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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).
Methanogens and MIC
Published in Kenneth Wunch, Marko Stipaničev, Max Frenzel, Microbial Bioinformatics in the Oil and Gas Industry, 2021
Timothy J. Tidwell, Zachary R. Broussard
Methylotrophic methanogenesis starts with the activation of one-carbon compounds (methylamines, methanol, methylated sulfides, or methoxylated compounds) to methyl coenzyme M (CH3-CoM). Methylotrophs are further broken into two groups, those that are obligately H2 dependent and those that are H2 independent (Vanwonterghem, et al. 2016). H2 independent methylotrophs consist of members of Methanosarcinales that possess cytochromes. These cytochromes allow for the oxidation of methyl groups to CO2 via a membrane-bound electron transport chain (Lang, et al. 2015). Within the H2-independent pathway present in Methanosarcinales, about 75 % of the CH3-CoM is reduced via mcr to produce CH4, but about 25 % of CH3-CoM is oxidized to CO2 via AOM (Timmers, et al. 2017). The oxidation pathway is required to provide reducing agents needed for the reduction of CH3-CoM by mcr. The H2-dependent methylotrophs include Methanomassiliicoccales and many of the recently proposed methylotrophs use H2 as the electron donor for the reduction of methyl-groups.
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].
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
Regarding the other KO observed in lower proportions (≤0.001%), most of them were related with the genera Methanothermobacter and Methanosarcina. It is worth to mention that K14081, K14080 and K04480 were exclusively related to the genus Methanosarcina in the present study. The two first enzymes are part of the complex [methyl-Co (III) methanol-specific corrinoid protein]: coenzyme M methyltransferase, and it is involved in methanogenesis from methanol. In the same way, the K04480 is also involved only in methanogenesis from methanol, being this KO a methanol-5-hydroxybenzimidazolylcobamide Co-methyltransferase, which catalyses the transfer of methyl groups from methanol to a methanol-specific corrinoid protein.