Methanogenic potential of a thermophilic consortium enriched from coal mine

• CBM65 consortium enriched from coal mines has potential to convert coal to methane.
• CBM65 exhibits 49% methane from the subbituminous coal at 65 °C.
• CBM65 comprises with Methanoculleus thermophiles and fermentative Comamonas sp.
• Jharia mines are methanogenically active and offer for coal bed methane extraction.

India is rich in coal bed methane resources but still lacks in methane development technologies. To begin understanding this prospective source, in the present investigation, microbial methane production was examined from bituminous, subbituminous and lignite coals obtained from Jharia coal mines in India. Microbial populations were enriched over a period of 21 days on various methanogenic specific substrates including the three ranks of coal. Maximum methane production (49%) was obtained on Methanosprillium sp specific medium (sodium acetate and isopropanol) supplemented with subbituminous coal at 65 °C and pH 6.8. Phylogenetic analysis of 16S rRNA gene sequences from the selected CBM65 consortium revealed a syntrophic association between a hydrogenotrophic methanogen Methanoculleus thermophiles and fermentative bacteria Comamonas sp. This is the first report of methane production by a consortium enriched from Indian coal bed methane reservoirs at such high temperature. The results of this study shed light on the fact that Jharia coal mines are methanogenically active and offer a prospective source for coal bed methane extraction. It is also, considered as the richest source of methane in India further this data will help in determining the potential role of methane emitted from this site in influencing the global carbon cycle.