Arsenic Removal via the Biomineralization of Iron-Oxidizing Bacteria Pseudarthrobacter sp. Fe7

Abstract

Arsenic (As) is a highly toxic metalloid, and its widespread contamination of water is a serious threat to human health. This study explored As removal using Fe(II)-oxidizing bacteria. The strain Fe7 isolated from iron mine soil was classified as the genus Pseudarthrobacter based on 16S rRNA gene sequence similarities and phylogenetic analyses. The strain Fe7 was identified as a strain of Gram-positive, rod-shaped, aerobic bacteria that can oxidize Fe(II) and produce iron mineral precipitates. X-ray diffraction, X-ray photoelectron spectroscopy, and energy-dispersive X-ray spectroscopy patterns showed that the iron mineral precipitates with poor crystallinity consisted of Fe(III) and numerous biological impurities. In the co-cultivation of the strain Fe7 with arsenite (As(III)), 100% of the total Fe and 99.9% of the total As were removed after 72 h. During the co-cultivation of the strain Fe7 with arsenate (As(V)), 98.4% of the total Fe and 96.9% of the total As were removed after 72 h. Additionally, the iron precipitates produced by the strain Fe7 removed 100% of the total As after 3 h in both the As(III) and As(V) pollution systems. Furthermore, enzyme activity experiments revealed that the strain Fe7 oxidized Fe(II) by producing extracellular enzymes. When 2% (v/v) extracellular enzyme liquid of the strain Fe7 was added to the As(III) or As(V) pollution system, the total As removal rates were 98.6% and 99.4%, respectively, after 2 h, which increased to 100% when 5% (v/v) and 10% (v/v) extracellular enzyme liquid of the strain Fe7 were, respectively, added to the As(III) and As(V) pollution systems. Therefore, iron biomineralized using a co-culture of the strain Fe7 and As, iron precipitates produced by the strain Fe7, and the extracellular enzymes of the strain Fe7 could remove As(III) and As(V) efficiently. This study provides new insights and strategies for the efficient remediation of arsenic pollution in aquatic environments.

16S rRNA sequencing and Targeted Metabolomics Analyses Reveal Rhizosphere Microbial Diversity and Flavonoids Dynamics in Scutellaria baicalensis Georgi

“…Consequently, the dominance of Achromobacter during the initial HuangQin cultivation period implies its pivotal role in root development, while the modest abundance of Burkholderiaceae may contribute to the accumulation of active ingredients in HuangQin. Pseudarthrobacter, exhibiting effects on growth enhancement and avonoid content augmentation in Geum aleppicum, evidenced its peak abundance in the second year, coinciding with the rapid growth phase of HuangQin and the accumulation of active ingredients (Fan et al 2023;Asimakoula et al 2023). However, with prolonged HuangQin cultivation, bene cial bacteria abundance declined gradually, as evidenced by the reduction in Pseudarthrobacter and unidenti ed_Burkholderiaceae from the second to fourth years.…”