Electricity production from carbon monoxide and synthesis gas in a microbial fuel cell
Bibliographic record
Abstract
Synthesis gas (syngas), which primarily consists of carbon monoxide (CO) and hydrogen (H2), is a versatile energy carrier that can be converted to gaseous and liquid fuels or can be used for electricity production. This study was focused on MFC design improvements for performance enhancement on CO/syngas and elucidation of microbial communities, and biotransformation pathways involved in electricity production from CO/syngas in an MFC. One of the primary challenges for an efficient bioconversion of CO and syngas is the low solubility of these gaseous substrates in the aqueous phase. The first study of this thesis demonstrated the applicability of silicone membrane systems for improved CO transfer into the anodic liquid of MFCs. The incorporation of flat silicone membrane and thin wall silicone tubing into the anodic chamber of CO-fed MFCs led to improved CO transformation efficiency and correspondingly improved MFC performance. A CO transformation efficiency of 77 % and maximum power output of 18 mW/L (normalized to anodic compartment volume) was achieved for silicone membrane installed MFC. A comparably higher CO transformation efficiency of 98 % was obtained for silicone tubing installed MFC, but the high dissolved CO concentrations in the anodic liquid partially inhibited the microbial activity, thereby lowering the maximum power output to 13 mW/L. Efficient gas transfer also allowed for focusing on the process microbiology. The microbial communities and biotransformation pathways prevalent in two mesophilic CO-fed MFCs were elucidated in the second study. The identification of the microorganisms belonging to the genera Geobacter, Desulfovibrio, and Clostridium, along with the detection of acetate as the primary metabolic product in both MFCs; affirmed our hypothesis that electricity production from CO/syngas in a mesophilic MFC is primarily accomplished by a two-step process, where CO/syngas is first converted to acetate by homo-acetogenic and carboxdotrophic microorganisms, and the acetate is then utilized by CO-tolerant acetate oxidizing electricigenic microorganisms. The bioconversion of CO/syngas to electricity in an MFC was also tested at thermophilic temperature of 50°C. Silicone tubing was used for syngas delivery and the anodic design was improved to increase the microbial density. An improved volumetric power output of 33-35 mW/L and syngas conversion efficiency of 87-98 % was achieved. Also an improved Coulombic efficiency (CE) of 26 % was obtained. The analysis of the anodic microbial communities and metabolic products, along with single substrate tests where MFC was operated solely on CO or H2, revealed that similar to mesophilic MFCs electricity generation from syngas at thermophilic temperatures also occurred through syngas conversion to acetate followed by its oxidation by CO-tolerant electricigenic microorganisms. In the final study of this thesis, the applicability of a multi-electrode design containing three anodes and two cathodes to achieve high volumetric power output and CE on syngas was evaluated at several operating temperatures ranging from 37°C to 50°C. Also, the impact of different anode-cathode arrangements on power output was examined. The multi-electrode configuration considerably enhanced the system performance and provided a compact system design which could have major economic and operational implications for large scale syngas-fed MFC systems. A maximum power density of 33 mW/L and CE of 43 % was achieved at an operating temperature of 37°C. The MFC power density was greatly impacted by the anode-cathode arrangement and the highest power density was achieved in a three anode-two cathode (3A-2C) arrangement.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".