State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; Forest Product Biotechnology, Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada.
Forest Product Biotechnology, Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada; Advanced Renewable Materials Lab, Department of Wood Science, University of British Columbia, 2424 main mall, Vancouver V6T 1N4, Canada.
Sci Total Environ. 2024 Nov 15;951:175814. doi: 10.1016/j.scitotenv.2024.175814. Epub 2024 Aug 26.
Anaerobic digestion provides a solution to the inefficient use of carbon resources caused by improper disposal of corn stover-based ethanol stillage (CES). In this regard, we developed a single-chamber anaerobic digestion integrated microbial electrolysis cells system (AD-MEC) to convert CES into biogas while simultaneously upgrading biogas in-situ by employing voltages ranging from 0 to 2.5 V. Our results demonstrated that applying 1.0 V increased the CH yield by 55 % and upgraded the CH content in-situ to 82 %. This voltage also promoted the well-formed biofilm on the electrodes, resulting in a 20-fold increase in current. However, inhibition was observed at high voltages (1.5-2.5 V), suppressing syntrophic organic acid-oxidizing bacteria (SOB). The dissociation between SOB and methanogens led to accumulation of propionic and butyric acid, which, in turn, inhibited methanogens. The degradation of CES was accelerated by unclassified_o_norank_c_Desulfuromonadia on the anode, likely leading to an increase in mixotrophic methanogenesis due to the synergistic interaction among Aminobacterium, Sedimentibacter, and Methanosarcina. Furthermore, the enrichment of electroactive bacteria (EB) such as Enterococcus and Desulfomicrobium likely facilitates direct interspecies electron transfer to Methanobacterium, thereby promoting the conversion of CO to CH through hydrogenotrophic methanogenesis. Rather than initially stimulating the EB in the bulk solution to accelerate the start-up process of AD, our study revealed that applying mild voltage up to 1.0 V tended to mitigate the negative impact on the original microorganisms, as it gradually enriched EB on the electrode, thereby enhancing biogas production.
厌氧消化为解决玉米秸秆乙醇糟（CES）不当处理导致的碳资源利用效率低下问题提供了一种解决方案。在这方面，我们开发了一种单室厌氧消化集成微生物电解池系统（AD-MEC），在 0 到 2.5 V 的电压范围内将 CES 转化为沼气，同时原位提升沼气。我们的结果表明，施加 1.0 V 可将 CH 产率提高 55%，并将 CH 含量原位提升至 82%。该电压还促进了电极上形成良好的生物膜，从而使电流增加了 20 倍。然而，在高电压（1.5-2.5 V）下观察到抑制作用，抑制了同型有机酸盐氧化菌（SOB）。SOB 与产甲烷菌的分离导致丙酸和丁酸的积累，从而抑制了产甲烷菌。CES 的降解被阳极上未分类的_o_norank_c_脱硫单胞菌加速，可能由于 Aminobacterium、Sedimentibacter 和 Methanosarcina 之间的协同作用，导致混合营养型产甲烷作用增加。此外，电活性细菌（EB）如肠球菌和脱硫微菌的富集可能有助于直接的种间电子转移到 Methanobacterium，从而通过氢营养型产甲烷作用促进 CO 向 CH 的转化。与最初刺激 bulk 溶液中的 EB 以加速 AD 的启动过程不同，我们的研究表明，施加温和的电压（高达 1.0 V）有助于减轻对原始微生物的负面影响，因为它逐渐在电极上富集 EB，从而提高沼气产量。
