Environmental implications of bacterial-derived extracellular reactive oxygen species

The extracellular reactive oxygen species (eROS) generation, a biochemical process commonly conserved across diverse bacteria, fundamentally results in previously unconsidered but significant contributions to the natural ROS pool. Bacteria that typically conduct light-independent oxygen respiration generate and release superoxide into the environment, thereafter facilitating more highly-oxidative ROS production through a series of physiochemical reaction chains. Based on that, the eROS significantly accomplishes metabolic interactions of bacteria with their surrounding environment. As such, it is about time to advance our mechanistic understanding of eROS-generation bacterial behaviors and the associated environmental implications. This review demonstrates late discoveries on the microbial metabolisms of how bacteria function in the process of eROS generation and highlights the critical environmental relevance of bacterial-derived eROS regarding the cycling of biogeochemical elements, the transformation of organic matter, and the regulation of antibiotic resistance genes. This review also appeals for more attention on the development of reliable detecting methodologies for eROS and expanding borders of microbial effects on our Earth from an interdisciplinary view.