M. A. Khan, H. H. Ngo, and W. S. Guo, Optimization of process parameters for production of volatile fatty acid, biohydrogen and methane from anaerobic digestion, Bioresour Technol, vol.219, pp.738-786, 2016.

M. Götz, J. Lefebvre, and F. Mörs, Renewable power-to-gas: a technological and economic review, Renew Energy, vol.85, pp.1371-90, 2016.

R. Kadam and N. L. Panwar, Recent advancement in biogas enrichment and its applications, Renew Sustain Energy Rev, vol.73, pp.892-903, 2017.

S. Sarker, J. J. Lamb, and D. R. Hjelme, Overview of recent progress towards in situ biogas upgradation techniques, Fuel, vol.226, pp.686-97, 2018.

I. Angelidaki, L. Treu, and P. Tsapekos, Biogas upgrading and utilization: current status and perspectives, Biotechnol Adv, vol.36, pp.452-66, 2018.

B. Lecker, L. Illi, and A. Lemmer, Biological hydrogen methanation-a review, Bioresour Technol, vol.245, pp.1220-1228, 2017.

J. Zabranska and D. Pokorna, Bioconversion of carbon dioxide to methane using hydrogen and hydrogenotrophic methanogens, Biotechnol Adv, vol.36, pp.707-727, 2018.

G. Luo and I. Angelidaki, Integrated biogas upgrading and hydrogen utilization in an anaerobic reactor containing enriched hydrogenotrophic methanogenic culture, Biotechnol Bioeng, vol.109, pp.2729-2765, 2012.

G. Luo, S. Johansson, and K. Boe, Simultaneous hydrogen utilization and in situ biogas upgrading in an anaerobic reactor, Biotechnol Bioeng, vol.109, pp.1088-94, 2012.

M. Balat, Potential importance of hydrogen as a future solution to environmental and transportation problems, Int J Hydrogen Energy, vol.33, pp.4013-4042, 2008.

L. Deng and M. B. Hägg, Techno-economic evaluation of biogas upgrading process using CO 2 facilitated transport membrane, Int J Greenh Gas Control, vol.4, pp.638-684, 2010.

B. Schink, Energetics of syntrophic cooperation in methanogenic degradation, Microbiol Mol Biol Rev, vol.61, pp.262-80, 1997.

T. Amani, M. Nosrati, and S. M. Mousavi, Using enriched cultures for elevation of anaerobic syntrophic interactions between acetogens and methanogens in a high-load continuous digester, Bioresour Technol, vol.102, pp.3716-3739, 2011.

L. T. Angenent, K. Karim, and M. H. Al-dahhan, Production of bioenergy and biochemicals from industrial and agricultural wastewater, Trends Biotechnol, vol.22, pp.477-85, 2004.

N. Aryal, T. Kvist, and F. Ammam, An overview of microbial biogas enrichment, Bioresour Technol, vol.264, pp.359-69, 2018.

D. G. Mulat, F. Mosbaek, and A. J. Ward, Exogenous addition of H 2 for an in situ biogas upgrading through biological reduction of carbon dioxide into methane, Waste Manag, vol.68, pp.146-56, 2017.

R. Wahid, D. G. Mulat, and J. C. Gaby, Effects of H 2:CO 2 ratio and H 2 supply fluctuation on methane content and microbial community composition during in situ biological biogas upgrading, Biotechnol Biofuels, vol.12, pp.1-15, 2019.

E. A. Cazier, E. Trably, and J. P. Steyer, Biomass hydrolysis inhibition at high hydrogen partial pressure in solid-state anaerobic digestion, Bioresour Technol, vol.190, pp.106-119, 2015.
URL : https://hal.archives-ouvertes.fr/hal-01149953

I. Bassani, P. G. Kougias, and L. Treu, Biogas upgrading via hydrogenotrophic methanogenesis in two-stage continuous stirred tank reactors at mesophilic and thermophilic conditions, Environ Sci Technol, vol.49, pp.12585-93, 2015.

L. M. Agneessens, L. Ottosen, and M. Andersen, Parameters affecting acetate concentrations during in situ biological hydrogen methanation, Bioresour Technol, vol.258, pp.33-40, 2018.

T. Kern, J. Theiss, and K. Röske, Assessment of hydrogen metabolism in commercial anaerobic digesters, Appl Microbiol Biotechnol, vol.100, pp.4699-710, 2016.

L. Treu, P. G. Kougias, and B. De-diego-díaz, Two-year microbial adaptation during hydrogen-mediated biogas upgrading process in a serial reactor configuration, Bioresour Technol, vol.264, pp.140-147, 2018.

L. Treu, S. Campanaro, and P. G. Kougias, Hydrogen-fueled microbial pathways in biogas upgrading systems revealed by genome-centric metagenomics, Front Microbiol, vol.9, p.1079, 2018.

L. M. Agneessens, L. Ottosen, and N. V. Voigt, In-situ biogas upgrading with pulse H2 additions: the relevance of methanogen adaption and inorganic carbon level, Bioresour Technol, vol.233, pp.256-63, 2017.

F. Paillet, A. Marone, and R. Moscoviz, Improvement of biohydrogen production from glycerol in micro-oxidative environment, Int J Hydrogen Energy, vol.44, pp.17802-17814, 2019.
URL : https://hal.archives-ouvertes.fr/hal-02623263

I. Angelidaki and W. Sanders, Assessment of the anaerobic biodegradability of macropollutants, Rev Environ Sci Biotechnol, vol.3, pp.117-146, 2004.

A. Cohen, R. J. Zoetemeyer, and A. Deursen, Anaerobic digestion of glucose with separated acid production and methane formation, Water Res, vol.13, pp.571-80, 1979.

J. Carrillo-reyes, L. B. Celis, and F. Alatriste-mondragón, Different start-up strategies to enhance biohydrogen production from cheese whey in UASB reactors, Int J Hydrogen Energy, vol.37, pp.5591-601, 2012.

I. Angelidaki, M. Alves, and D. Bolzonella, Defining the biomethane potential (BMP) of solid organic wastes and energy crops: a proposed protocol for batch assays, Water Sci Technol, vol.59, pp.927-961, 2009.

E. Elbeshbishy, G. Nakhla, and H. Hafez, Biochemical methane potential (BMP) of food waste and primary sludge: influence of inoculum pre-incubation and inoculum source, Bioresour Technol, vol.110, pp.18-25, 2012.

X. S. Jia, H. Furumai, and H. Fang, Yields of biomass and extracellular polymers in four anaerobic sludges, Environ Technol (United Kingdom), vol.17, pp.283-91, 1996.

R. Liu, X. Hao, and J. Wei, Function of homoacetogenesis on the heterotrophic methane production with exogenous H 2 /CO 2 involved, Chem Eng J, vol.284, pp.1196-203, 2016.

L. Rachbauer, R. Beyer, and G. Bochmann, Characteristics of adapted hydrogenotrophic community during biomethanation, Sci Total Environ, vol.595, pp.912-921, 2017.

J. J. Lay, Y. Y. Li, and T. Noike, Interaction between homoacetogens and methanogens in lake sediments, J Ferment Bioeng, vol.86, pp.467-71, 1998.

A. G. Hashimoto, Methane production from beef cattle manure: effects of temperature, hydraulic retention time and influent substrate concentration, Biotechnol Bioeng, vol.24, pp.2039-52, 1982.

P. Weiland, Biogas production: current state and perspectives, Appl Microbiol Biotechnol, vol.85, pp.849-60, 2010.

L. Treu, P. G. Kougias, and S. Campanaro, Deeper insight into the structure of the anaerobic digestion microbial community; The biogas microbiome database is expanded with 157 new genomes, Bioresour Technol, vol.216, pp.260-266, 2016.

J. Hassa, I. Maus, and S. Off, Metagenome, metatranscriptome, and metaproteome approaches unraveled compositions and functional relationships of microbial communities residing in biogas plants, Appl Microbiol Biotechnol, vol.102, pp.5045-63, 2018.

K. Schuchmann and V. Müller, Autotrophy at the thermodynamic limit of life: a model for energy conservation in acetogenic bacteria, Nat Rev Microbiol, vol.12, pp.809-830, 2014.

A. Willems and M. D. Collins, Phylogenetic relationships of the genera Acetobacterium and Eubacterium sensu stricto and reclassification of Eubacterium alactolyticum as Pseudoramibacter alactolyticus gen. nov., comb. nov, Int J Syst Bacteriol, vol.46, pp.1083-1090, 1996.

L. Rago, S. Zecchin, and S. Marzorati, A study of microbial communities on terracotta separator and on biocathode of air breathing microbial fuel cells, Bioelectrochemistry, vol.120, pp.18-26, 2018.

M. Calusinska, X. Goux, and M. Fossépré, A year of monitoring 20 mesophilic full-scale bioreactors reveals the existence of stable but different core microbiomes in bio-waste and wastewater anaerobic digestion systems, Biotechnol Biofuels, vol.11, pp.1-19, 2018.
URL : https://hal.archives-ouvertes.fr/hal-02328143

J. A. Fitzgerald, D. M. Wall, and S. A. Jackson, Trace element supplementation is associated with increases in fermenting bacteria in biogas monodigestion of grass silage, Renew Energy, vol.138, pp.980-986, 2019.

Y. Niimura, K. Komagata, and M. Kozaki, Anaerobic sporeforming xylan-digesting bacterium which lacks cytochrome, quinone, and catalase, Int J Syst Bacteriol, vol.5, pp.297-301, 1990.

A. H. Togo, S. Khelaifia, and J. C. Lagier, Noncontiguous finished genome sequence and description of Paenibacillus ihumii sp. nov. strain AT5, New Microbes New Infect, vol.10, pp.142-150, 2016.
URL : https://hal.archives-ouvertes.fr/hal-01479520

L. Wang, Y. S. Cui, and C. S. Kwon, Vagococcus acidifermentans sp. nov., isolated from an acidogenic fermentation bioreactor, Int J Syst Evol Microbiol, vol.61, pp.1123-1129, 2011.

T. N. Zhilina, D. G. Zavarzina, and G. A. Osipov, Natronincola ferrireducens sp. nov., and Natronincola peptidovorans sp. nov., new anaerobic alkaliphilic peptolytic iron-reducing bacteria isolated from soda lakes, Microbiology, vol.78, pp.455-67, 2009.

L. Niu, L. Song, and X. Dong, Proteiniborus ethanoligenes gen. nov., sp. nov., an anaerobic protein-utilizing bacterium, Int J Syst Evol Microbiol, vol.58, pp.12-18, 2008.

A. N. Padden, V. M. Dillon, and J. Edmonds, An indigo-reducing moderate thermophile from a woad vat, Clostridium isatidis sp. nov, Int J Syst Bacteriol, vol.49, pp.1025-1056, 1999.

X. Qu, L. Mazéas, and V. A. Vavilin, Combined monitoring of changes in ?13CH4 and archaeal community structure during mesophilic methanization of municipal solid waste, FEMS Microbiol Ecol, vol.68, pp.236-281, 2009.
URL : https://hal.archives-ouvertes.fr/hal-02594862

L. Hao, F. Lü, and L. Li, Response of anaerobes to methyl fluoride, 2-bromoethanesulfonate and hydrogen during acetate degradation, J Environ Sci (China), vol.25, pp.857-64, 2013.

J. De-vrieze, S. Gildemyn, and R. Vilchez-vargas, Inoculum selection is crucial to ensure operational stability in anaerobic digestion, Appl Microbiol Biotechnol, vol.99, pp.189-99, 2014.

X. Chen, L. Ottosen, and M. Kofoed, How low can you go: methane production of methanobacterium congolense at low CO 2 concentrations, Front Bioeng Biotechnol, vol.7, pp.1-10, 2019.

J. De-vrieze, T. Hennebel, and N. Boon, Methanosarcina: the rediscovered methanogen for heavy duty biomethanation, Bioresour Technol, vol.112, pp.1-9, 2012.

I. Bio2e, Environmental Biotechnology and Biorefinery Platform, vol.46854, p.12

, Standard methods for the examination of water and wastewater analysis

R. J. Zoetemeyer, J. C. Van-den-heuvel, and A. Cohen, pH influence on acidogenic dissimilation of glucose in an anaerobic digestor, Water Res, vol.16, pp.303-314, 1982.

F. E. Mosey, Mathematical modelling of the anaerobic digestion process: regulatory mechanisms for the formation of short-chain volatile fatty acids from glucose, Water Sci Technol, vol.15, pp.209-241, 1983.

D. J. Costello, P. F. Greenfield, and P. L. Lee, Dynamic modelling of a singlestage high-rate anaerobic reactor-I. Model derivation, Water Res, vol.25, pp.847-58, 1991.

J. I. Horiuchi, T. Shimizu, and K. Tada, Selective production of organic acids in anaerobic acid reactor by pH control, Bioresour Technol, vol.82, pp.209-222, 2002.

R. Moscoviz, E. Trably, and N. Bernet, Consistent 1,3-propanediol production from glycerol in mixed culture fermentation over a wide range of pH, Biotechnol Biofuels, vol.9, 2016.
URL : https://hal.archives-ouvertes.fr/hal-01509040

A. A. Carmona-martínez, E. Trably, and K. Milferstedt, Long-term continuous production of H <inf>2</inf> in a microbial electrolysis cell (MEC) treating saline wastewater, Water Res, vol.81, pp.149-56, 2015.

K. Venkiteshwaran, K. Milferstedt, and J. Hamelin, Anaerobic digester bioaugmentation influences quasi steady state performance and microbial community, Water Res, vol.104, pp.128-164, 2016.
URL : https://hal.archives-ouvertes.fr/hal-01608636

F. Braun, J. Hamelin, and G. Gèvaudan, Development and application of an enzymatic and cell flotation treatment for the recovery of viable microbial cells from environmental matrices such as anaerobic sludge, Appl Environ Microbiol, vol.77, pp.8487-93, 2011.
URL : https://hal.archives-ouvertes.fr/hal-02652112

K. Xu, H. Liu, and G. Du, Real-time PCR assays targeting formyltetrahydrofolate synthetase gene to enumerate acetogens in natural and engineered environments, Anaerobe, vol.15, pp.204-217, 2009.

P. J. Mcmurdie and S. Holmes, Phyloseq: an R package for reproducible interactive analysis and graphics of microbiome census data, PLoS ONE, 2013.

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