Rumen methanogens: a review

Abstract

The Methanogens are a diverse group of organisms found in anaerobic environments such as anaerobic sludge digester, wet wood of trees, sewage, rumen, black mud, black sea sediments , etc which utilize carbon dioxide and hydrogen and produce methane. They are nutritionally fastidious anaerobes with the redox potential below -300 mV and usually grow at pH range of 6.0-8.0 [1]. Substrates utilized for growth and methane production include hydrogen, formate, methanol, methylamine, acetate, etc. They metabolize only restricted range of substrates and are poorly characterized with respect to other metabolic, biochemical and molecular properties.

Effects of hydrogen in headspace and bicarbonate in media on rumen fermentation, methane production and methanogenic population using in vitro gas production techniques

“…The interactive effects of H 2 and NaHCO 3 additions on the populations of M. barkeri, M. stadtmanae, M. ruminantium and M. smithii were consisted with previous report of Sirohi et al (2010). In that report, CO 2 and H 2 were considered to be directly used by M. ruminantium, M. smithii and M. barkeri to produce CH 4 .…”

Rumen Microbiology: An Overview

“…Methanogenic archaea, considered as the earliest organisms originated in our planet, are phyllogenetically widespread and represent three of the seven classes in the phylum Euryarchaeota (Sirohi et al 2010 ;Singh and Sirohi 2012 ). These rumen microorganisms utilize the H 2 and CO 2 produced by the protozoa, fungi, and bacteria from the catabolism of hexoses to produce CH 4 and generate ATP (Albers et al 2007 ;Ferry and Kastead 2007 ), which benefi ts the donors by providing an electron sink for reducing equivalents to minimize the partial pressure of H 2 (Wolin and Miller 1988 ;Lange et al 2005 ) inside the rumen.…”

Metagenome changes in the mesophilic biogas-producing community during fermentation of the green alga Scenedesmus obliquus

“…10). The main difference between the two genera of Methanosarcinales is that the members of the genus Methanosarcina are able to carry out all three pathways of methanogenesis, i.e., hydrogenotrophic, acetoclastic, and methylotrophic (Sirohi et al, 2010), while Methanosaeta can function only in the acetoclastic mode. Similarly, to our previous results (Wirth et al, 2015), the feeding with the microalgal biomass did not cause any appreciable changes in the methanogenic community.…”