Abundance, activity, sensibility and efficiency of methanogenic organisms in natural habitats

Wien

2014

S. 17

Artikel aus einer ZeitschriftUnselbständiges Werk

200190101

Methane (CH4) constitutes a potent greenhouse gas that is emitted from anthropogenic and natural origins. Wetlands comprise the largest individual natural sources of CH4, accounting for 20-40% of the total methane budget. Although wetlands cover only 3% of the earth´s surface, these ecosystems are of significant importance in terms of carbon storage and sequestration. Apart from aquatic ecosystems, there is abundant evidence of methanogenic activity in aerobic upland soils, thus playing a major role in the global carbon cycle. Methanogenesis, the biogenic formation of methane, represents the final step in the anaerobic decay of organic matter by methanogenic archaea inhabiting natural soil and wetland ecosystems, which are characterized by a high spatial and temporal heterogeneity as well as seasonal and climatic variability. Methane generation in biogas plants, however, requires the maintenance of favorable conditions, since methanogenic archaea are highly sensitive to changed parameters causing process failure. This leads to the question whether methanogenic organisms in natural habitats are adapted to frequently changing environmental conditions and whether this ability can be used to improve the efficiency and stability of anaerobic degradation processes in biogas plants. To address this question, the present study focusses on the isolation as well as enrichment of methanogenic organisms from soil and wetland ecosystems. Soil and peat samples will be collected from local study sites. With the purpose of evaluating the contributing biotic and abiotic factors exerting an impact on the establishment and activity of the microbiocenosis in lab scale culture experiments, single parameter variation studies (e.g., pH, temperature, oxygen content) will be performed to detect indications of possible adaptive capabilities of the engaged microorganisms. Common molecular-biological techniques are intended to provide an insight into microbial diversity of these cultures, particularly into the functional relationship of the dominant phylogenetic groups, thus improving the understanding of environment-rganism interactions. Further studies shall ultimately contribute to implement methanogenic organisms with a broad eco-physiological potential and high resilience into fermentations, with the aim of achieving a higher efficiency and productivity of biogas plants.