近来，已有研究发现群体感应在生物膜的形成和结构保持方面发挥着重要的作用。那么，好氧颗粒污泥作为一种没有添加附着载体的特殊生物膜，到目前为止，有关群体感应和颗粒污泥之间关系的报道还很少。本研究以好氧颗粒污泥为研究对象，在好氧污泥颗粒化过程和结构保持中研究信号分子AHLs介导的群体感应机制和特征，探明好氧颗粒污泥中信号分子AHLs介导的群体感应作用，同时，希望本研究结果不但可以丰富颗粒污泥形成的内在机理，而且通过调控赖于信号分子AHLs介导的群体感应活性，建立快速培养好氧颗粒污泥的方法并在实际废水处理中得到应用。主要研究结果如下：(1) 建立了用生物检测法定性、定量检测好氧颗粒污泥污泥混合培养体系中信号分子AHLs的方法。利用以Agrobacterium. tumefaciens NTL4为报告菌可有效定性和相对定量检测出混合培养体系活性污泥系统中的信号分子AHLs。研究发现相同运行条件下的SBRs反应器中，成熟颗粒污泥中信号分子AHLs的含量要高于絮体污泥，这是由于相比絮体污泥，颗粒污泥的污泥密度更高。并且不同粒径大小的颗粒污泥之间，信号分子AHLs介导的群体感应活性也有差异，通常，与大颗粒污泥相比，由于新生成小颗粒污泥具有更紧实的结构和更高的细胞密度，新生成小颗粒污泥中信号分子AHLs的含量要略高。（2）研究了SBR反应器基质降解过程中AHLs介导的群体感应动态变化特征。在基质降解和能量代谢过程中，存在富贫营养交替的变化环境。在富营养阶段，活性污泥中AHLs介导的群体感应活性和能量代谢有关。当营养基质可为活性污泥中的微生物提供足够的新陈代谢能量时，活性污泥表现出较高的AHLs介导的群体感应活性。当营养基质消耗殆尽时，由于营养基质的匮乏，微生物难以获得足够的能量时，活性污泥则表现出较差的群体感应活性。然而，当贫营养时间适当延长时，活性污泥中的微生物为了存活，将会分泌产生较多的信号分子AHLs以加强彼此间的协作交流共同抵抗饥饿的环境。（3）重点研究了颗粒化过程中信号分子AHLs介导的群体感应之间的关系以及信号分子在颗粒化过程中的作用，发现好氧污泥颗粒化过程和信号分子AHLs介导的群体感应活性存在正相关关系，并在颗粒化过程中起着非常重要的作用。颗粒化过程中信号分子AHLs定量检测结果显示，随着颗粒化的进程，信号分子AHLs介导的群体感应活性逐渐增强，表明信号分子AHLs介导的群体感应是好氧污泥颗粒化的必要条件。并且，仅仅当污泥密度超过1.010 g/mL时，信号分子AHLs介导的群体感应才能激活并调控污泥聚集形成颗粒的表型反应。信号分子AHLs阻断实验证明信号分子AHLs在污泥聚集过程中发挥着重要的作用。信号分子AHLs被淬灭酶acylase阻断后，经过6 h培养，颗粒污泥中的信号分子AHLs的含量下降了36.7%，附着聚集能力下降了29%。这样的结果说明信号分子AHLs在污泥聚集过程中发挥着重要的作用。其次，信号分子AHLs的阻断，直接影响了颗粒污泥中EPS、PN、PS的产量，EPS和PN分别下降了20%和15.6%，污泥的疏水性能从原来的70.6%下降到50.7%，疏水性能明显减弱。因此，活性污泥中信号分子AHLs介导的群体感应也能够通过调控EPS的产量来调控颗粒化过程。所以，信号分子AHLs对于好氧污泥颗粒化过程不仅是必要条件，在污泥聚集形成颗粒的过程中也起着非常重要的作用。（4）研究了信号分子AHLs在颗粒污泥结构稳定性中所发挥的作用，发现了信号分子在好氧颗粒污泥结构稳定性中发挥着重要的作用。通过信号分子AHLs阻断实验，发现了信号分子AHLs阻断降低了颗粒污泥的聚集强度，大量细小活性污泥从颗粒污泥中游离出来，颗粒污泥系统中上清液浊度明显上升，而且颗粒污泥也失去了光滑的外表和清晰的外观轮廓。信号分子AHLs阻断，致使颗粒污泥系统中信号分子AHLs的含量减少。与对照相比，添加了淬灭酶的颗粒污泥，经过5天的试验，颗粒污泥中AHLs的含量下降了约36.4%，到第10天颗粒污泥中信号分子AHLs的含量持续下降了40.8%。信号分子AHLs阻断导致颗粒污泥聚集性能变差。连续的动态试验表明，经过5天连续阻断测定，与对照相比，颗粒污泥附着聚集性能下降了43.6%。并且，颗粒污泥的附着聚集能力持续减弱，到第10天，与对照相比，附着聚集性能下降了55.6%。信号分子AHLs的阻断影响了颗粒污泥系统中EPS的产量和组成比例，这说明EPS的组成空间结构发生改变，EPS含量的减少和组分比例的变化可直接削弱微生物之间联系的骨架结构，致使颗粒污泥发生解体。另外EEM测定结果显示，添加了淬灭酶的颗粒污泥中疏水性物质明显减少，疏水性能明显减弱，也是颗粒污泥发生解体的另外一个因素。（5）基于AHLs介导的群体感应理论，研究了快速培养好氧颗粒污泥的方法和机理。以成熟的好氧颗粒污泥为信号分子AHLs的供体，采取向絮体污泥中添加颗粒污泥来强化絮体污泥向颗粒污泥的转化。当添加颗粒污泥较少时，不会起到强化的作用，反而会导致添加颗粒污泥的解体，但是污泥沉降性能有所改善。当添加颗粒污泥的量和系统中絮体污泥一样多时，絮体污泥向颗粒污泥的转化速度加快。因为成熟颗粒污泥含有更多的信号分子AHLs，所以颗粒污泥的添加，可增强絮体污泥系统的信号分子AHLs介导的群体感应活性，从而促进絮体污泥聚集能力的增强，最终实现颗粒化。外源性信号分子（C6-HSL、C8-oxo-HSL、C10-oxo-HSL、C12-oxo-HSL）促进絮体污泥附着聚集实验进一步证明了外源性的信号分子的添加可以促进絮体污泥附着和聚集生长。（6）初探在实际城市污水中快速培养好氧颗粒污泥的方法。即向絮体污泥系统中添加其它颗粒污泥，因为接种颗粒污泥也是具有较强的群体感应活性的生物聚集体。尽管在向好氧环境转变的过程中，污泥的活性和群体感应活性会有所下降，但是，随着驯化时间的延长，可成功实现好氧颗粒污泥的转化，并在实际废水处理中发挥一定的作用。

Recently, some studies have confirmed that quorum sensing (QS) is related with some bacterial biofilms, which not only participate in the development of biofilms, but also involve in the structure of biofilm. Aerobic granular sludge is developed through self-immobilization of microorganisms without addition of biocarriers, and is regarded as special “biofilm” growth. However, so far, there are little reports about relationship between QS and the special biofilm of “aerobic granules”. Therefore, in this study, the mechanism and characteristics of N-acyl homoserine lactones (AHLs)-based QS were studied during the process of aerobic granulation and remaining its stability，which main aims are to gauge the role and importance of AHLs-based QS in aerobic granules. Moreover, it is explored to reveal the secret of granulation from the perspective of QS at the level of AHLs, and offer new insight into the microbiological control technique for rapid aerobic granulation and the treatment of municipal wastewater with aerobic granules. The main conclusions of this study are listed below:1. Biological detection technology for AHLs with the biosensor of Agrobacterium. tumefaciens NTL4 was very effective to gauge the activities of AHLs-based QS in mixed culture of activated sludge. The plate assay was very sensitive to the qualitative detection of AHLs in mixture system of activated sludge. The measurement of relative AHL content carried out in this study could characterize the relative amounts of AHLs. Furthermore, the relationship between AHL-based QS and physico-chemical properties of aerobic granule was investigated in this study. Stable mature granules were observed in the SBR2 and SBR3 with average diameter about 0.96, 1.49 mm, respectively. The sludge density of aerobic granules in SBR2 and SBR3 was about 1.0246, 1.0201 g/mL, which were higher than that of flocculent sludge (1.0065 g/mL) in SBR1. The results showed that the activity of AHL-based QS in SBR2 and SBR3 was about 2.4, 2.1 fold induction, however, it was about 1.6 fold induction in SBR1 with flocculent sludge. Thus, it could be concluded that aerobic granules showed higher AHL-based QS than flocculent sludge, which resulted from higher sludge density of aerobic granules than flocculent sludge.2. The performance and characteristic of AHLs-based QS in aerobic granules and activated sludge flocs were investigated during SBR operation. The aeration period in SBR operation consists of two stages: a degradation stage in which substrate is consumed and aerobic starvation stage in which substrate is no longer available. The results showed that the activity of AHL-based QS in three reactors rose in the feast condition, and then dropped with the consumption of substrate. However, the activity of AHL-based QS in these three reactors recovered again in the prolonged starvation. Furthermore, the results also showed that the enhancement of AHL-based QS favored the EPS production of microorganism in activated sludge, which contributed to maintain aerobic granular structure. Above all, AHL-based QS was related to the metabolism energy in feast condition, however, in prolonged starvation, microorganism would emit more AHL-like molecules in order to protect itself from resisting the starvation. 3. The role of AHL-based QS in aerobic granulation was investigated in this study. Results showed that AHLs were necessary to the typical aerobic granulation, and AHL-associated coordination of bacteria in sludge aggregation was sludge density dependent, only when it reached a threshold of 1.010 g/mL, AHL-based QS was activated to regulate aerobic granulation. Furthermore, a quorum quenching method was adopted to investigate the role of AHLs in aerobic granules. Results showed inhibition of AHL by acylase reduced the AHLs content about 36.7% in aerobic granules, and further weakened its attachment potential about 29%, which proved AHLs play an important role in the formation of aerobic granules. Additionally, the assay of quorum quenching proved that AHL-based QS could regulate EPS production, the production of EPS and PN were reduced about 20% and 15.6% respectively, and hydrophobicity of sludge decreased from 70.6% to 50.7%. These results provided additional evidence for the role of AHLs in aerobic granulation by regulation EPS concentration and its component proportion.4. In this study, porcine kidney acylase, as AHLs-degradation enzyme, was employed for the first time to directly investigate the role of AHLs in the structure stability of aerobic granules. Results clearly showed that inactivation of AHLs by AHLs-acylase could weaken the stability of aerobic granule. A lot of small active sludge separated from the aerobic granules, which resulted in supernatant turbidity increased obviously and smooth appearance of aerobic granules lost. In the presence of AHLs-acylase, AHLs were degraded by hydrolyzing the amide linkage, which resulted in aerobic granular attachment potential and activity of AHLs-based quorum sensing significantly reduced about 55.6%, 40.8%, respectively. In addition, it was also found that inactivation of AHLs led to reduction of extracellular polysaccharides and protein (PN), especially PN, and induced extracellular polymeric substances matrix damaged, which was hostile to stability of aerobic granules. This study provided direct evidence that AHLs played a key role in improving aerobic granular stability, and a potential way to enhance long-term stability of aerobic granules.5. The strategy of intermittent adding granular sludge was applied to cultivate aerobic granules rapidly in this study. The addition of aerobic granules, as the donor of AHLs signal molecules, into floc sludge system could promote the transformation of sludge from floc to granules. When addition of granular sludge was less about 30% of the total sludge flocs, it could not promote the floc sludge to transform to the granules, instead of leading to the disintegration of granular sludge. When the amount of adding aerobic granules reached the 100% of the total sludge flocs, the aggregating performance of flocs sludge was promoted to form aerobic granules, which could result from the enhancement of AHLs-based QS due to the addition of aerobic granules. Therefore, it could be looked as an effective method to fast developing the aerobic granules through adding mature aerobic granules into sludge flocs. 6. A preliminary study was developed that aerobic granular sludge was cultivated for the treatment of municipal wastewater. Granules sludge in Yanjing brewery have higher AHLs-based QS than flocs sludge，which were added into flocs sludge system in order to be transformed into aerobic granules. During the transformation of aerobic environment, although, the activity of AHLs-base QS of these granular sludge was dropped in the beginning stage, finally, these granular sludge was converted into aerobic granular sludge successfully. And then these aerobic granles played a role in the practical wastewater treatment.