The role and related microbial processes of Mn-dependent anaerobic methane oxidation in reducing methane emissions from constructed wetland-microbial fuel cell

Recent advances in constructed wetlands methane reduction: Mechanisms and methods

“…CH 4 emissions in CW-MFC systems are also driven by substrate type. A Mn CW-MFC system was shown to generate lower CH 4 emissions (53.44-66.64 mg/m 2 /h) than a clinopyrite CW-MFC system (62.69-88.02 mg/m 2 /h; Zhang et al, 2021b). Furthermore, Xu et al (2021b) observed a 25.42% reduction in average CH 4 emissions from Mn-based reactors compared to graphite granule-based reactors.…”

“…Highly crystalline iron oxides and manganese oxides are electron-exchange substrates that are abundant and readily available, making them highly suitable for use as CW substrate materials (Zhang et al, 2021b;Yu et al, 2022). Cheng et al (2021a) reported that CWs using iron oxide substrates emitted less CH 4 , finding that iron oxide increased CH 4 emissions by promoting electron transfer between Geobacter and methanogens, while also directly inhibiting the activity of methanogens and some enzymes involved in CO 2 reduction, and promoting the AOM process under the influence of dissimilated metal-reducing bacteria, ultimately resulting in a reduction in CH 4 emissions overall (Cheng et al, 2021b).…”

“…Furthermore, Xu et al (2021b) observed a 25.42% reduction in average CH 4 emissions from Mn-based reactors compared to graphite granule-based reactors. This may be due to the occurrence of Mn-driven Mn-AOM lowering CH 4 emissions, while dissimilatory metal reduction processes encourage competition between EABs and methanogens, as well as increasing the growth of EABs on Mn ore anodes, further inhibiting the growth of methanogens (Li et al, 2019;Zhang et al, 2021bZhang et al, , 2022. Therefore, different substrate materials have varying electron acceptor functions and significantly affect CH 4 emissions, with Mn exhibiting high prospects as a substrate for CH 4 emissions reduction.…”

“…Average CH 4 emissions are extremely variable by reviewing 158 studies data, ranging from 0.15 to 5,220 mg/ m 2 /h, which can disrupt earth radiation levels (Mander et al, 2014) It has been reported that a 1-fold increase in atmospheric CH 4 concentration would lead to tropospheric surface warming by 0.2-0.3 degrees, presenting a serious risk to human and environmental health (Dreyfus et al, 2022). CH 4 emissions originate from both anthropogenic and natural sources, with wetland ecosystems being the largest natural source, generating annual global CH 4 emissions of 177-284 Tg (Zhang et al, 2021b), 82% of which originate from CWs worldwide (Nuamah et al, 2020). CH 4 has become an important aspect of global carbon reduction, due to its potentially considerable role in future warming.…”

TiO2/CdS composite photocathode improves the performance and degradation of wastewater in microbial fuel cells

“…In the microbial fuel cells (MFCs) with photoelectrodes, organic substances (such as acetate) are oxidized by the electricity‐generating microorganisms in the anode chamber. The electrons released to the anode are transferred to the cathode by the external circuit and then combine with an electron acceptor to form water 13–17 . Meanwhile, the process in which photo‐generated holes are left as electron acceptors and combined with electrons transferred from the anode increases the reaction rate of the cathode 18 .…”