Isolating a novel quorum quenching strain based on carbon source adaptability for bioaugmentation under different...

Bioaugmentation is a promising technology, however, the effectiveness is strongly affected by the carbon sources in the environment. In this study, a novel and highly efficient quorum quenching (QQ) strain, Bacillus sp. YN06, with strong competitiveness for multiple carbon sources, was isolated based on QQ activity and carbon source utilization ability for sludge bulking control. YN06 can degrade most N-acyl homoserine lactones (AHLs) within 0.5 h and efficiently utilize three representative carbon sources (glucose, sodium acetate, and alanine) within 15 h. Ultra-high-performance liquid chromatography-mass spectrometry analysis results indicated that YN06 possesses both lactonase and acylase degradation pathways of AHLs. Whole-genome sequencing revealed KPHLOLIN_00687 and KPHLOLIN_01283 as potential lactonases and KPHLOLIN_01350 as a potential acylase. Molecular docking analysis indicated that all three enzymes exhibited strong affinities toward various AHLs, particularly long-chain and 3-oxo-AHLs, consistent with the experimental degradation performance. Monod equation combined with ¹³C labeling experiments, revealed that YN06 exhibits stronger competitive ability for multiple carbon sources than activated sludge. Additionally, glucose was found to significantly enhance the expression of QQ genes. The immobilized YN06, when added into reactors with different carbon sources, was able to survive stably while maintaining high QQ activity and effectively reduced extracellular polymeric substances in the sludge, thereby controlling sludge bulking. This study proposes a novel strategy of selecting QQ bacteria based on carbon source utilization, achieving effective bioaugmentation and providing a new perspective for research on QQ bacteria.