Abstract
This study aimed to systematically investigate the effect of elevated hydrogen partial pressure on mixed culture homoacetogenesis in the range of 1–25 bar. Seven batch experiments were performed at different initial headspace pressures, i.e., 1, 3, 5, 10, 15, 20, and 25 bar. The 15 bar batch showed the highest gas uptake rate (6.22 mol h−1L−1) and volatile fatty acids synthesis (3.55 g L−1) by a final microbial consortium that was found to be largely reduced in complexity compared to the original inoculum culture and dominated by members of the Pseudomonadaceae and Clostridiaceae. Product distribution shifted from acetate to C3-C5 acids at a pressure above 15 bar. 15 bar was found to be the optimum elevated pressure for the used mixed culture fermentation medium and biodiversity used in this study, and pressure above 15 bar inhibited the microbial consortia and resulted in lowered gas uptake rate and product synthesis.
Highlights
Syngas is a key product of biomass pyrolysis and gasification processes, contains carbon monoxide (CO), hydrogen (H2) and carbon dioxide (CO2) (Grimalt-Alemany et al, 2018)
Homoacetogens are a group of acetogenic bacteria that have the capability to ferment syngas into acids and alcohols (Mohammadi et al, 2011)
The impact of elevated pressure could be the reason for such instant pressure reduction; according to equation (2), the increase pressure-gradient, increase the H2 molar transfer rate that results in the headspace pressure reduction
Summary
Syngas is a key product of biomass pyrolysis and gasification processes, contains carbon monoxide (CO), hydrogen (H2) and carbon dioxide (CO2) (Grimalt-Alemany et al, 2018). It can be converted to biofuels through bacteria-mediated acidogenesis, solventogenesis, and methanogenesis or thermochemical processes like Fischer-Tropsch (Daniell et al, 2012). Acetate is the most common metabolic intermediate, further converted to biogas in an anaerobic digestor (Anukam et al, 2019; Geppert et al, 2016). Biogas production from syngas is a sustainable approach in the field of clean biofuel production (Torri et al, 2020). Utilizing syngas to produce biofuels brings sustainable value addition (Daniell et al, 2012) and reduces the alternative cost of carbon capture and storage. Fischer et al (1932) first reported that the homoacetogens with capabilities to use CO2 and H2 as carbon and energy sources, respectively, to produce acetate (Drake, 2012), Equation (1).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
