This study presents a novel procedure for accelerating methanogenesis from wastewater by adding elemental manganese into the anaerobic digestion system. The results indicated that elemental manganese effectively enhanced both the methane yield and the production rate. Compared to the control test without elemental manganese, the total methane yield and production rate with 4 g/L manganese addit...

The suppression of methanogens affects the performance of Microbial Fuel Cells (MFCs), but its degree of importance is application dependent. In terms of Coulombic Efficiency (CE), avoiding methanogenesis is essential for MFC type volatile fatty acid (VFA) sensors but less critical for scaled-up MFCs removing COD from real wastewater. To study the suppression of methanogenesis, different H-type...

Methanogenesis and its key small-molecule methyltransferase Mtr complex are poorly understood despite their pivotal role in Earth's global carbon cycle. Mtr complex is encoded by a conserved mtrEDCBAFGH operon in most methanogens. Here we report that two discrete lineages, Methanococcales and Methanomicrobiales, have a noncanonical mtr operon carrying two copies of mtrA resulting from an ancien...

Lake Mendota sediments were studied to determine the role of H2 in sediment methanogenesis. H2 was generally not detectable in sediment. The addition of H2 to sediment significantly increased methanogenensis. The amount of methane produced was proportional to the concentration of hydrogen added. H2 addition stimulated the reduction of CO2 to methane, but did not significantly stimulate the conv...

In methanogenic Archaea, the final step of methanogenesis generates methane and a heterodisulfide of coenzyme M and coenzyme B (CoM-S-S-CoB). Reduction of this heterodisulfide by heterodisulfide reductase to regenerate HS-CoM and HS-CoB is an exergonic process. Thauer et al. [Thauer, et al. 2008 Nat Rev Microbiol 6:579-591] recently suggested that in hydrogenotrophic methanogens the energy of h...

The factors that regulate methanogenesis in humans have not been established. The presence of bile acid, which is lost into the colon from the small intestine, may be an important regulatory factor of methanogenesis. To examine this possibility, the effect of human bile on methane production by faecal cultures, and the in vivo effect of biliary diversion on breath methane excretion in a methano...

The effects of freeze-thaw, freezing and sediment geochemistry on terminal anaerobic processes occurring in sediments taken from below cyanobacterial mats in meltwater ponds of the McMurdo Ice Shelf in Antarctica were investigated. Depending on the geochemical and physical status of the sediments (i.e., frozen or thawed), as well as passage of sediment through a freeze-thaw cycle, terminal carb...

Several compounds were evaluated in vitro as alternative electron sinks to ruminal methanogenesis. They were incubated with ruminal fluid, buffer mixture, and finely ground alfalfa hay for 24 h, at 0, 6, 12, and 18 mM initial concentrations. The propionate enhancer oxaloacetic acid, the butyrate enhancer beta-hydroxybutyrate, and the butyrate unsaturated analog 3-butenoic acid were ineffective ...

Using an isotope-mass balance approach and assuming the equimolar production of CO2 and CH4 from methanogenesis (e.g., anaerobic decomposition of cellulose), we calculate that the proportion of total CO2 production frommethanogenesis varies from 37 to 83% across a variety of northern peatlands. In a relative sense, methanogenesis was a more important pathway for decomposition in bogs (80 ± 13% ...