Methanogenesis and sulfate reduction in timber and drainage water from a gold mine

Biogenesis of methane in the heartwood of diseased trees has been shown, but never in timber in service. Studies were undertaken to establish whether methan‐ogens and sulfate‐reducers were present in wooden pit props and drainage water from underground sites in a gold mine. The predominant methanogen in the mine ecosystem was tentatively identified as Methanobacterium bryantii. The sulfate‐reducers comprised Desulfovibrio desulfuricans and Desulfotomaculum antarcticum. Most probable numbers (MPN) of bacteria indicated that 3.5 × 10⁵ methanogenic and 7.9 × 10³ sulfate‐reducing bacteria were present per milliliter of stagnant drainage water. MPN values per gram of timber were lower for methanogens but comparable for sulfate‐reducers. Laboratory model systems predicted a maximum rate of methan‐ogenesis of 2.3 mL methane/g wood per day; however, rates would never attain this value because of nutrient limitations and environmental restrictions. Analysis of gas samples extracted from sealed areas of the gold mine verified the presence of methane.