, yeast extract but not simple organic substrates seems to have a negative effect on AsIII oxidation. Taken together, results confirm the negative influence of simple or complex organic substrates on the kinetics of microbial AsIII oxidation and suggest that this effect results from different mechanisms depending on the type of organic substrate. Further, for the ...
Source: Research in Microbiology - Category: Microbiology Source Type: research