Acceleration of biofilm formation in start-up of sequencing batch biofilm reactor using carriers immobilized with Pseudomonas stutzeri strain XL-2

P. stutzeri strain XL-2 initially immobilized on polypropylene carriers accelerated the biofilm formation in startup
of sequencing batch biofilm reactor (SBBR) (denoted R1). The biofilm formation in R1 was approximately
completed in 36 days, which was shorter than that of 48 days in an identical SBBR (denoted R2) without strain
XL-2. Meanwhile, R1 presented a rapid stabilization of NH4
+-N and TN removal to 81.7% and 72.4% respectively.
Surface plasmon resonance demonstrated that strain XL-2 enhanced the initial adhesion of carrier surface
due to the production of extracellular polymeric substances (EPS), which made it easier for other EPS-producing
strains, such as Thauera and Flavobacterium, to adhere to the carriers. PICRUSt revealed that biofilm in R1
presented relatively higher activity of EPS biosynthesis enzymes (glycosyltransferase and asparagine synthase).
Thus, high EPS content was obtained due to the application of carriers immobilized with strain XL-2 and finally
promoted the biofilm formation.