Microbial Production of Methane From Wood and Inhibiition by Ethanol Extracts of Wood

Mixed cultures of anaerobic bacteria fermented both coniferous and deciduous wood sawdust, with concomitant methane production. A consistently greater lag in methanogenesis was observed on coniferous as compared to deciduous wood. Arabinose, glucose, galactose, mannose, rhamnose and xylose when added to enrichment cultures had either no effect or a slight stimulation of CH4 production in the absence of added methane precursors (acetate, formate, CO2, H2). In the presence of added acetate, formate, CO2 and H2; arabinose, rhamnose and xylose appeared to stimulate mixed culture methanogenesis; whereas, xylose retarded methanogenesis in pure cultures of Methanobacterium formicicum. Alcohol extracts of either deciduous or coniferous wood were inhibitory to methanogenesis from either mixed cultures or from M. formicicum. The greater amount of alcohol extractives in coniferous wood may explain the greater lag in methanogenesis when compared to that of deciduous wood. OHIO J. SCI. 80(6): 242, 1980 The production of CH4 from the microbial fermentation of wood and other cellulosic materials observed since the last century suggested that cellulosic waste might become a minor alternative energy source through the microbial production of methane (Maugh 1972). Knowledge of the biological ecosystem responsible for fermentation of wood to methane is limited. Our report investigated the role of 2 types of wood as ultimate sources of methane in a mixed culture system and the influence of wood fractions on the ultimate genesis of methane in both the mixed culture system and pure cultures of methanogenic bacteria. MATERIALS AND METHODS