A new model for electron flow during anaerobic digestion: direct interspecies electron transfer to Methanosaeta for the reduction of carbon dioxide to methane
Amelia-Elena Rotaru,Pravin Malla Shrestha,Fanghua Liu,Minita Shrestha,Devesh Shrestha,Mallory Embree,Karsten Zengler,Colin Wardman,Kelly P. Nevin,Derek R. Lovley +9 more
TLDR
In this article, a metatranscriptomic analysis of methanogenic aggregates from a brewery wastewater digester, coupled with fluorescence in situ hybridization with specific 16S rRNA probes, revealed that Methanosaeta species were the most abundant and metabolically active methanogens.Abstract:
Anaerobic conversion of organic wastes and biomass to methane is an important bioenergy strategy, which depends on poorly understood mechanisms of interspecies electron transfer to methanogenic microorganisms. Metatranscriptomic analysis of methanogenic aggregates from a brewery wastewater digester, coupled with fluorescence in situ hybridization with specific 16S rRNA probes, revealed that Methanosaeta species were the most abundant and metabolically active methanogens. Methanogens known to reduce carbon dioxide with H2 or formate as the electron donor were rare. Although Methanosaeta have previously been thought to be restricted to acetate as a substrate for methane production, Methanosaeta in the aggregates had a complete complement of genes for the enzymes necessary for the reduction of carbon to methane, and transcript abundance for these genes was high. Furthermore, Geobacter species, the most abundant bacteria in the aggregates, highly expressed genes for ethanol metabolism and for extracellular electron transfer via electrically conductive pili, suggesting that Geobacter and Methanosaeta species were exchanging electrons via direct interspecies electron transfer (DIET). This possibility was further investigated in defined co-cultures of Geobacter metallireducens and Methanosaeta harundinacea which stoichiometrically converted ethanol to methane. Transcriptomic, radiotracer, and genetic analysis demonstrated that M. harundinacea accepted electrons via DIET for the reduction of carbon dioxide to methane. The discovery that Methanosaeta species, which are abundant in a wide diversity of methanogenic environments, are capable of DIET has important implications not only for the functioning of anaerobic digesters, but also for global methane production.read more
Citations
More filters
Journal ArticleDOI
Extracellular electron transfer mechanisms between microorganisms and minerals
Liang Shi,Hailiang Dong,Gemma Reguera,Haluk Beyenal,Anhuai Lu,Juan Liu,Han-Qing Yu,James K. Fredrickson +7 more
TL;DR: The molecular mechanisms that underlie the ability of microorganisms to exchange electrons, such as c-type cytochromes and microbial nanowires, with extracellular minerals and with microorganisms of the same or different species are discussed.
Journal ArticleDOI
Electroactive microorganisms in bioelectrochemical systems
TL;DR: The diversity of exoelectrogenic and electrotrophic microorganisms and their functions provide new opportunities for electrochemical devices, such as microbial fuel cells that generate electricity or microbial electrolysis cells that produce hydrogen or methane.
Journal ArticleDOI
Direct Interspecies Electron Transfer between Geobacter metallireducens and Methanosarcina barkeri
Amelia-Elena Rotaru,Pravin Malla Shrestha,Fanghua Liu,Beatrice Markovaite,Shanshan Chen,Shanshan Chen,Kelly P. Nevin,Derek R. Lovley +7 more
TL;DR: M. barkeri is the second methanogen found to accept electrons via DIET and the first meetinghanogen known to be capable of using either H2 or electrons derived from DIET for CO2 reduction, making it a model organism for elucidating mechanisms by which methanogens make biological electrical connections with other cells.
Journal ArticleDOI
Promoting Interspecies Electron Transfer with Biochar
Shanshan Chen,Amelia-Elena Rotaru,Pravin Malla Shrestha,Nikhil S. Malvankar,Fanghua Liu,Wei Fan,Kelly P. Nevin,Derek R. Lovley +7 more
TL;DR: The finding that biochar can stimulate DIET may be an important consideration when amending soils with biochar and can help explain why biochar may enhance methane production from organic wastes under anaerobic conditions.
Journal ArticleDOI
Magnetite Particles Triggering a Faster and More Robust Syntrophic Pathway of Methanogenic Propionate Degradation
TL;DR: It is shown that supplementation of micrometer-size magnetite particles to a methanogenic sludge enhanced (up to 33%) the methane production rate from propionate, a key intermediate in the anaerobic digestion of organic matter and a model substrate to study energy-limited syntrophic communities.
References
More filters
Journal ArticleDOI
Mapping and quantifying mammalian transcriptomes by RNA-Seq.
TL;DR: Although >90% of uniquely mapped reads fell within known exons, the remaining data suggest new and revised gene models, including changed or additional promoters, exons and 3′ untranscribed regions, as well as new candidate microRNA precursors.
Journal ArticleDOI
Quality control and preprocessing of metagenomic datasets
Robert Schmieder,Robert Edwards +1 more
TL;DR: PRINSEQ is presented for easy and rapid quality control and data preprocessing of genomic and metagenomic datasets and can be used as a stand alone version or accessed online through a user-friendly web interface.
Journal ArticleDOI
MEGAN analysis of metagenomic data
TL;DR: MEGAN, a new computer program that allows laptop analysis of large metagenomic data sets, is introduced and provides graphical and statistical output for comparing different data sets.
Journal ArticleDOI
Extracellular electron transfer via microbial nanowires.
Gemma Reguera,Kevin D. McCarthy,Teena Mehta,Julie S. Nicoll,Mark T. Tuominen,Derek R. Lovley +5 more
TL;DR: Results indicate that the pili of G. sulfurreducens might serve as biological nanowires, transferring electrons from the cell surface to the surface of Fe(iii) oxides, indicating possibilities for other unique cell-surface and cell–cell interactions, and for bioengineering of novel conductive materials.
Journal ArticleDOI
Domestic Wastewater Treatment as a Net Energy Producer–Can This be Achieved?
TL;DR: Newer membrane processes coupled with complete anaerobic treatment of wastewater offer the potential for wastewater treatment to become a net generator of energy, rather than the large energy consumer that it is today.