Ethanol conversion to methane by a coal microbial community

•Ethanol was converted to CH4 by a coal microbial community without other additives.•The extent and rate of ethanol conversion to CH4 was enhanced by other amendments.•Ethanol may have mobilized smaller biodegradable molecules in the coal matrix.

The potential of added ethanol to enhance the rate and extent of biogenic conversion of coal to methane was investigated. Small amounts of methane were slowly produced from unamended Big George coal collected from the Powder River Basin. Added ethanol was partially converted to methane by a microbial community in the coal in the absence of other amendments. The extent and rate of ethanol conversion to methane was enhanced by the addition of a buffered, mineral salts medium and a coal derived microbial community. The pattern of methane production suggested that a fraction of the added ethanol first adsorbed to coal and then was degraded to methane after desorption. The addition of a solvent, like ethanol, may assist with the solubilization of coal constituents to facilitate more rapid and more extensive production of biogenic methane from coal.