Biological conversion of carbon dioxide (CO₂) to methane (CH₄) through the exogenous addition of hydrogen (H₂) represent a promising biotechnology for biogas upgrading and energy conversion through the process of H₂-mediated biomethanation. Acetate accumulation has however been observed during H₂ addition, which may deteriorate process stability. Using ¹³C-isotope techniques, we found that acetate consumption declined by 84% upon H₂ addition in digestate from lab-scale digesters treating agricultural waste products (AD-Manure) but did not decline in digestate based on wastewater treatment sludge (AD-WWT). Dominance of different acetoclastic methanogens, along with the fact that the H₂-sensitive process of syntrophic acetate oxidation (SAO) was responsible for converting 27% of the acetate in AD-Manure and only 4% in AD-WWT, could explain the different response of AD-Manure and AD-WWT. Our results improve the understanding of acetate consumption rates during H₂ addition in reactors treating different organic feedstock, and how these are suited for H₂-mediated biomethanation.

通过氢（H ₂）的外源添加将二氧化碳（CO ₂）生物转化为甲烷（CH ₄）代表了一种有前途的生物技术，可用于通过H ₂介导的生物甲烷化工艺进行沼气提纯和能量转换。但是，在添加H _2的过程中观察到了乙酸盐的积累，这可能会降低工艺的稳定性。使用¹³ C同位素技术，我们发现H ₂消耗的乙酸盐减少了84％从实验室规模的处理农业废物产品的消化池中添加消化物（AD-Manure），但基于废水处理污泥的消化物（AD-WWT）并未下降。不同的破乳产甲烷菌的优势地位，以及对H ₂敏感的乙酸突触氧化过程（SAO）负责AD-Manure中27％的乙酸盐转化和AD-WWT中仅4％的乙酸转化率这一事实，可以解释这一不同之处。 AD-Manure和AD-WWT的响应。我们的结果增进了对在处理不同有机原料的反应器中添加H ₂期间乙酸盐消耗速率的理解，以及它们如何适用于H ₂介导的生物甲烷化。