Effects of N-Acyl homoserine lactones (AHLs) on aerobic sludge granulation during the treatment of phenolic wastewater

This study examines the role of N-Acyl homoserine lactones (AHLs) in aerobic granular sludge (AGS) for the treatment of phenolic wastewaters. AGS was successfully formed with phenol removal efficiency of 99.7%. AHLs content displayed an initial rise followed by a decline, both C4-HSL and 3-oxo-C10-HSL are critical AHLs to regulate the concentration and composition of EPS, showing the highest concentrations in large granules. The content of EPS constantly increased to 149.4 mg/gVSS, and PN was predominantly found in small and large granules. Luteococcus was dominant genus constituting up to 54.9% after the granulation process, and exhibited a strong association with C4-HSL. The synthesis and dynamics of AHLs were mainly governed by AHLs-producing bacterial strains of Rhodobacter and Pseudomonas, and AHLs-quenching strains of Flavobacterium and Comamonas. This regulation occurred within the purview of the AHLs synthetic genes (lasI and bjaI), sensing genes (sdiA, cciR and bjaR1), and degradation genes (pvdQ).

本研究考察了N-酰基高丝氨酸内酯（N-Acyl homoserine lactones, AHLs）在用于含酚废水处理的好氧颗粒污泥（aerobic granular sludge, AGS）中的作用。研究成功培养得到苯酚去除率达99.7%的好氧颗粒污泥。AHLs含量呈现先上升后下降的变化趋势，其中C4-HSL与3-oxo-C10-HSL均为调控胞外聚合物（Extracellular Polymeric Substances, EPS）浓度与组成的关键AHLs，且二者在大颗粒污泥中浓度最高。胞外聚合物含量持续升至149.4 mg/gVSS，蛋白质（Protein, PN）主要富集于小颗粒与大颗粒污泥中。颗粒化过程完成后，黄体球菌属（Luteococcus）成为优势菌属，占比最高可达54.9%，且与C4-HSL存在显著相关性。AHLs的合成与动态变化主要由产AHLs的红杆菌属（Rhodobacter）、假单胞菌属（Pseudomonas）菌株，以及淬灭AHLs的黄杆菌属（Flavobacterium）、丛毛单胞菌属（Comamonas）菌株主导调控。该调控过程通过AHLs合成基因lasI、bjaI，感应基因sdiA、cciR、bjaR1以及降解基因pvdQ实现。