Carbon nanotubes accelerate methane production in pure cultures of methanogens and in a syntrophic coculture
authors Salvador, AF; Martins, G; Melle-Franco, M; Serpa, R; Stams, AJM; Cavaleiro, AJ; Pereira, MA; Alves, MM
nationality International
journal ENVIRONMENTAL MICROBIOLOGY
keywords INTERSPECIES ELECTRON-TRANSFER; SLUDGE BLANKET REACTORS; ANAEROBIC-DIGESTION; ACTIVATED CARBON; PELOBACTER-CARBINOLICUS; BACTERIAL CYTOTOXICITY; WASTE-WATER; PADDY SOIL; METABOLISM; PROPIONATE
abstract Carbon materials have been reported to facilitate direct interspecies electron transfer (DIET) between bacteria and methanogens improving methane production in anaerobic processes. In this work, the effect of increasing concentrations of carbon nanotubes (CNT) on the activity of pure cultures of methanogens and on typical fatty acid-degrading syntrophic methanogenic coculture was evaluated. CNT affected methane production by methanogenic cultures, although acceleration was higher for hydrogenotrophic methanogens than for acetoclastic methanogens or syntrophic coculture. Interestingly, the initial methane production rate (IMPR) by Methanobacterium formicicum cultures increased 17 times with 5 g. Butyrate conversion to methane by Syntrophomonas wolfei and Methanospirillum hungatei was enhanced (approximate to 1.5 times) in the presence of CNT (5 gL(-1)), but indications of DIET were not obtained. Increasing CNT concentrations resulted in more negative redox potentials in the anaerobic microcosms. Remarkably, without a reducing agent but in the presence of CNT, the IMPR was higher than in incubations with reducing agent. No growth was observed without reducing agent and without CNT. This finding is important to re-frame discussions and re-interpret data on the role of conductive materials as mediators of DIET in anaerobic communities. It also opens new challenges to improve methane production in engineered methanogenic processes.
publisher WILEY
issn 1462-2912
isbn 1462-2920
year published 2017
volume 19
issue 7
beginning page 2727
ending page 2739
digital object identifier (doi) 10.1111/1462-2920.13774
web of science category Microbiology
subject category Microbiology
unique article identifier WOS:000405907300017
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journal impact factor 4.933
5 year journal impact factor 5.453
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