Optimum quorum quenching bacteria concentration in the better-quality cell entrapping beads to control biofouling in membrane bioreactor

Abstract

Quorum quenching (QQ) by cell entrapping beads (CEBs) is known to inhibit biofouling by its biological and physical cleaning effect. Although there are better QQ media reported, due to the ease of fabrication of QQ-CEBs, this study focused on improving the quality of CEBs by comparing two distinct bead-making methods – polyvinyl alcohol-alginate (PVA-alginate) and phase inversion – and on finding the optimum concentration of QQ bacteria in the CEBs. The evaluation of PVA-alginate bead showed better uniformity, and higher mechanical and chemical strength in comparison with the phase inversion bead. Through the operations of two control membrane bioreactors (MBRs) (no bead, vacant bead) and four QQ-MBRs with different Rhodococcus sp. BH4 concentrations (2.5–15 mg cell ml⁻¹) in PVA-alginate CEBs, the maximum QQ effect was observed by 5 mg ml⁻¹ BH4 concentration beads. This implies that an optimum cell concentration of QQ-CEBs is crucial to economically improve MBR performance using QQ.

Keywords:

• Biofouling
• quorum quenching (QQ)
• cell entrapping beads (CEBs)
• Rhodococcus sp. BH4
• PVA-alginate method
• optimum cell concentration

Acknowledgement

This research was mainly funded by Serve Korea and also supported by the 2022 Research Fund of the University of Seoul (202204081018).

Rhodococcus BH4 strain was provided by Yonsei University, Korea.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research was mainly funded by Serve Korea and also supported by the 2022 Research Fund of the University of Seoul (202204081018).