Novel insights into self-defense function of anammox sludge under magnesium ions (Mg2+) stress based on Mg2+ transport system

Pengcheng Wang; Bin Lu; Xiaoli Chai

doi:10.1016/j.biortech.2024.131615

Novel insights into self-defense function of anammox sludge under magnesium ions (Mg²⁺) stress based on Mg²⁺ transport system

Bioresour Technol. 2024 Oct 10:131615. doi: 10.1016/j.biortech.2024.131615. Online ahead of print.

Authors

Pengcheng Wang¹, Bin Lu¹, Xiaoli Chai²

Affiliations

¹ State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
² State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China. Electronic address: xlchai@tongji.edu.cn.

PMID: 39395603
DOI: 10.1016/j.biortech.2024.131615

Abstract

Magnesium ion (Mg²⁺) plays an important role in the accumulation and stability of anaerobic ammonium-oxidizing bacteria (AnAOB). In this study, the response of anammox sludge to Mg²⁺ was comprehensively investigated by performance evaluation and metagenomics analysis. Appropriate Mg²⁺ (0.8 mmol/L) could improve the nitrogen removal performance, AnAOB activity, and the synthesis potential of some hydrophobic substances, while high Mg²⁺ (>1.6 mmol/L) has a negative effect. Meanwhile, Mg²⁺ transmembrane transport theory was introduced to reveal the response principle of AnAOB to Mg²⁺ from a novel insight. AnAOB may have a self-defense function based on the PhoQ/PhoP-MgtAB system. Low extracellular Mg²⁺ will activate this function to enhance Mg²⁺ influx, thereby improving the intracellular metabolism of AnAOB. Excessive Mg²⁺, however, dormant this function and induces Mg²⁺ efflux, which may decrease the intracellular Mg²⁺ and thus affect AnAOB metabolism. These findings provide valuable references for the Mg²⁺ regulation of anammox-based process.

Keywords: Anammox-based process; Divalent metal cation; Hydrophilic-hydrophobic substance; Magnesium-involved metabolism; Metagenomic analysis; Nitrogen removal performance.