Impact of quorum quenching enzyme on the sulfide-driven autotrophic denitrification process

Quorum sensing and quorum quenching characteristics are common in nitrogen removal-related microorganisms and play important regulatory role in them. In this study, the sulfide-driven autotrophic denitrification (SDAD) process which could simultaneously removal nitrogen and sulfur was established, and the impact of quorum quenching enzyme on the process was investigated. SDAD process was successfully established in a sequencing batch reactor and finally reached 95 % of TN removal by adjusting the supplied nitrate and sulfide concentrations and reaction time. The addition of quenching enzyme (0.1–10.0 mg/L) generally increased the nitrate removal and decreased the extracellular polymeric substance secretion while that in 5 mg/L obviously increased the NOX− removal efficiency to 90.9 % from 85.6 %. Furthermore, the long-term addition of quenching enzyme enriched the functional genus Thiobacillus, increasing its abundance from 3.0 % to 52.0 %. Quorum quenching technology could be adopted for regulating SDAD process in actual wastewater treatment. [Display omitted] •SDAD process was established by adjusting the influent quality and reaction times.•The quenching enzyme (acyltransferase) effectively improved the nitrate removal.•The quenching enzyme (acyltransferase) increased the abundance of Thiobacillus.•The quenching enzyme (acyltransferase) addition decreased the secretion of EPS.•The quenching enzyme (acyltransferase) was beneficial for the stability of SDAD.