Temperature regulation of anaerobic degradation of organic matter

Anaerobic degradation of organic matter follows similar pathways in digesters and anaerobic freshwater sediments. The responsible microorganisms are linked in a complex food web, where short chain fatty acids and H₂ are important intermediates. Degradation of short-chain fatty acids is endothermic under standard conditions and is only possible at low H₂ partial pressures maintained by exothermic methanogenesis. The coupling between these endothermic and exothermic processes is delicate, and hence sensitive to environmental changes such as temperature variations. The effect of temperature on thermodynamics and on kinetics of these and other anaerobic degradation processes with emphasis on freshwater ecosystems is discussed.The author is with the Department of General Microbiology, Institute of Molecular Biology, University of Copenhagen, Sølvgade 83 H, DK-1307 Copenhagen K, Denmark