Rumen

The rumen is a large pregastric fermentation compartment (foregut), which maintains a diverse but concentrated population of anaerobic bacteria, protozoa and fungi that are responsible for a variety of degradative and fermentative reactions. During this process biodegradable organic matter, mainly plant cell wall polymers, are converted into volatile fatty acids and microbial biomass that supply energy and protein to the host (ruminant) animal. An important reason for the evolution of foregut fermentation is detoxification of phytotoxins (of plant origin) and mycotoxins (of fungal origin). The concept of interspecies hydrogen transfer in which the mutually beneficial unidirectional transfer of hydrogen from a hydrogenproducing to a hydrogenutilising bacteria in a coupled reaction that maintains low partial pressures, which makes the transfer process hermodynamically feasible is important in ruminal methanogenesis. Currently, modern ‘Omics’ technologies are being applied to the study of rumen microbial ecology, genomics, metagenomics and metatranscriptomics.