Salt stimulates sulfide-driven autotrophic denitrification: Microbial network and metagenomics analyses

Tong Wang; Han Wang; Xiaochuan Ran; Yayi Wang

doi:10.1016/j.watres.2024.121742

Salt stimulates sulfide-driven autotrophic denitrification: Microbial network and metagenomics analyses

Water Res. 2024 May 7:257:121742. doi: 10.1016/j.watres.2024.121742. Online ahead of print.

Authors

Tong Wang¹, Han Wang², Xiaochuan Ran¹, Yayi Wang³

Affiliations

¹ State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, PR China.
² State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, PR China. Electronic address: hanw@tongji.edu.cn.
³ State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, PR China. Electronic address: yayi.wang@tongji.edu.cn.

PMID: 38733967
DOI: 10.1016/j.watres.2024.121742

Abstract

Sulfur autotrophic denitrification (SADN) is a promising biological wastewater treatment technology for nitrogen removal, and its performance highly relies on the collective activities of the microbial community. However, the effect of salt (a prevailing characteristic of some nitrogen-containing industrial wastewaters) on the microbial community of SADN is still unclear. In this study, the response of the sulfide-SADN process to different salinities (i.e., 1.5 % salinity, 0.5 % salinity, and without salinity) as well as the involved microbial mechanisms were investigated by molecular ecological network and metagenomics analyses. Results showed that the satisfactory nitrogen removal efficiency (>97 %) was achieved in the sulfide-SADN process (S/N molar ratio of 0.88) with 1.5 % salinity. In salinity scenarios, the genus Thiobacillus significantly proliferated and was detected as the dominant sulfur-oxidizing bacteria in the sulfide-SADN system, occupying a relative abundance of 29.4 %. Network analysis further elucidated that 1.5 % salinity had enabled the microbial community to form a more densely clustered network, which intensified the interactions between microorganisms and effectively improved the nitrogen removal performance of the sulfide-SADN. Metagenomics sequencing revealed that the abundance of functional genes encoding for key enzymes involved in SADN, dissimilatory nitrate reduction to ammonium, and nitrification was up-regulated in the 1.5 % salinity scenario compared to that without salinity, stimulating the occurrence of multiple nitrogen transformation pathways. These multi-paths contributed to a robust SADN process (i.e., nitrogen removal efficiency >97 %, effluent nitrogen <2.5 mg N/L). This study deepens our understanding of the effect of salt on the SADN system at the community and functional level, and favors to advance the application of this sustainable bioprocess in saline wastewater treatment.

Keywords: Metagenomic analysis; Molecular ecological network; Saline wastewater; Sulfur autotrophic denitrification; Sulfur−oxidizing bacteria.