Co-oxidation of arxB response by As(III), Fe(II), and Mn(II)-oxidizing bacteria in As-contaminated tap water.

Iron pipe corrosion can be caused by tap water contamination with arsenic (As), heavy metals, and symbiotic microorganisms. In this study, we performed laboratory experiments on drinking water samples collected from Yanbian University of Science and Technology, Jilin Province, eastern China, to evaluate the mechanism of heavy metal oxidation by microbes. The experiments revealed corrosion of the entire water pipe, heavy metal contamination, and microbial co-oxidation of As(III), iron (Fe(II)), and manganese (Mn(II)). Pipe corrosion was observed in several university buildings, with particularly high levels of As (4.3 μg/L), Fe (143.4 μg/L), Mn (0.6 μg/L), and bacteria (1,200 CFU/100 mL) in the Engineering building. The As(III), Fe(II), and Mn(II) co-oxidation activity of As(III)-resistant and Fe(II)- and Mn(II)-oxidizing bacteria was investigated based on frvA, aioE, boxA, arsB, and arxB gene activities in Burkholderia glathei strain YUST-DW12 (NCBI accession No.: HM640291). Batch experiments revealed that YUST-DW12 completely co-oxidized 1 mM As(III) to As(V), 5 mM Fe(II) to Fe(III), and 5 mM Mn(II) to Mn(IV) within 45-50 h, 10 h, and 25 h, respectively. Co-oxidation related to arxB gene activity significantly contributed to As, Fe, and Mn bioremediation and mobility in tap water, indicating that As, Fe, and Mn oxidases in bacteria control the biogeochemical cycle of contaminated public tap water affected by iron pipe corrosion. This research provides novel insights into the role of microbial arxB in As(III), Fe(II), and Mn(II) co-oxidation in corroded iron pipes, enhancing our understanding of the co-oxidative removal of As from contaminated tap and bottled water.