Microplastics (MPs) and Perfluorooctane sulfonate (PFOS) are two hard-biodegradable pollutants widely existing in the waste streams treated by anaerobic digestion. However, their synergistic effect on methanogenic metabolism is still unknown. This study investigated the impact of polyethylene terephthalate (PET) MPs alone and co-existing with PFOS on CO₂ conversion to CH₄ in a thermophilic biogas upgrading system. The results showed that either PET MPs addition alone or coexisting with PFOS improved the ultimate CH₄ percentage and increased CO₂ utilization rate. When Fe⁰ was added into the reactors with PET to enhance the interspecies electron transfer, a potential defluorination was observed with a defluorination rate of 15.88 ± 1.53%. Exposure of the reactor to PFOS of 300 μg/L could change the methanogenic pathway, resulting in a newly emerged Methanomassiliicoccus with dominance of 16%. Furthermore, under the exposure of PFOS, the number of predicted genes regulating enzymes in methanogenic steps from CO₂ increased. These results suggest that the co-existence of PET MPs and PFOS will not inhibit the activity of hydrotrophic methanogenes, and a portion of PFOS may be biodegraded during the methanogenesis under Fe⁰ regulation.

微塑料 （MP） 和全氟辛烷磺酸盐 （PFOS） 是两种难以生物降解的污染物，广泛存在于厌氧消化处理的废物流中。然而，它们对产甲烷代谢的协同作用仍然未知。本研究调查了聚对苯二甲酸乙二醇酯 （PET） MP 单独以及与 PFOS 共存对嗜热沼气提质系统中 CO 2 转化为 CH 4 的影响。结果表明，单独添加 PET MPS 或与 PFOS 共存都提高了最终 CH₄ 百分比并提高了 CO₂ 利用率。当 Fe⁰ 加入 PET 反应器以增强物种间电子转移时，观察到潜在的脱氟反应，脱氟速率为 15.88 ± 1.53%。反应器暴露于 300 μg/L 的 PFOS 可能会改变产甲烷途径，导致新出现的甲烷肿块球菌，占主导地位为 16%。此外，在 PFOS 暴露下，预测的 CO 2 产甲烷步骤中调节酶的基因数量增加。这些结果表明，PET MPs 和 PFOS 的共存不会抑制水养产甲烷的活性，并且在 Fe 0 调节下，一部分 PFOS 可能在甲烷生成过程中被生物降解。