Polyhydroxyalkanoate-driven current generation via acetate by an anaerobic methanotrophic consortium

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Xueqin Zhang
  • Simon J. McIlroy
  • Igor Vassilev
  • Hesamoddin Rabiee
  • Manuel Plan
  • Chen Cai
  • Bernardino Virdis
  • Gene W. Tyson
  • Shihu Hu

Detail(s)

Original languageEnglish
Article number118743
Journal / PublicationWater Research
Volume221
Online published13 Jun 2022
Publication statusPublished - 1 Aug 2022
Externally publishedYes

Abstract

Anaerobic oxidation of methane (AOM) is an important microbial process mitigating methane (CH4) emission from natural sediments. Anaerobic methanotrophic archaea (ANME) have been shown to mediate AOM coupled to the reduction of several compounds, either directly (i.e. nitrate, metal oxides) or in consortia with syntrophic bacterial partners (i.e. sulfate). However, the mechanisms underlying extracellular electron transfer (EET) between ANME and their bacterial partners or external electron acceptors are poorly understood. In this study, we investigated electron and carbon flow for an anaerobic methanotrophic consortium dominated by ‘Candidatus Methanoperedens nitroreducens’ in a CH4-fed microbial electrolysis cell (MEC). Acetate was identified as a likely intermediate for the methanotrophic consortium, which stimulated the growth of the known electroactive genus Geobacter. Electrochemical characterization, stoichiometric calculations of the system, along with stable isotope-based assays, revealed that acetate was not produced from CH4 directly. In the absence of CH4, current was still generated and the microbial community remained largely unchanged. A substantial portion of the generated current in the absence of CH4 was linked to the oxidation of the intracellular polyhydroxybutyrate (PHB) and the breakdown of extracellular polymeric substances (EPSs). The ability of ‘Ca. M. nitroreducens’ to use stored PHB as a carbon and energy source, and its ability to donate acetate as a diffusible electron carrier expands the known metabolic diversity of this lineage that likely underpins its success in natural systems. © 2022 Elsevier Ltd. All rights reserved.

Research Area(s)

  • Anaerobic oxidation of methane (AOM), Extracellular electron transfer, Intermediates, Methanotrophic consortium, Polyhydroxyalkanoate, ‘Candidatus Methanoperedens nitroreducens’

Citation Format(s)

Polyhydroxyalkanoate-driven current generation via acetate by an anaerobic methanotrophic consortium. / Zhang, Xueqin; McIlroy, Simon J.; Vassilev, Igor et al.
In: Water Research, Vol. 221, 118743, 01.08.2022.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review