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Get salty with me : acetate production through homoacetogenesis in (hyper)saline conditions

Tyler Arbour (UGent)
Author
Organization
Abstract
Homoacetogenesis has become a hot topic, with industry interest, as a bio-process that can convert waste CO2 directly to a valorizable product (organic acids). However, the microorganisms catalyzing this reaction have remained little explored outside of their original discovery and later in the pioneering work on a few isolates in elucidation of the Wood-Ljungdahl pathway. We are exploring homoacetogenesis in saline environments for two main reasons: i) application in microbial electrosynthesis (MES) reactors under saline conditions, where salinity decreases ohmic resistance and inhibits competing methanogens by salt stress; and ii) fundamental microbiological interest. Motivating questions include: Can we find and enrich for novel salt-tolerant homoacetogens from un- or underexplored environments? Where is homoacetogenesis most active in the depth/redox profile of saline soil and sediment? We collected samples from North Atlantic coastal marine sediment (10 m.b.s.l.) and from high-altitude (3921 m.a.s.l.) shallow salt lakes of the Argentinian Andes. Serum-flask enrichments of North Sea samples in a homoacetogen seawater medium (35 g/L salinity) using a headspace of H2/CO2 (80/20 vol%) showed an initial period of acetate production (1-2 g/L in two weeks) from the top 10 cm of sediment, followed by a switch to methanogenesis. Samples collected from a salt lake in Argentina ranged in salinity from ~10 to 90 g/L total salts. We therefore explored the correlation between environmental salinity and acetate-production capacity in culture media of 20, 60, and 100 g/L salts, also with a H2/CO2 headspace. Acetate concentrations in the 20-, 60-, and 100 g/L media reached 8500, 3000, and 73 mg/L, respectively, after 150 days. Furthermore, methane production was only observed in one of the 20 g/L incubations. Results from 16S rRNA amplicon sequencing, targeted RNA-based qPCR and flow cytometry of environmental samples and enriched cultures will also be presented. Finally, we have begun testing the performance of selected homoacetogenic enrichment cultures in cathode-driven MES reactors.
Keywords
acetate, acetogenesis, saline, north sea, sediment, anaerobic, bioproduction

Citation

Please use this url to cite or link to this publication:

MLA
Arbour, Tyler. “Get Salty with Me : Acetate Production through Homoacetogenesis in (Hyper)Saline Conditions.” ISMET 7, International Society for Microbial Electrochemistry and Technology, 7th Global Conference, Abstracts, 2019.
APA
Arbour, T. (2019). Get salty with me : acetate production through homoacetogenesis in (hyper)saline conditions. In ISMET 7, International Society for Microbial Electrochemistry and Technology, 7th Global Conference, Abstracts. Okinawa, Japan.
Chicago author-date
Arbour, Tyler. 2019. “Get Salty with Me : Acetate Production through Homoacetogenesis in (Hyper)Saline Conditions.” In ISMET 7, International Society for Microbial Electrochemistry and Technology, 7th Global Conference, Abstracts.
Chicago author-date (all authors)
Arbour, Tyler. 2019. “Get Salty with Me : Acetate Production through Homoacetogenesis in (Hyper)Saline Conditions.” In ISMET 7, International Society for Microbial Electrochemistry and Technology, 7th Global Conference, Abstracts.
Vancouver
1.
Arbour T. Get salty with me : acetate production through homoacetogenesis in (hyper)saline conditions. In: ISMET 7, International Society for Microbial Electrochemistry and Technology, 7th Global Conference, Abstracts. 2019.
IEEE
[1]
T. Arbour, “Get salty with me : acetate production through homoacetogenesis in (hyper)saline conditions,” in ISMET 7, International Society for Microbial Electrochemistry and Technology, 7th Global Conference, Abstracts, Okinawa, Japan, 2019.
@inproceedings{8643183,
  abstract     = {Homoacetogenesis has become a hot topic, with industry interest, as a bio-process that can convert waste CO2 directly to a valorizable product (organic acids). However, the microorganisms catalyzing this reaction have remained little explored outside of their original discovery and later in the pioneering work on a few isolates in elucidation of the Wood-Ljungdahl pathway. We are exploring homoacetogenesis in saline environments for two main reasons: i) application in microbial electrosynthesis (MES) reactors under saline conditions, where salinity decreases ohmic resistance and inhibits competing methanogens by salt stress; and ii) fundamental microbiological interest. Motivating questions include: Can we find and enrich for novel salt-tolerant homoacetogens from un- or underexplored environments? Where is homoacetogenesis most active in the depth/redox profile of saline soil and sediment? We collected samples from North Atlantic coastal marine sediment (10 m.b.s.l.) and from high-altitude (3921 m.a.s.l.) shallow salt lakes of the Argentinian Andes. Serum-flask enrichments of North Sea samples in a homoacetogen seawater medium (35 g/L salinity) using a headspace of H2/CO2 (80/20 vol%) showed an initial period of acetate production (1-2 g/L in two weeks) from the top 10 cm of sediment, followed by a switch to methanogenesis. Samples collected from a salt lake in Argentina ranged in salinity from ~10 to 90 g/L total salts. We therefore explored the correlation between environmental salinity and acetate-production capacity in culture media of 20, 60, and 100 g/L salts, also with a H2/CO2 headspace. Acetate concentrations in the 20-, 60-, and 100 g/L media reached 8500, 3000, and 73 mg/L, respectively, after 150 days. Furthermore, methane production was only observed in one of the 20 g/L incubations. Results from 16S rRNA amplicon sequencing, targeted RNA-based qPCR and flow cytometry of environmental samples and enriched cultures will also be presented. Finally, we have begun testing the performance of selected homoacetogenic enrichment cultures in cathode-driven MES reactors.},
  author       = {Arbour, Tyler},
  booktitle    = {ISMET 7, International Society for Microbial Electrochemistry and Technology, 7th Global Conference, Abstracts},
  keywords     = {acetate,acetogenesis,saline,north sea,sediment,anaerobic,bioproduction},
  language     = {eng},
  location     = {Okinawa, Japan},
  title        = {Get salty with me : acetate production through homoacetogenesis in (hyper)saline conditions},
  url          = {https://www.ismet7.com/},
  year         = {2019},
}