Magnetite-mediated electrically connected community for shortening startup of methane-dependent denitrification in a membrane biofilm reactor

Concentration-dependent effects of nickel doping on activated carbon biocathodes

“…Improved electron transfer due to Ni addition may further explain the accelerated formate production observed here, as a decrease in lag phase has been previously shown for biological reactors supplemented with conductive materials. 75,77,78 While the effect of Ni on electrode conductivity and charge transfer resistance was not measured in this study, a positive correlation between dissolved Ni concentration and acetate production (Table 3) supports Please do not adjust margins Please do not adjust margins this mechanism of interaction between Ni and MES microorganisms, either due to improved electron transfer between the electrode and the biofilm, or due to the bio-crystalized Ni structures within the biofilm (Figure 8).…”

“…Several studies have previously exhibited a switch from H2-based to direct electron transfer in mixed microbial communities upon addition of conductive structures. 77,[79][80][81] This may offer an advantage, as direct electron transfer among species is considered to consume less energy, compared to the production and oxidation of H2. 76 In the presence of conductive materials, microbial cells likely do not need to spend energy for the production of electron-shuttling biological structures, such as membrane bound pili and cytochromes, as they can rely on the added conductive structures to facilitate electron transfer.…”

“…Therefore, higher electron recovery to acetate in Nicontaining reactors could be due to the higher abundance of these OTUs, compared to control MES reactors. Changes in microbial community composition within mixed cultures have also been previously shown as a response to the addition of conductive materials, including both metals 65,[74][75][76][77] and carbonaceous materials, [78][79][80] and have been correlated to altered community metabolism and increased production of methane. More specifically, within the field of MES for CO 2 conversion, Tian and co-workers modified a carbonaceous biocathode electrode with a H 2 -producing metal electrocatalyst, and report a decrease in the abundance within the biofilm of the electrotrophic Arcobacter, and an increase in the abundance of the hydrogenotrophic acetogen Acetobacterium, as a response to the addition of the metal catalyst.…”

Distinctive Microbial Processes and Controlling Factors Related to Indirect N2O Emission from Agricultural and Urban Rivers in Taihu Watershed

“…These methanogens were mixotrophic and included acetoclastic, hydrogenotrophic, and methylotrophic methanogens. , Methanosarcina barkeri is a model electroactive methanogen which can conduct extracellular electron transfer Methanospirillum hungatei can generate conductive filaments which allow it to conduct long-range electron transfer to other microorganisms . Hence, the significant positive correlation observed between methanogens and denitrifiers indicated there may be direct interspecies electron transfer (DIET) between methanogens and denitrifiers.…”

Micro–Nano Magnetite-Loaded Biochar Enhances Interspecies Electron Transfer and Viability of Functional Microorganisms in Anaerobic Digestion

“…Nano-sized magnetite (>50 nm) and micro-sized particles (<4.5 μm) were found to significantly promote methane yield, while inhibition of the methane production process happened with an increase in magnetite size due to the excessive aggregation possibility of large particles . The potential mechanism involved is considered that magnetite can facilitate DIET via substituting for c-type cytochromes and enrich the iron-reducing bacteria (IRB), which could exploit organic substrates as electron donors and decompose complex organic matters into small ones through dissimilatory iron reduction (DIR) . Though the genus Geobacter has been suggested to participate in DIET, it was not found in the AD system with the supplement of magnetite-loaded biochar. , The mechanism of how the magnetite-loaded biochar improves the methane yield remains unclear because the AD process involves various functional microbes.…”