Biofouling Control in an Anaerobic Membrane Bioreactor with Indigenous Quorum Quenching Bacterium Micrococcus luteus Strain AnQ-m1

This study isolated and screened indigenous strains quenching
the
acyl homoserine lactone (AHL)-mediated quorum sensing system and investigated
the effectiveness of a selected strain for biofouling control in a
laboratory-scale anaerobic membrane bioreactor (AnMBR). Among the
11 facultative anaerobes isolated from anaerobic sludge, Micrococcus luteus strain AnQ-m1 was screened out
as the most potent AHL degrader. Its AHL degradability was further
examined while encapsulating the cells in polysulfone–alginate
beads to optimize the encapsulation medium recipe. The QQ beads with
immobilized AnQ-m1 cells retarded the apparent membrane fouling rate
by 2.2 times compared with the AnMBR with vacant beads. C8-HSL, the
dominant AHL in AnMBRs, was effectively (∼70%) quenched in
the QQ-AnMBR before the membrane was fouled; however, its concentration
was increased to the normal level when the membrane was fouled. Polysaccharides
in a loosely bound extracellular polymeric substance were gradually
reduced at a constant rate during the QQ stage, while the indigenous
QQ strain barely affected the microbial community structure of the
bulk sludge and the water treatment performance of the AnMBR. These
findings provide new insights into the QQ-based biofouling control
strategy and highlight the beneficial effects of indigenous QQ strains
on AnMBR stability.