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Sun R, Fu M, Ma L, Zhou Y, Li Q. Iron reduction in composting environment synergized with quinone redox cycling drives humification and free radical production from humic substances. BIORESOURCE TECHNOLOGY 2023:129341. [PMID: 37343801 DOI: 10.1016/j.biortech.2023.129341] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 06/23/2023]
Abstract
The aim of this paper was to investigate the influence of Fe (III) on humification and free radicals evolution. The experimental data showed that the experimental group (CT) with Fe2(SO4)3 had a better degree of humification than the control group (CK). The humic substances (HS) content was 10% higher in CT (23.94 mg·g-1) than in CK (21.54 mg·g-1) in the final. Fe (III) contributed significantly to the formation of free radicals in HS. The amount of H2O2 in CT increased to 74.8 mmol·kg-1, while CK was only 46.5 mmol·kg-1. The content of semiquinone free radical was 10.32×1011 spins/mm3 in CT, 5.11×1011 spins/mm3 in CK in the end. Several iron-reducing bacteria were detected in composting, among which Paenibacillus was dominant. The above findings suggested that the application of Fe2(SO4)3 enhanced the iron reduction synergistic quinone redox cycling and promoted the generation of free radicals during the humification of composting.
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Affiliation(s)
- Ru Sun
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Mengxin Fu
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Liangcai Ma
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Yucheng Zhou
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Qunliang Li
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China.
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Lieke T, Steinberg CEW, Meinelt T, Knopf K, Kloas W. Modification of the chemically induced inflammation assay reveals the Janus face of a phenol rich fulvic acid. Sci Rep 2022; 12:5886. [PMID: 35393468 PMCID: PMC8991211 DOI: 10.1038/s41598-022-09782-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 03/28/2022] [Indexed: 11/09/2022] Open
Abstract
Inflammation is an essential process as a reaction towards infections or wounding. Exposure to hazardous environmental pollutants can lead to chronic inflammations, where the resolving phase is delayed or blocked. Very contradictory studies have been reported on the pro- and anti-inflammatory effects of humic substances (HSs) leading to significant disagreements between researchers. To a certain extent, this can be attributed to the chemical heterogeneity of this group of xenobiotics. Here we show for the first time that pro- and anti-inflammatory effects can occur by one HSs. We adapted an assay that uses green fluorescence-labeled zebrafish larvae and CuSO4 to indue an inflammation. In wild-type larvae, exposure to 50 µM CuSO4 for 2 h activated the production of reactive oxygen species, which can be monitored with a fluorescence dye (H2DCFDA) and a microplate reader. This allows not only the use of wild-type fish but also a temporal separation of copper exposure and inflammatory substance while retaining the high throughput. This modified assay was then used to evaluate the inflammatory properties of a fulvic acid (FA). We found, that the aromatic structure of the FA protects from inflammation at 5 and 50 mg C/L, while the persistent free radicals enhance the copper-induced inflammation at ≥ 300 mg C/L.
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Affiliation(s)
- Thora Lieke
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, 12587, Berlin, Germany. .,Faculty of Life Sciences, Humboldt University of Berlin, 10115, Berlin, Germany.
| | - Christian E W Steinberg
- Faculty of Life Sciences, Humboldt University of Berlin, 10115, Berlin, Germany.,Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, China
| | - Thomas Meinelt
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, 12587, Berlin, Germany
| | - Klaus Knopf
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, 12587, Berlin, Germany.,Faculty of Life Sciences, Humboldt University of Berlin, 10115, Berlin, Germany
| | - Werner Kloas
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, 12587, Berlin, Germany.,Faculty of Life Sciences, Humboldt University of Berlin, 10115, Berlin, Germany
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