Analysis of alkane-dependent methanogenic community derived from production water of a high-temperature petroleum reservoir

Abstract

Microbial assemblage in an n-alkanes-dependent thermophilic methanogenic enrichment cultures derived from production waters of a high-temperature petroleum reservoir was investigated in this study. Substantially higher amounts of methane were generated from the enrichment cultures incubated at 55 °C for 528 days with a mixture of long-chain n-alkanes (C(15)-C(20)). Stoichiometric estimation showed that alkanes-dependent methanogenesis accounted for about 19.8% of the total amount of methane expected. Hydrogen was occasionally detected together with methane in the gas phase of the cultures. Chemical analysis of the liquid cultures resulted only in low concentrations of acetate and formate. Phylogenetic analysis of the enrichment revealed the presence of several bacterial taxa related to Firmicutes, Thermodesulfobiaceae, Thermotogaceae, Nitrospiraceae, Dictyoglomaceae, Candidate division OP8 and others without close cultured representatives, and Archaea predominantly related to uncultured members in the order Archaeoglobales and CO(2)-reducing methanogens. Screening of genomic DNA retrieved from the alkanes-amended enrichment cultures also suggested the presence of new alkylsuccinate synthase alpha-subunit (assA) homologues. These findings suggest the presence of poorly characterized (putative) anaerobic n-alkanes degraders in the thermophilic methanogenic enrichment cultures. Our results indicate that methanogenesis of alkanes under thermophilic condition is likely to proceed via syntrophic acetate and/or formate oxidation linked with hydrogenotrophic methanogenesis.

Anaerobic oxidation of long-chain n-alkanes by the hyperthermophilic sulfate-reducing archaeon, Archaeoglobus fulgidus

“…The relative increase in sulfide production with time ( Figure 1) suggested growth of A. fulgidus on these saturated hydrocarbons. Interestingly, Mbadinga et al (2012) recently showed that the archaeal community of a thermophilic methanogenic enrichment culture oxidizing long-chain alkanes in the absence of sulfate as terminal electron acceptor was dominated by members of the order Archaeoglobales. Although the dominant phylotype was moderately related to cultured organisms (90-93% similarities), these data together with our work suggest that some Archaeoglobales-related species, such as A. fulgidus or relatives (for example, A. sulfaticallidus PM70-1), are involved in the anaerobic oxidation of long-chain hydrocarbons.…”

(Per)chlorate reduction at high temperature: Physiological study of Archaeoglobus fulgidus and potential implications for novel souring mitigation strategies

“…However, in the environment compounds other than sulfide may also act as efficient scavengers for the reduction and detoxification of chlorite. Potential candidates may be ferrous iron or manganese (II) or organic compounds that are present in the environment of A. fulgidus, such as hydrocarbons (Kaster et al, 2009;Mbadinga et al, 2012).…”

Diversity of Benzylsuccinate Synthase-Like ( bssA ) Genes in Hydrocarbon-Polluted Marine Sediments Suggests Substrate-Dependent Clustering

“…Four nmsA sequences retrieved from SRB isolates or sulfate-reducing enrichment cultures (8,9,18) clustered together with nmsA sequences recently detected in environmental samples of different origins (38). Additionally, orthologues of assA and masD genes were recently found in pure cultures of sulfate-reducing and denitrifying Proteobacteria (22,39) and in a thermophilic methanogenic community (40). Analysis of retrieved sequences revealed that assA sequences grouped into a distinct cluster that was separated from canonical bssA sequences.…”