Change of extracellular polymeric substances and microbial community in biofouling mitigation by continuous vanillin dose in membrane bioreactor

Vanillin - a bioactive substance to interfere various biological activities - is reportedly able to mitigate fouling in a membrane bioreactor (MBR). However, impact of continuous dose of vanillin on treatment performance and microbial activities in MBR are still unknown. In this study, effects of vanillin on production of extracellular polymeric substances (EPS) and microbial community was investigated in lab-scale MBR under continuous dose of vanillin. Vanillin dose remarkably reduced membrane fouling in accordance with less development of cake layer. It was probably because bulk sludge contained more hydrophilic components and became less adhesive by lower abundance of Xanthomonadaceae and Chitonophagaceae, which are known to produce viscous EPS and hydrophobic lipopolysaccharides. In addition, filtration resistance of cake layer was probably reduced by less contents of SMP and LB-EPS due to inhibition of Flavobacterium and Xanthomonadaceae, which are biofilm forming bacteria and EPS producers. These results suggest that interference to microbial activity by continuous dose of vanillin alters characteristics of sludge EPS, thus effectively mitigate biofouling in MBR.

Automated summary

This study investigated the effects of vanillin on extracellular polymeric substances (EPS) and microbial community in an MBR. The results showed that vanillin remarkably reduced membrane fouling by inhibiting the production of viscous EPS and hydrophobic lipopolysaccharides. This interference to microbial activity effectively mitigated biofouling in the MBR.