Biogenic iron sulfide functioning as electron-mediating interface to accelerate dissimilatory ferrihydrite reduction by Shewanella oneidensis MR-1

Kinetics of Hydroxyl Radical Production from Oxygenation of Reduced Iron Minerals and Their Reactivity with Trichloroethene: Effects of Iron Amounts, Iron Species, and Sulfate Reducing Bacteria

“…Fe­(II)-containing minerals are widely observed in sediments collected from subsurface aquifers, ,, a floodplain adjacent to the Yangtze River, the Pearl River watershed, and tundra near Toolik Lake . Ferrous iron in these sediments has been associated with individual RIM, including mackinawite, siderite, , ankerite, biotite, , montmorillonite, chlorite, , and illite, , and has been linked to the presence of dissimilatory iron and sulfate reducing bacteria that promote Fe­(III)-(oxyhydr)­oxide mineral and aqueous sulfate reduction. , Anoxic sediments containing RIM can become exposed to O 2 and produce reactive oxygen species. The former can occur, for example, due to temporal and spatial fluctuations of the groundwater table driven by hydrological dynamics (e.g., injection or extraction of groundwater, , precipitation or drought conditions, rising and falling levels of rivers connected to aquifers , ), flooding or drying in agricultural fields, and thermocline disruptions in surface waters .…”

“…For example, S(-II) reaction with Fe(III) was performed in aqueous solutions at circumneutral pH (eq 1) and Fe(III) was provided as iron (oxyhydr)oxide minerals; in all experiments, S(0) was the dominant product. 54,63 , SO 4 2− , and SO 3 2− (with good mass balance) were the dominant products, 40 while in another polysulfides, S(0), and S 2 O 3 2− were produced in varying amounts depending on pH and sulfur to oxygen ratios. 53 When S(-II) was reacted with •OH produced from ultrasonic irradiation, 64 .…”

“…Reduced iron species like mackinawite (FeS) and pyrite (FeS 2 ) are frequently observed in subsurface anoxic environments. , They precipitate from the reaction of ferrous iron with sulfide, in some cases, coupled with dissimilatory bacterial reduction of sulfate and/or ferric oxide . Anoxic subsurface environments can be perturbed by groundwater recharge or drawdown, active groundwater pumping, surface-water groundwater interactions, and groundwater remediation, − which can introduce O 2 and provide fresh oxic-anoxic interfaces known for high reactivity. , As recently reported, the oxygenation of ferrous minerals, including mackinawite, can produce several reactive oxygen species (ROS) via a series of single-electron transfer reactions, ,− and these are superoxide anions (O 2 •– ), hydrogen peroxide (H 2 O 2 ), and hydroxyl radicals (•OH).…”

Interspecific Electron Transfer-Driven Oxytetracycline Degradation by Autotrophic Coculture of Sulfur-Oxidizing and Sulfate-Reducing Bacteria

“…Therefore, compared to Chem FeS, bio-FeS stimulated c -Cyts-DIET secretion more strongly. At the same time, bio-FeS could be more tightly and evenly wrapped on the SRB surface to achieve a better biotic/abiotic interfacial coupling effect. , Therefore, a more efficient IET pathway was formed at the biotic/abiotic interface of SRB and SOB, coupled with intracellular energy production, extracellular membrane metabolism, and IET, which jointly accelerated the biodegradation process of OTC.…”

Biogenic FeS nanoparticles modulate the extracellular electron transfer and schwertmannite transformation

“…9 Moreover, a record-high interfacial electron-transfer efficiency was achieved with a conductive layer and cross cell membrane of individual S. oneidensis MR-1. 11 Recently, Zhu et al 12 confirmed that the in situ formed FeS NPs secondary minerals could mediate and accelerate interfacial electron transfer from S. oneidensis MR-1 to ferrihydrite through interfacing with the bacterial EET routes. Inspiringly, this promotion of FeS NPs is cross-species.…”