Methanobacterium subterraneum sp. nov., a new alkaliphilic, eurythermic and halotolerant methanogen isolated from deep granitic groundwater

Abstract

Deep subterranean granitic aquifers have not been explored regarding methanogens until now. Three autotrophic methane-producing Archaea were isolated from deep granitic groundwater a t depths of 68,409 and 420 m. These organisms were non-motile, small, thin rods, 01-0-15 pm in diameter, and they could use hydrogen and carbon dioxide or formate as substrates for growth and methanogenesis. One of the isolates, denoted A8p, was studied in detail. It grew with a doubling time of 2.5 h under optimal conditions (2040 "C, pH 7.8-8.8 and 0.2-1.2 M NaCI). Strain A8p is eurythermic as it grew between 3-6 and 45 "C. It was resistant to up to 20 mg bacitracin I-'. The G+C content was 54.5 mol0/o, as determined by thermal denaturation. Phylogenetic studies based upon 16s rRNA gene sequence comparisons placed the isolate A8p in the genus Methanobacterium Phenotypic and phylogenetic characters indicate that the alkaliphilic, halotolerant strain A8p represents a new species. We propose the name Methanobacterium subterraneum for this species, and strain A8p (= DSM 110749 is the type strain.

Microbial dynamics in upflow anaerobic sludge blanket (UASB) bioreactor granules in response to short-term changes in substrate feed

“…S1), representing nearly 75 % of all clones analysed during the experiment. Methanogenic OTUs fell into two groups, those related to Methanobacterium subterraneum (OTU I-III), a halotolerant methanogen isolated from deep granitic groundwater, capable of growth on hydrogen or formate (Kotelnikova et al, 1998), and those related to Methanosaeta sp. (OTU IV-V), in which known species are capable of methanogenic growth on acetate, but not hydrogen or formate.…”

Shallow gas off the Rhône prodelta, Gulf of Lions

“…Hydrogen-rich and bioavailable organic substrates are associated with young, shallow sediments (Kotelnikova, 2002) which typically have the pore space to support methanogenic bacteria. Biogenic gas formation requires an anoxic environment 6 with available CO 2 and low sulfate concentrations (Oremland, 1988) with temperatures in the range of 9°C (Kotelnikova et al, 1998) to 110°C (Huber et al, 1994;Stetter, 1992). The upper temperature limit is associated with the maximum conditions at which subsurface methanogens are active.…”

Enhanced Microbial Pathways for Methane Production from Oil Shale

“…Biogenic methane is believed to consist of at least 20% and as high as 65% of the total methane storage on earth (Kotelnikova 2002;Rice 1981Rice , 1993. Actual biogenic methane production is accomplished by methanogenic Archaea, or simply called methanogens, which thrive in strictly anoxic environments that contain available CO 2 and low sulfate concentrations (Oremland 1988), and are exposed to temperatures between 9 o C and 110 o C (Kotelnikova et al 1998;Huber et al 1994).…”