Microbial regulation of interspecific interaction and metabolism in anammox process to achieve coadaptation to artificial sweeteners

Artificial sweeteners (ASs) were frequently detectable in wastewater, which pose high risks to human health and ecological security. The feasibility of anaerobic ammonium oxidation (anammox) process for treatment of ASs-containing wastewater was evaluated in this study. The 86-d continuous flow experiment results showed that 0-30 μg L^-1 cyclamate and acesulfame did not significantly affect the nitrogen removal efficiency (NRE) of anammox processes, which were 94.5 ± 3.0 % and 96.6 ± 2.5 %, respectively. Simultaneously, specific anammox activity (SAA) was inhibited by 15 μg L^-1 ASs. Fortunately, anammox consortia adapted to the ASs stress by secreting extracellular polymeric substance (EPS). The relative abundances of Candidatus Kuenenia slightly decreased by 0.2 % and 2.3 % under stress of two ASs, and the microbial diversity increased. In addition, the anammox consortia regulated metabolites expression by cell energy allocation. The dominant metabolic pathways were amino acid metabolism, lipid metabolism and nucleotide metabolism. Particularly, the abundances of 5-hydroxylysinonorleucine and L-hypoglycin A significantly increased with ASs concentrations, which were crucial for bacterial proliferation. The co-metabolism between different bacteria might contribute to the biodegradation of ASs. This work demonstrates the feasibility of anammox process to treat the ASs-containing wastewater and reveals the regulation and adaptation mechanism of anammox microbiota, which further drives the implementation and development of anammox process.