BalticMethanosarcinaandClostridiumcompete for electrons from metallic iron

Abstract

13Microbial induced corrosion of steel structures, used for transport or storage of fuels, 14 chemical weapons or waste radionuclides, is an environmental and economic threat. 15In non-sulfidic environments, the exact role of methanogens in steel corrosion is 16 poorly understood. From the non-sulfidic, methanogenic sediments of the Baltic Sea 17 corrosive communities were enriched using exclusively Fe 0 as electron donor and 18 CO 2 as electron acceptor. Methane and acetate production were persistent for three 19 years of successive transfers. Methanosarcina and Clostridium were attached to the 20 Fe 0 , and dominated metagenome libraries. Since prior reports indicated 21Methanosarcina were merely commensals, consuming the acetate produced by 22 acetogens, we investigated whether these methanogens were capable of Fe 0 corrosion 23 without bacterial partners (inhibited by an antibiotic cocktail). Unassisted, 24 methanogens corroded Fe 0 to Fe 2+ at similar rates to the mixed community. 25 Surprisingly, in the absence of competitive bacteria, Baltic-Methanosarcina produced 26 six times more methane than they did in the mixed community. This signifies that 27Baltic-Methanosarcina achieved better corrosion alone, exclusive of an operative 28 bacterial partner. Our results also show that together with acetogens, Methanosarcina 29 interact competitively to retrieve electrons from Fe 0 rather than as commensals as 30 previously assumed. 31 32

Ontological Tools in Anaerobic Fermentation Technologies: Bioinformation Database Applications

“…Figure 9. Estimated commensual interaction between Fe 0chordinator Clostridium-acetogen and acetate-utilized Methanosarcina-methanogen: 1a direct mechanism of electron absorption; 2an absorption mechanism based on abiotic H2 [7] Thus, in the study [8] direct absorption of electron from Fe 0 for Methanobacterium strain IM1, because:…”

High-Level Abundances ofMethanobacterialesandSyntrophobacteralesMay Help To Prevent Corrosion of Metal Sheet Piles

“…A recent study by Yee et al (83) showed the ability of Methanosarcina species to directly accept electrons from insoluble electron donors, including conductive particles and biocathodes that show similarities to the metal sheet piles in our study. A study by Jaramillo et al (84) observed a competition of Methanosarcina species with acetogens in nonsulfidic environments. The study's observations of higher methanogenesis rates without a mixed community that includes Clostridiales indicated a competition to obtain electrons from elemental iron.…”