Induced mazEF-mediated programmed cell death contributes to antibiofouling properties of quaternary ammonium compounds modified membranes

• Published in: Water research (Oxford) Vol. 227; p. 119319
• Main Authors: Zhang, Xingran, Ma, Jinxing, Guo, Yu, Luo, Yi, Li, Fang, Wang, Zhiwei
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2022
• Subjects: Biofouling; Contact-killing; mazEF-mediated programmed cell death; Membrane technology; Quaternary ammonium compounds; Quaternary ammonium compounds; Contact-killing; Biofouling; mazEF-mediated programmed cell death; Membrane technology
• ISSN: 0043-1354; 1879-2448; 1879-2448
• DOI: 10.1016/j.watres.2022.119319

•Role of mazEF in the biofilm growth was elucidated for QAC modified membrane (QM).•The mazEF-mediated PCD in bacteria was caused by an increase in ROS accumulation.•The affected cells regulated population through a quorum sensing autoinducer EDF.•Long-term tests showed mazEF was responsible for the antibiofouling effect of QM. Functionalized antibiofouling membranes have attracted increasing attention in water and wastewater treatment. Among them, contact-killing antibiofouling membranes deliver a long-lasting effect with no leaching or release, thus providing distinctive advantages. However, the antibiofouling mechanism especially in the vicinity of the membrane surface remains unclear. Herein, we demonstrate that mazEF-mediated programmed cell death (PCD) is critical for the antibiofouling behaviors of quaternary ammonium compounds modified membranes (QM). The viability of wild type Escherichia coli (WT E. coli) upon exposure to QM for 1 h was decreased dramatically (31.5 ± 1.4% of the control). In contrast, the bacterial activity of E. coli with the knockout of mazEF gene (KO E. coli) largely remained (85.8 ± 5.2%). Through addition of quorum sensing factor, i.e., extracellular death factor (EDF), the antibacterial activity was significantly enhanced in a dilute culture, indicating that the density-dependent bacterial communication played an important role in the mazEF-mediated PCD system in biofouling control. Long-term study further showed that QM exhibited a better antibiofouling performance to treat feedwater containing WT E. coli, especially when EDF was dosed. Results of this study suggested that the bacteria on the membrane surface subject to contact killing could modulate the population growth in the vicinity via quorum-sensing mazEF-mediated PCD, paving a way to develop efficient antibiofouling materials based on contact-killing scenarios. [Display omitted]