Microbial community mediates hydroxyl radical production in soil slurries by iron redox transformation. (15th July 2022)

• Record Type: Journal Article
• Authors: Wan, Dan; Liu, Fei-Fei; Chen, Jiu-Bin; Kappler, Andreas; Kuzyakov, Yakov; Liu, Cong-Qiang; Yu, Guang-Hui
• Is Part Of: Water research. Volume 220(2022)
• Publication Date: 2022-07-15
• Subjects: Fenton reaction -- Iron minerals -- Microorganism-mineral interactions -- Reactive oxygen species -- Synergistic effect; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2022.118689
• Languages: English
• ISSNs: 0043-1354

Abstract

Highlights: Microbial controlling HO production at soil-water interfaces was studied. Microbial communities drive HO generation mainly via Fe redox cycling. K82, Geobacter, Paucimonas and Desulfotomaculum are key genera for HO production. The discrepancies of genera well interpreted the HO production in soil slurries. Abstract: The generation of reactive oxygen species (ROS) mediated by minerals and/or microorganisms plays a vital but underappreciated role in affecting carbon and nutrient cycles at soil-water interfaces. It is currently unknown which interactions between microbial communities and iron (Fe) minerals produce hydroxyl radical (HO ), which is the strongest oxidant among ROS. Using a series of well-controlled anoxic incubations of soil slurries, we demonstrated that interactions between microbial communities and Fe minerals synergistically drove HO production (up to ∼100 nM after 21-day incubation). Microorganisms drove HO generation in anoxic environments predominantly by modulating iron redox transformation that was more prominent than direct production of ROS by microorganisms. Among the microbial communities, Geobacter, Paucimonas, Rhodocyclaceae_K82, and Desulfotomaculum were the key genera strongly affecting HO production. In manured soils, the former two species had higher abundances and were crucial for HO production. In contrast, the latter two species were mainly abundant and important in soils with mineral fertilizers. Our study suggests that abundant highly reactive oxidant HO can be generated in anoxic environments and the microbial community-mediated redox transformations of iron (oxyhydr)oxides may be responsible for the HO production. These findings shed light on the microbial generation of HO in fluctuating redox environments and on consequences for global C and nutrient cycling. Graphical abstract: Image, graphical abstract