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Metabolic Engineering of Methanogenic Archaea for Biomethane Production from Renewable Biomass
Published in Sonil Nanda, Prakash K. Sarangi, Biomethane, 2022
Rajesh Kanna Gopal, Preethy P. Raj, Ajinath Dukare, Roshan Kumar
In biomethane production, CO2 is first reduced to form activated formylmethanofuran (Wagner et al., 2016) by reduced ferredoxin as an electron donor. Next, the formyl group is transferred to tetrahydromethanopterin in the second reaction. Dehydration and reduction take place in the formyl group to form methylene-tetrahydromethanopterin with reduced F420 as an electron donor (Liu and Whitman, 2008). Coenzyme M acts as a transferase and transfers methyl group from the methylene-tetrahydromethanopterin. Lastly, coenzyme B (CoB) as an electron donor reduces methyl-CoM to generate methane. Then the reduction of residual heterodisulfide (CoM-S-S-CoB) took place by the action of H2 to recycle coenzymes (Thauer et al., 2008; Liu and Whitman, 2008). In contrast to this, Methanothermobacter thermautotrophicus and Methanosarcina barkeri oxidize four molecules of CO to form CO2 by CO dehydrogenase enzyme and subjected to reduce into one molecule of CO2 to synthesize CH4 with H2 molecule as an electron donor (O’Brien et al., 1984; Daniels et al., 1977).
Current Advances in Methane Fermentation
Published in Yoshikatsu Murooka, Tadayuki Imanaka, Recombinant Microbes for Industrial and Agricultural Applications, 2020
Toshihide Kakizono, Naomichi Nishio
Extensive biochemical investigations have shown that six novel coenzymes are involved in methanogenesis: methanofuran, tetrahydromethanopterin (H4MPT), reduced deazaflavin (coenzyme F420), 2-mercaptoethanesulfonic acid (coenzyme M)/methylated coenzyme M, 7-mercaptoheptanoyl-threonine phosphate (HS-HTP), and Ni-bound factor F430 (tetrahydrocorphin) [see reviews 3,4]. However, even on the best-characterized methanogenic pathway from H2/C02 to methane, there is little knowledge on the enzymes in methanogenesis. For other substrates, although it has been presumed that some of the reductive reactions for the methyl group of methanol or acetate are in common with those of CO2 reduction by H2, the electron-yielding reactions of methanol or acetate in methanogenesis has remained unknown [5].
Physiology and Distribution of Anaerobic Oxidation of Methane by Archaeal Methanotrophs
Published in Susma Bhattarai Gautam, Performance Assessment and Enrichment of Anaerobic Methane Oxidising Microbial Communities from Marine Sediments in Bioreactors, 2018
Besides their close phylogenetic relationships, ANME exhibit other similarities with methanogenic archaea. For example, sequenced genomes of ANME-1 and ANME-2 from environmental samples indicate that, except for the N5, N10–methylene-tetrahydromethanopterin (H4MPT) reductase in the ANME-1 metagenome (Meyerdierks et al., 2010), these ANME contain homologous genes for the enzymes involved in all the seven steps of methanogenesis from CO2 (Haroon et al., 2013; Meyerdierks et al., 2010; Wang et al., 2014). Furthermore, with the exception of coenzyme M-S-S-coenzyme B heterodisulfide reductase, all those enzymes catalyzing the CH4 formation were confirmed to catalyze reversible reactions (Thauer, 2011; Scheller et al., 2010). Thus, it is hypothesized that ANME oxidize CH4via methanogenic enzymatic machinery functioning in reverse, i.e., reversal of CO2 reduction to CH4 (Hallam et al., 2004; Meyerdierks et al., 2010).
Potential methanogenic and degradation of nonylphenol ethoxylate from domestic sewage: unravelling the essential roles of nutritional conditions and microbial community
Published in Environmental Technology, 2023
Jeny Ventura, Franciele Pereira Camargo, Isabel Kimiko Sakamoto, Edson Luiz Silva, Maria Bernadete Amâncio Varesche
Several genes related to both acetoclastic and hydrogenotrophic methanogenesis could be inferred, such as acetyl-CoA synthetase (acs), acetate-CoA ligase (acss2), acetyl-CoA hydrolase (ach1p), among others related with acetoclastic methanogenesis, besides methenyltetrahydromethanopterin cyclohydrolase (n5), formylmethanofuran dehydrogenase (pf02663) and tetrahydromethanopterin S-methyltransferase (h4mpt) related to hydrogenotrophic methanogenesis. Methanosaeta, a strictly acetoclastic methanogen, stands out as the most abundant methanogenic genus observed in both assays (S4 = 22.62%; S5 = 22.61%), followed by Methanoregula (S4 = 4.33%; S5 = 4.38%), a strictly anaerobic H2/CO2-utilizing methanogen [72] (Figure 4).
Progress in microbiology for fermentative hydrogen production from organic wastes
Published in Critical Reviews in Environmental Science and Technology, 2019
[Fe]-hydrogenase is also named as H2-forming methylene-tetrahydromethanopterin dehydrogenase (Hmd) or iron–sulfur-cluster-free hydrogenase for it lacks iron–sulfur clusters. [Fe]-hydrogenase contains three clusters: Proximal cluster, Medial cluster and Distal cluster. Its active site is composed of an iron center, which is coordinated to a cysteine sulfur atom, two cis-CO ligands, a bidentate pyridone molecule through its nitrogen and acyl carbon atoms, and a yet unidentified ligand (Figure 3) (Chen, Scopelliti, & Hu, 2010). Unlike the clusters, the active site is buried.
Microbial and functional characterization of granulated sludge from full-scale UASB thermophilic reactor applied to sugarcane vinasse treatment
Published in Environmental Technology, 2022
Franciele Pereira Camargo, Isabel Kimiko Sakamoto, Tiago Palladino Delforno, Cédric Midoux, Iolanda Cristina Silveira Duarte, Edson Luiz Silva, Ariane Bize, Maria Bernadete Amâncio Varesche
Finally, the K00577, related to the tetrahydromethanopterin S-methyltransferase subunit A (mtrA) and part of the multienzymatic complex archaeon Methanobacterium thermoautotrophicum, is also involved in the CH4 production from CO2 and H2 (Equation (9)), by means of Methyl-CoM biosynthesis. However, the genus Methanobacterium was observed only in very low relative abundances in the studied samples (0.013 ± 0.0%).