09:30 〜 09:52
[BCG07-03] Microbe-mineral interaction: exploring the diversity of microbial metalloids transformations
★Invited Papers
キーワード：アンチモン、ヒ素、生物還元、鉄還元
Arsenic (As) and antimony (Sb) are naturally occurring toxic metalloids that are considered to be emerging environmental pollutants. These metalloids predominantly exist in trivalent (III) and pentavalent (V) forms and are often strongly adsorbed with Fe(III) oxyhydroxides in natural systems. Microorganisms have evolved cellular mechanisms to catalyze the redox transformation of these toxic metalloids, and microbe-mineral interactions play important roles in the geochemical cycling of both iron and metalloids in the environment.
This study aims to characterize the diverse microbial metalloids transformation pathways and to investigate microbe-mineral interactions in metal-impacted environments utilizing geochemical, electrochemical and genomic approaches. Through multiple cultivation efforts, various metalloid-oxidizing bacteria representing phylogenetically diverse groups were isolated. Genomic analyses revealed the involvement of arsenite oxidase (Aio)-related enzymes in the oxidation of As(III) and Sb(III), coupled to O2 reduction, and in some cases, nitrate reduction.
Furthermore, an anaerobic consortium was enriched for its ability to reduce Sb(V) as well as ferrihydrite and Sb(V)-adsorbed ferrihydrite, potentially via extracellular electron transfer mechanisms. Microbial reduction of Fe(III) could lead to the release of toxic metalloids bound to Fe(III) oxyhydroxides, thus potentially impacting the mobility of Sb and As in contaminated soils. This study also undertook further examination of microbial populations possessing extracellular electron transfer capabilities in mine wastewater, and the application of in situ electrochemical enrichment will be discussed.
This study aims to characterize the diverse microbial metalloids transformation pathways and to investigate microbe-mineral interactions in metal-impacted environments utilizing geochemical, electrochemical and genomic approaches. Through multiple cultivation efforts, various metalloid-oxidizing bacteria representing phylogenetically diverse groups were isolated. Genomic analyses revealed the involvement of arsenite oxidase (Aio)-related enzymes in the oxidation of As(III) and Sb(III), coupled to O2 reduction, and in some cases, nitrate reduction.
Furthermore, an anaerobic consortium was enriched for its ability to reduce Sb(V) as well as ferrihydrite and Sb(V)-adsorbed ferrihydrite, potentially via extracellular electron transfer mechanisms. Microbial reduction of Fe(III) could lead to the release of toxic metalloids bound to Fe(III) oxyhydroxides, thus potentially impacting the mobility of Sb and As in contaminated soils. This study also undertook further examination of microbial populations possessing extracellular electron transfer capabilities in mine wastewater, and the application of in situ electrochemical enrichment will be discussed.