Specific enrichment of hyperthermophilic electroactive Archaea from deep-sea hydrothermal vent on electrically conductive support

Guillaume Pillot (1) , Eléonore E Frouin (1) , Emilie Pasero (1) , Anne Godfroy (2) , Yannick Combet-Blanc (1) , Sylvain Davidson (1) , Pierre-Pol Liebgott (1)

1 MIO - Institut méditerranéen d'océanologie
2 LM2E - Laboratoire de microbiologie des environnements extrêmophiles

While more and more investigations are done to study hyperthermophilic exoelectrogenic communities from environments, none have been performed yet on deep-sea hydrothermal vent. Samples of black smoker chimney from Rainbow site on the Atlantic mid-oceanic ridge have been harvested for enriching exoelectrogens in microbial electrolysis cells under hyperthermophilic (80 °C) condition. Two enrichments were performed in a BioElectrochemical System specially designed: one from direct inoculation of crushed chimney and the other one from inoculation of a pre-cultivation on iron (III) oxide. In both experiments, a current production was observed from 2.4 A/m² to 5.8 A/m² with a set anode potential of -0.110 V vs Ag/AgCl. Taxonomic affiliation of the exoelectrogen communities obtained on the electrode exhibited a specific enrichment of Archaea belonging to Thermococcales and Archeoglobales orders, even when both inocula were dominated by Bacteria. .

Keywords: Hyperthermophilic exoelectrogens; Deep-sea hydrothe rmal vent; Microbial electrolysis cell; External Electron Transfer

Domains: Environmental Sciences; Biodiversity and Ecology

Guillaume Pillot, Eléonore E Frouin, Emilie Pasero, Anne Godfroy, Yannick Combet-Blanc, et al.. Specific enrichment of hyperthermophilic electroactive Archaea from deep-sea hydrothermal vent on electrically conductive support. Bioresource Technology, 2018, 259, pp.304-311. ⟨10.1016/j.biortech.2018.03.053⟩. ⟨hal-02049432⟩