Anaerobic digestion (AD) is a complex multi-stage process relying on the activity of highly diverse microbial communities including hydrolytic, acidogenic and syntrophic acetogenic bacteria as well as methanogenic archaea. The lower diversity of methanogenic archaea compared to the bacterial groups involved in AD and the corresponding lack of functional redundancy cause a stronger susceptibilit...

The Earth’s early environment was relatively poor in oxygen, and observations and modeling indicate that the rise in oxygen levels did not occur until long after oxygen-enriching bacterial photosynthesis had developed. Catling et al. (p. 839; see the Perspective by Kasting) explain the apparent disconnect between oxygenation and the start of photosynthesis by adding methanogenesis to the proces...

The effects of probiotics, yucca extract, monensin and L-cysteine on rumen methanogenesis were determined by in vitro incubation using mixed bovine rumen microorganisms with ground Bermuda grass hay as a substrate. Two forms of probiotics, yucca extract, monensin and L-cysteine were tested during 24 hour anaerobic incubations. Methane and carbon dioxide production and fermentation characteristi...

Methanogenic archaea are a group of strictly anaerobic microorganisms characterized by their strict dependence on the process of methanogenesis for energy conservation. Among the archaea, they are also the only known group synthesizing proteins containing selenocysteine or pyrrolysine. All but one of the known archaeal pyrrolysine-containing and all but two of the confirmed archaeal selenocyste...

Anaerobic methane oxidation is a globally important but poorly understood process. Four lines of evidence have recently improved our understanding of this process. First, studies of recent marine sediments indicate that a consortium of methanogens and sulphate-reducing bacteria are responsible for anaerobic methane oxidation; a mechanism of 'reverse methanogenesis' was proposed, based on the pr...

A draft genome of Methanothermobacter sp. strain EMTCatA1 was reconstructed from a metagenome of a thermophilic electromethanogenic biocathode. This genome will provide information about methanogens catalyzing methanogenesis at the biocathodes.

The caecal fermentation pattern, including methanogenesis, was studied in young rabbits using in vitro batch incubations. Six conventional litters of eight rabbits each were used. At the age of 22, 25, 28, 32, 36, 42 and 56 days, an animal was slaughtered from each litter and its caecal contents were used for in vitro batch incubations at 39 degrees C/24 h. The incubated samples were analysed f...