The Impact of C8-Hsl on the Performance and Mechanism of the Hn-Ad Bacteria-Chlorella Symbiotic System in Mabr

Abstract

To enhance the stable operation of membrane aerated biofilm reactor (MABR), this study introduced a symbiotic system composed of heterotrophic nitrification–aerobic denitrification (HN-AD) bacteria and Chlorella into the MABR, and compared it with a control system inoculated with HN-AD bacteria and activated sludge. The effects of adding 0.8 μM exogenous C8-HSL on biofilm formation and the efficiency of nitrogen and phosphorus removal were investigated by comparing systems with and without the signaling molecule. Results showed that 0.8 μM C8-HSL enhanced the removal efficiencies of ammonia nitrogen, total nitrogen (TN), and total phosphorus by 25.17%, 36.22%, and 38.74%, respectively, and increased extracellular polymeric substances (EPS) production by 68.62%. High-throughput sequencing identified Desulfomicrobium and Aliidiomarina as the dominant microorganisms involved in nitrogen and phosphorus removal. The nirB gene played a key role in the denitrification process, and phoBR gene was essential for phosphorus removal. This study provides theoretical support for the application of quorum sensing in MABR systems.

Keywords: C8-HSL, HN-AD, HN-AD bacteria-Chlorella symbiotic system, MABR, Nitrogen and phosphorus removal