Deciphering the influence of salinity stress on the biological aniline degradation system: Pollutants degradation performance and microbial response.

In order to evaluate the impact of salinity gradients on the aniline biodegradation system, six reactors at salinity concentrations (0%–5%) were established. The results presented the salinity except for 5% imposed negligible effects on aniline degradation performance. Nitrification had prominent resistance to salinity (0%–1.5%) while were significantly restrained when salinity increased. The total nitrogen (TN) removal efficiency of Z4 (1.5%) was 20.5% higher than Z1 (0%) during the stable operation phase. Moreover, high throughput sequencing analysis showed that halophilic bacterium, such as Halomonas , Rhodococcus , remained greater survival advantages in high salinity system. The substantial enrichment of Flavobacterium , Dokdonella , Paracoccus observed in Z4 ensured its excellent nitrogen removal performance. The close cooperation among dominant functional bacteria was strengthened when salt content was below 1.5% while exceeding 1.5% led to the collapse of metabolic capacity through integrating the toxicity of aniline and high osmotic pressure. • Salinity stress have minor effect on aniline degradation performance except for Z6. • The nitrogen removal performance were collapsed when salinity exceeded 1.5%. • The wild proliferation of HN-AD bacteria promoted nitrogen removal capacity in Z4. • Low salinity (0%–1.5%) enhanced the close collaboration among dominant genus obviously. [ABSTRACT FROM AUTHOR]