title: The role of autoinducer-2 in aerobic granulation using alternating feed loadings strategy.
abstract: Quorum sensing (QS) plays an important role in aerobic granulation while how QS system regulates the formation of aerobic granules needs further discussion. This study cultivated activated sludge in two identical sequencing batch reactors (R1 and R2) at different influent organic loading rate (OLR) strategies: R1 was operated using constant OLR (around 8.0kg/m(3)d), while R2 was operated at alternating OLR (4.0-17.0kg/m(3)d). Microbial aggregates appeared in R2 on day 19, while the morphology of sludge in R1 changed little compared with the initial sludge. The concentration of autoinducer-2 (AI-2) in R2 showed an ascending trend, along with the increase of cell adhesiveness. The total extracellular polymeric substances (EPS) amount and large molecular weight EPS of R2 rose steadily, which was different from R1. Some bacteria able to self-aggregate and promote EPS secretion were exclusive in R2. A mechanism about aerobic granulation at alternating OLR was proposed.
authors.affiliation: Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
authors.forename: Supu
authors.initials: S
authors.lastname: Sun
authors.affiliation: Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
authors.forename: Buyun
authors.initials: B
authors.lastname: Ma
authors.affiliation: Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
authors.forename: Chunli
authors.initials: C
authors.lastname: Wan
authors.affiliation: Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan.
authors.forename: Duu-Jong
authors.initials: DJ
authors.lastname: Lee
mesh_terms: D000332:Aerobiosis; D001419:Bacteria / Q000254:growth & development / Q000378:metabolism*; D001704:Biopolymers / Q000378:metabolism; D019149:Bioreactors; D006714:Homoserine / Q000031:analogs & derivatives* / Q000032:analysis / Q000096:biosynthesis; D007783:Lactones / Q000032:analysis; D053038:Quorum Sensing; D012722:Sewage; D018508:Water Purification / Q000379:methods*
chemical_list: D001704:Biopolymers; D007783:Lactones; C091088:N-octanoylhomoserine lactone; D012722:Sewage; D006714:Homoserine
keywords: Aerobic granulation; Alternating organic loading rate; Autoinducer-2; Cell adhesiveness; Extracellular polymeric substances (EPS)