1. Production of extracellular superoxide radical in microorganisms and its environmental implications: A review.
- Author
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He, Zhanfei, Li, Qunqun, Xu, Yao, Zhang, Daoyong, and Pan, Xiangliang
- Subjects
POLLUTANTS ,RADICALS (Chemistry) ,EMERGING contaminants ,HEAVY metals ,NADPH oxidase ,NICOTINAMIDE adenine dinucleotide phosphate ,SUPEROXIDES - Abstract
Extracellular superoxide radical (O 2
•− ) is ubiquitous in microbial environments and has significant implications for pollutant transformation. Microbial extracellular O 2•− can be produced through multiple pathways, including electron leakage from the respiratory electron transport chain (ETC), NADPH oxidation by the transmembrane NADPH oxidase (NOX), and extracellular reactions. Extracellular O 2•− significantly influences the geochemical processes of various substances, including toxic metals and refractory organic pollutants. On one hand, extracellular O 2•− can react with variable-valence metals and detoxify certain highly toxic metals, such as As(III), Cr(VI), and Hg(II). On the other hand, extracellular O 2•− can directly or indirectly (via Bio-Fenton) degrade many organic pollutants, including a variety of emerging contaminants. In this work, we summarize the production mechanisms of microbial extracellular O 2•− , review its roles in the transformation of environmental pollutants, and discuss the potential applications, limiting factors, and future research directions in this field. [Display omitted] • ETC and NOX are the main production pathways of microbial extracellular O 2•− . • Environmental stresses usually increase the levels of microbial extracellular O 2•− . • Extracellular O 2•− can oxidize or reduce variable metals (Fe, Mn, Cr, Ag, Sb, etc.). • Extracellular O 2•− can degrade refractory organic pollutants (plastics, PPCPs, etc.). [ABSTRACT FROM AUTHOR]- Published
- 2023
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