BES biogas upgrading studies have typically used bicarbonate or commercial gas mixtures as a biocathode substrate instead of anaerobic digester biogas. Therefore, the objective of this study was to (i) compare the performance of a methanogenic BES between CO₂-fed and biogas-fed cycles; (ii) investigate possible factors that may account for observed performance differences; and (iii) assess the performance of a biogas-fed biocathode at various applied cathode potentials. The maximum 1-d CH₄ production rate in a biogas-fed biocathode (3003 mmol/m²-d) was 350% higher than in a CO₂-fed biocathode (666 mmol/m²-d), and the biogas-fed biocathode was capable of maintaining high performance despite a variable biogas feed composition. Anode oxidation of reduced gases (e.g., CH₄ and H₂S) from biogas may theoretically contribute 4% to 35% of the total charge transfer from anode to cathode at applied cathode potentials of −0.80 to −0.55 V (vs SHE). The introduction of biogas did not significantly change the biocathode archaeal community (dominated by a Methanobrevibacter sp. phylotype), but the bacterial community shifted away from Bacteroidetes and toward Proteobacteria, which may have contributed to the improved performance of the biogas-fed system. This study shows that anaerobic digester biogas is a promising biocathode feedstock for BES biogas upgrading.

中文翻译：

---

二氧化碳与厌氧消化沼气作为产甲烷生物阴极原料的比较。

BES沼气升级研究通常使用碳酸氢盐或商用气体混合物作为生物阴极底物，而不是厌氧消化池沼气。因此，本研究的目的是（i）比较在CO ₂喂养和沼气喂养循环之间产甲烷的BES的性能；（ii）研究可能导致观察到的性能差异的可能因素；（iii）在各种施加的阴极电势下评估沼气供入的生物阴极的性能。沼气喂养的生物阴极（3003 mmol / m ² -d）的最大1-d CH ₄生产率比CO ₂喂养的生物阴极（666 mmol / m ²）高350％-d），并且尽管沼气进料组成可变，但沼气供给的生物阴极仍能够保持高性能。从生物气中还原的气体（例如CH ₄和H ₂ S）的阳极氧化理论上可在-0.80至-0.55 V（vs SHE）施加的阴极电势下贡献从阳极到阴极的总电荷转移的4％至35％。沼气的引入并没有显着改变生物阴极古细菌群落（以Methanobrevibacter sp。系统型为主），但细菌群落从拟杆菌转变为变形杆菌。，这可能有助于改善沼气喂养系统的性能。这项研究表明，厌氧消化池沼气是用于BES沼气升级的有前途的生物阴极原料。