Biogenic methane generation using solutions from column reactions of lignite with hydrogen peroxide

A microbial consortium associated with coal from the coal-bearing Soya Formation in the Tempoku Coalfield (northern Hokkaido, Japan) was cultivated with reaction solutions of lignite and hydrogen peroxide (H2O2) (i.e., chemically solubilized lignite) to evaluate in situ biogenic methane generation. Column experiments with H2O2 flowing through pulverized lignite achieved maximum concentrations of dissolved organic carbon, acetic acid, and formic acid of 6330, 612, and 1810 mg/L, respectively. Cultivation experiments using the above reaction solution as a substrate for methanogens produced nearly 6 cm3 CH4 per g lignite with a maximum rate of 0.14 cm3 per g per day. Pyrosequencing analysis of the microbial consortium after cultivation confirmed the presence of methanogens, such as Methanoregulaceae and Methanosarcinaceae, as the dominant archaea in the culture. The observed production of biogenic methane from a reaction solution of lignite and H2O2 under the simulated conditions indicates the potential for successful in situ microbially enhanced coalbed methane generation using H2O2.