title: Performance and role of N-acyl-homoserine lactone (AHL)-based quorum sensing (QS) in aerobic granules.
abstract: The present study investigated the relationship between N-acyl-homoserine lactone (AHL)-based quorum sensing (QS) and the physico-chemical properties of aerobic granules. Stable mature granules were observed in SBR2 and SBR3 with average diameters of 0.96, and 1.49 mm, respectively. The sludge densities of aerobic granules in SBR2 and SBR3 were 1.0246, and 1.0201 g/mL, respectively, which were higher than that of flocculent sludge in SBR1 (1.0065 g/mL). The results showed that the activity of AHL-based QS in SBR2 and SBR3 amounted to 2.4- and 2.1-fold induction, however, that in SBR1 with flocculent sludge was 1.6-fold induction. In addition, the results also showed that the activity of AHL-based QS in the 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 prolonged starvation. Furthermore, the results showed that the enhancement of AHL-based QS favored the extracellular polymeric substance production of microorganisms in activated sludge. Thus, it could be concluded that aerobic granules showed higher AHL-based QS than flocculent sludge, which resulted from the higher sludge density of aerobic granules than flocculent sludge. AHL-based QS was related to the metabolism energy in the feast condition; however, in prolonged starvation, microorganisms would emit more AHL-like molecules to protect themselves to resist starvation. Moreover, the enhancement of AHL-based QS favored the EPS component productivity of the microorganisms in activated sludge, which contributed to maintain the aerobic granular structure.
authors.affiliation: School of Environment, Beijing Normal University, Beijing 100875, China; School of Water Resource and Environment, Shijiazhuang University of Economics, Shijiazhuang 050031, China.
authors.forename: Yaochen
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Environment, Beijing Normal University, Beijing 100875, China.
authors.forename: Junping
authors.initials: J
authors.lastname: Lv
authors.affiliation: School of Environment, Beijing Normal University, Beijing 100875, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhong
authors.affiliation: School of Environment, Beijing Normal University, Beijing 100875, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Hao
authors.affiliation: School of Environment, Beijing Normal University, Beijing 100875, China.
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School of Environment, Beijing Normal University, Beijing 100875, China. Electronic address: zjrtshua@sohu.com.
authors.forename: Jianrong
authors.initials: J
authors.lastname: Zhu
mesh_terms: D054742:Acyl-Butyrolactones / Q000737:chemistry*; D000332:Aerobiosis; D001419:Bacteria / Q000302:isolation & purification*; D053038:Quorum Sensing / Q000502:physiology*; D012722:Sewage
chemical_list: D054742:Acyl-Butyrolactones; D012722:Sewage
keywords: Aerobic granules; Extracellular polymeric substances; N-acyl-homoserine lactone; Quorum sensing