在厌氧废水处理过程中混合微塑料(MPs)的存在已被证明通过抑制微生物活性来阻碍发酵性能。微生物电合成(MES),凭借其广泛的潜力,为耐火材料管理和甲烷回收提供了一个有前途的解决方案,通过增强微生物代谢和种间电子转移来实现。这项研究,因此,深入研究了MES在修复被混合MPs污染的废水中的功能影响和微生物对MES的反应。结果表明,混合MPs可以抑制甲烷产生(-52.38%)和物质去除(-26.59%),MES可以有效减轻这种抑制作用(-22.86%,-19.01%)。同时,MES还促进了对电子转移至关重要的酶活性,如细胞色素C和烟酰胺腺嘌呤二核苷酸(NADH),以及与能量代谢相关的三磷酸腺苷(ATP)。此外,MES增强了微生物对混合MPs的抵抗力,胞外聚合物(EPS)的增加证明了这一点,尽管活性氧(ROS)的产生和乳酸脱氢酶(LDH)的释放略有增加。相应地,电刺激促进了与发酵相关的功能性微生物的富集,醋酸盐生产,产电,和产甲烷,并刺激与甲烷代谢相关的基因表达水平升高。值得注意的是,甲烷介导的乙酰碎屑途径成为主要的产甲烷途径,由甲烷杆菌驱动的氢营养途径成功。最后,该研究强调了施加电压和载体在能量代谢和物质运输中的支持作用,与产甲烷有关。总的来说,MES在减轻由混合MPs暴露引起的生物毒性以及增强厌氧废水处理和甲烷回收方面表现出功效。
The presence of mixed microplastics (MPs) in anaerobic wastewater treatment processes has been shown to impede fermentation performance by suppressing microbial activity. Microbial electrosynthesis (MES), with its extensive potential, offers a promising solution for refractory substances management and methane recovery, achieved through the enhancement of microbial metabolism and interspecies electron transfer. This study, therefore, delves into the functional impacts and the microbial response to MES in the remediation of wastewater contaminated with mixed-MPs. Results indicated that mixed-MPs could inhibit methane production (-52.38%) and substance removal (-26.59%), and MES could effectively mitigate this inhibitory effect (-22.86%, -19.01%). Concurrently, MES also boosts enzymatic activities pivotal for electron transfer, such as cytochrome c and nicotinamide adenine dinucleotide (NADH), as well as those linked to energy metabolism like adenosine triphosphate (ATP). Furthermore, MES bolsters microbial resistance to mixed-MPs, as evidenced by an increase in extracellular polymeric substances (EPS), albeit with a minor rise in reactive oxygen species (ROS) production and lactate dehydrogenase (LDH) release. Correspondingly, electric stimulation promoted the enrichment of functional microorganisms associated with fermentation, acetate production, electrogenesis, and methanogenesis, and stimulated elevated expression levels of genes related to methane metabolism. Notably, the Methanothrix-mediated acetoclastic pathway emerges as the predominant methanogenic route, succeeded by the Methanobacterium-driven hydrogenotrophic pathway. Lastly, the study underscores the supportive role of applied voltage and carriers in energy metabolism and substance transport, which are associated with methanogenesis. Overall, MES demonstrates efficacy in mitigating the biotoxicity induced by mixed-MPs exposure and in enhancing anaerobic wastewater treatment and methane recovery.