Study on Screening and Denitrification Characteristics of Highly Efficient Aerobic Denitrifying Bacteria from Lake Sediments

Owing to rapid industrial and agricultural development, nitrate (NO₃⁻-N) in the aquatic environment has been increasing constantly, which poses a serious threat to human health. The NO₃⁻-N can be reduced by aerobic denitrifying bacteria to gaseous nitrogen under aerobic conditions. In this study, three mixed aerobic denitrifying bacteria (NH, XF, and WU) were screened from various lake sediments. The NO₃⁻-N removal efficiencies reached over 97% at 36 h incubation in the medium and 72.89%, 67.33%, and 80.22% at 55 h incubation in eutrophic lake water. Nitrogen balance results showed that aerobic denitrifying bacteria transformed 41.22%, 24.56%, and 47.99% of the total nitrogen into gaseous nitrogen, respectively. High-throughput sequencing results showed the dominant bacteria were Proteobacteria and Pseudomonas. The relative abundance of functional genes for denitrification was predicted utilizing PICRUSt2, which was consistent with the trend of the quantitative microbial element cycling results. This study will provide a novel approach for applying microbial remediation in aqueous environment.