Application of psychrotolerant quorum quenching Planococcus versutus sp. L10.15T to membrane bioreactors for biofouling control at low temperatures

Abstract

Bacterial quorum quenching (QQ) (e.g., degradation of N-acyl homoserine lactones (AHLs)) has been utilized to mitigate biofouling in membrane bioreactors (MBRs). However, the anti-biofouling efficiency of QQ bacteria may decrease at low temperatures. To enhance the resilience of QQ technology to cold climates, psychrotolerant Planococcus versutus sp. L10.15^T was applied to MBRs at 10 °C in the form of polymeric beads entrapping L10.15^T. The efficiency of AHL degradation by L10.15^T-beads was compared to that by beads entrapping Rhodococcus sp. BH4, a QQ bacterium that has been widely used in MBRs at room temperature. The AHL degradation by the L10.15^T-beads was more efficient than that by the BH4-beads for most types of AHLs tested at 10 °C. The application of the L10.15^T-beads to a continuous MBR at 10 °C exhibited that the anti-biofouling efficiency of L10.15^T was greater than that of BH4 through more effective reduction in extracellular polymeric substances in the biocake on the membrane surface.