Changes in the Substrate Source Reveal Novel Interactions in the Sediment-Derived Methanogenic Microbial Community

Abstract

Methanogenesis occurs in many natural environments and is used in biotechnology for biogas production. The efficiency of methane production depends on the microbiome structure that determines interspecies electron transfer. In this research, the microbial community retrieved from mining subsidence reservoir sediment was used to establish enrichment cultures on media containing different carbon sources (tryptone, yeast extract, acetate, CO2/H2). The microbiome composition and methane production rate of the cultures were screened as a function of the substrate and transition stage. The relationships between the microorganisms involved in methane formation were the major focus of this study. Methanogenic consortia were identified by next generation sequencing (NGS) and functional genes connected with organic matter transformation were predicted using the PICRUSt approach and annotated in the KEGG. The methane production rate (exceeding 12.8 mg CH4 L−1 d−1) was highest in the culture grown with tryptone, yeast extract, and CO2/H2. The analysis of communities that developed on various carbon sources casts new light on the ecophysiology of the recently described bacterial phylum Caldiserica and methanogenic Archaea representing the genera Methanomassiliicoccus and Methanothrix. Furthermore, it is hypothesized that representatives of Caldiserica may support hydrogenotrophic methanogenesis.

Higher Abundance of Sediment Methanogens and Methanotrophs Do Not Predict the Atmospheric Methane and Carbon Dioxide Flows in Eutrophic Tropical Freshwater Reservoirs

“…In fact, the Anaerolineae class may form syntrophic cooperation with methanogens (Liang et al, 2015), which were also observed for UCG-001 (de Leeuw et al, 2019). Similarly, Syntrophorhabdus, Syntrophus, and Smithella spp., from the Deltaproteobacteria class, and Caldisericum spp., from Caldisericia class, present in the same brown network, have demonstrated this syntrophic potential previously (Mountfort et al, 1984;Guyot and Brauman, 1986;Liu et al, 1999;Qiu et al, 2008;Szafranek-Nakonieczna et al, 2019), although a direct interaction with Methanobacterium spp. was not detected here.…”

“…It can be explained by the fact that methanogenesis potential in freshwater sediments may be influenced by the activity of other microbial community members or by substrate availability, besides the presence of methanogenic microorganisms (Chaudhary et al, 2017). Microbial enrichment experiments with sediments from a reservoir in Poland corroborate to higher CH 4 production with a reduced proportion of methanogens (Szafranek-Nakonieczna et al, 2019), suggesting uncoupling of abundance and activity. This is observed in our study for the first time in field samples of tropical freshwater reservoirs.…”

Microbial Involvement in Carbon Transformation via CH4 and CO2 in Saline Sedimentary Pool

“…Simultaneously, control samples, three times autoclaved (for 30 min at 121 • C and 15 psi) rock, were prepared and incubated in the same conditions. Changes in methane and carbon dioxide concentrations over time were determined using a Varian CP-3800 gas chromatograph equipped with flame ionization (FID, 200 • C) and thermal conductivity (TCD, 120 • C) detectors [13,30,31]. CH 4 production and CO 2 release rate (respiration) were determined on the basis of increase in methane or carbon dioxide concentration over time while methane oxidation was based on methane decrease and expressed respectively in nmol CH 4 gdw −1 day −1 and nmol CO 2 gdw −1 day −1 .…”