Enrichment of Mesophilic and Thermophilic Mixed Microbial Consortia for Syngas Biomethanation: The Role of Kinetic and Thermodynamic Competition

Antonio Grimalt_Alemany, Mateusz Łężyk, David M. Kennes-Veiga, Ioannis V Skiadas, Hariklia N. Gavala*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Mixed culture-based syngas biomethanation is a robust bioconversion process with high versatility in terms of exploitable feedstocks and potential applications, as it could be operated independently, or coupled to anaerobic digestion systems and in-situ biogas upgrading processes. Typically, the syngas biomethanation consists in the stepwise conversion of syngas into methane through a number of catabolic routes, which may vary considerably depending on the operating conditions. In this study, two enrichments were performed at 37 °C and 60 °C to investigate the effect of the incubation temperature on the microbial selection process and the dominant catabolic routes followed. This was carried out through the characterization of the catabolic routes and the microbial composition of the enriched cultures, and a thermodynamic feasibility study on their metabolic networks. The enrichments resulted in two stable microbial consortia with different patterns of activity. The mesophilic enriched consortium presented a more intricate metabolic network composed by four microbial trophic groups, where aceticlastic methanogenesis contributed to 64.9 ± 8.3% of the CH4 production. The metabolic network of the thermophilic enriched consortium was much simpler, consisting in the syntrophic association of carboxydotrophic hydrogenogens and hydrogenotrophic methanogens. This led to significant differences in methane productivity, corresponding to 1.83 ± 0.27 and 33.48 ± 0.90 mmol CH4/g VSS/h for the mesophilic and the thermophilic enriched consortium, respectively, which would potentially make the thermophilic consortium more suited for industrial applications. 16S rRNA gene amplicon analysis indicated the presence of strains with similarity to Acetobacterium sp., Methanospirillum hungateii, Methanospirillum stamsii and Methanothrix sp. at mesophilic conditions, and Thermincola carboxydiphila and Methanothermobacter sp. at thermophilic conditions, implying a role in the conversion of syngas. The thermodynamic feasibility study demonstrated that the microbial selection was not driven solely by kinetic competition, since thermodynamic limitations also played a significant role defining the dominant catabolic routes.
Original languageEnglish
JournalWaste and Biomass Valorization
ISSN1877-2641
DOIs
Publication statusAccepted/In press - 2019

Keywords

  • Carbon monoxide
  • Hydrogen
  • Methane
  • Mixed cultures
  • Syngas
  • Thermodynamics

Cite this

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title = "Enrichment of Mesophilic and Thermophilic Mixed Microbial Consortia for Syngas Biomethanation: The Role of Kinetic and Thermodynamic Competition",
abstract = "Mixed culture-based syngas biomethanation is a robust bioconversion process with high versatility in terms of exploitable feedstocks and potential applications, as it could be operated independently, or coupled to anaerobic digestion systems and in-situ biogas upgrading processes. Typically, the syngas biomethanation consists in the stepwise conversion of syngas into methane through a number of catabolic routes, which may vary considerably depending on the operating conditions. In this study, two enrichments were performed at 37 °C and 60 °C to investigate the effect of the incubation temperature on the microbial selection process and the dominant catabolic routes followed. This was carried out through the characterization of the catabolic routes and the microbial composition of the enriched cultures, and a thermodynamic feasibility study on their metabolic networks. The enrichments resulted in two stable microbial consortia with different patterns of activity. The mesophilic enriched consortium presented a more intricate metabolic network composed by four microbial trophic groups, where aceticlastic methanogenesis contributed to 64.9 ± 8.3{\%} of the CH4 production. The metabolic network of the thermophilic enriched consortium was much simpler, consisting in the syntrophic association of carboxydotrophic hydrogenogens and hydrogenotrophic methanogens. This led to significant differences in methane productivity, corresponding to 1.83 ± 0.27 and 33.48 ± 0.90 mmol CH4/g VSS/h for the mesophilic and the thermophilic enriched consortium, respectively, which would potentially make the thermophilic consortium more suited for industrial applications. 16S rRNA gene amplicon analysis indicated the presence of strains with similarity to Acetobacterium sp., Methanospirillum hungateii, Methanospirillum stamsii and Methanothrix sp. at mesophilic conditions, and Thermincola carboxydiphila and Methanothermobacter sp. at thermophilic conditions, implying a role in the conversion of syngas. The thermodynamic feasibility study demonstrated that the microbial selection was not driven solely by kinetic competition, since thermodynamic limitations also played a significant role defining the dominant catabolic routes.",
keywords = "Carbon monoxide, Hydrogen, Methane, Mixed cultures, Syngas, Thermodynamics",
author = "Antonio Grimalt_Alemany and Mateusz Łężyk and Kennes-Veiga, {David M.} and Skiadas, {Ioannis V} and Gavala, {Hariklia N.}",
year = "2019",
doi = "10.1007/s12649-019-00595-z",
language = "English",
journal = "Waste and Biomass Valorization",
issn = "1877-2641",
publisher = "Springer Netherlands",

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TY - JOUR

T1 - Enrichment of Mesophilic and Thermophilic Mixed Microbial Consortia for Syngas Biomethanation: The Role of Kinetic and Thermodynamic Competition

AU - Grimalt_Alemany, Antonio

AU - Łężyk, Mateusz

AU - Kennes-Veiga, David M.

AU - Skiadas, Ioannis V

AU - Gavala, Hariklia N.

PY - 2019

Y1 - 2019

N2 - Mixed culture-based syngas biomethanation is a robust bioconversion process with high versatility in terms of exploitable feedstocks and potential applications, as it could be operated independently, or coupled to anaerobic digestion systems and in-situ biogas upgrading processes. Typically, the syngas biomethanation consists in the stepwise conversion of syngas into methane through a number of catabolic routes, which may vary considerably depending on the operating conditions. In this study, two enrichments were performed at 37 °C and 60 °C to investigate the effect of the incubation temperature on the microbial selection process and the dominant catabolic routes followed. This was carried out through the characterization of the catabolic routes and the microbial composition of the enriched cultures, and a thermodynamic feasibility study on their metabolic networks. The enrichments resulted in two stable microbial consortia with different patterns of activity. The mesophilic enriched consortium presented a more intricate metabolic network composed by four microbial trophic groups, where aceticlastic methanogenesis contributed to 64.9 ± 8.3% of the CH4 production. The metabolic network of the thermophilic enriched consortium was much simpler, consisting in the syntrophic association of carboxydotrophic hydrogenogens and hydrogenotrophic methanogens. This led to significant differences in methane productivity, corresponding to 1.83 ± 0.27 and 33.48 ± 0.90 mmol CH4/g VSS/h for the mesophilic and the thermophilic enriched consortium, respectively, which would potentially make the thermophilic consortium more suited for industrial applications. 16S rRNA gene amplicon analysis indicated the presence of strains with similarity to Acetobacterium sp., Methanospirillum hungateii, Methanospirillum stamsii and Methanothrix sp. at mesophilic conditions, and Thermincola carboxydiphila and Methanothermobacter sp. at thermophilic conditions, implying a role in the conversion of syngas. The thermodynamic feasibility study demonstrated that the microbial selection was not driven solely by kinetic competition, since thermodynamic limitations also played a significant role defining the dominant catabolic routes.

AB - Mixed culture-based syngas biomethanation is a robust bioconversion process with high versatility in terms of exploitable feedstocks and potential applications, as it could be operated independently, or coupled to anaerobic digestion systems and in-situ biogas upgrading processes. Typically, the syngas biomethanation consists in the stepwise conversion of syngas into methane through a number of catabolic routes, which may vary considerably depending on the operating conditions. In this study, two enrichments were performed at 37 °C and 60 °C to investigate the effect of the incubation temperature on the microbial selection process and the dominant catabolic routes followed. This was carried out through the characterization of the catabolic routes and the microbial composition of the enriched cultures, and a thermodynamic feasibility study on their metabolic networks. The enrichments resulted in two stable microbial consortia with different patterns of activity. The mesophilic enriched consortium presented a more intricate metabolic network composed by four microbial trophic groups, where aceticlastic methanogenesis contributed to 64.9 ± 8.3% of the CH4 production. The metabolic network of the thermophilic enriched consortium was much simpler, consisting in the syntrophic association of carboxydotrophic hydrogenogens and hydrogenotrophic methanogens. This led to significant differences in methane productivity, corresponding to 1.83 ± 0.27 and 33.48 ± 0.90 mmol CH4/g VSS/h for the mesophilic and the thermophilic enriched consortium, respectively, which would potentially make the thermophilic consortium more suited for industrial applications. 16S rRNA gene amplicon analysis indicated the presence of strains with similarity to Acetobacterium sp., Methanospirillum hungateii, Methanospirillum stamsii and Methanothrix sp. at mesophilic conditions, and Thermincola carboxydiphila and Methanothermobacter sp. at thermophilic conditions, implying a role in the conversion of syngas. The thermodynamic feasibility study demonstrated that the microbial selection was not driven solely by kinetic competition, since thermodynamic limitations also played a significant role defining the dominant catabolic routes.

KW - Carbon monoxide

KW - Hydrogen

KW - Methane

KW - Mixed cultures

KW - Syngas

KW - Thermodynamics

U2 - 10.1007/s12649-019-00595-z

DO - 10.1007/s12649-019-00595-z

M3 - Journal article

JO - Waste and Biomass Valorization

JF - Waste and Biomass Valorization

SN - 1877-2641

ER -