Effects of Mn2+ and humic acid on microbial community structures, functional genes for nitrogen and phosphorus removal, and heavy metal resistance genes in wastewater treatment. (1st July 2022)

• Record Type: Journal Article
• Authors: Li, Yonghui; Dong, Rong; Guo, Jiaxin; Wang, Lan; Zhao, Jianguo
• Is Part Of: Journal of environmental management. Volume 313(2022)
• Publication Date: 2022-07-01
• Subjects: Humic acid -- Mn2+ -- Microbial community structures -- Functional genes -- HMRGs; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2022.115028
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Considering the wide occurrence of Mn 2+ and humic acid (HA) in environmental media, the effects of Mn 2+ (5–16 mg/L) and HA (10 mg/L) on microbial community structures, functional genes for nitrogen and phosphorus removal, and heavy metal resistance genes (HMRGs) were investigated in wastewater treatment using sequencing batch bioreactors (SBRs). The treatment efficiencies of influent chemical oxygen demands (COD), NH4 + -N, and PO4 3- -P were unaffected during the entire operational processes irrespective of whether Mn 2+ and HA were supplied. Although the functional prediction of genetic information via sequencing analysis showed that the microbial activity was not influenced by Mn 2+ and HA from different SBRs, the abundance of dominant phyla ( Proteobacteria, Actinobacteriota, Firmicutes, and Bacteroidota ), classes ( Saccharimonadia, Gammaproteobacteria, and Bacilli ), and genera ( unidentified_Chloroplast, TM7a, Micropruina, Candidatus_Competibacter, Lactobacillus, OLB12, and Pediococcus ) was different. Compared to the SBR without Mn 2+ and HA supplementation, the abundance of functional genes for nitrogen and phosphorus removal ( nar G, nir S, nos Z, ppk, and pho D) and HMRGs ( cor A and mnt A) significantly increased under Mn 2+ stress, but significantly decreased with the addition of HA except for genes nir S and ppk . The abundance of genes cor A and mnt A was related to the partially dominant microbes and functional genes, and might be reduced by supplying HA. This study provides insight into the effects of Mn 2+ and HA on functional genes for nitrogen and phosphorus removal and HMRGs in wastewater treatment. Highlights: Pollutants removal was unaffected by Mn 2+ (5–16 mg/L) and HA (10 mg/L) supply. Microbial community structures were affected after long-term exposure to Mn 2+ and HA. HMRGs abundance was related to the partially dominant microbes and functional genes. HA might reduce HMRGs abundance in treatment of wastewater containing heavy metals.