title: Quorum quenching bacteria can be used to inhibit the biofouling of reverse osmosis membranes.
abstract: Over the last few decades, significant efforts have concentrated on mitigating biofouling in reverse osmosis (RO) systems, with a focus on non-toxic and sustainable strategies. Here, we explored the potential of applying quorum quenching (QQ) bacteria to control biofouling in a laboratory-scale RO system. For these experiments, Pantoea stewartii was used as a model biofilm forming organism because it was previously shown to be a relevant wastewater isolate that also forms biofilms in a quorum sensing (QS) dependent fashion. A recombinant Escherichia coli strain, which can produce a QQ enzyme, was first tested in batch biofilm assays and significantly reduced biofilm formation by P. stewartii. Subsequently, RO membranes were fouled with P. stewartii and the QQ bacterium was introduced into the RO system using two different strategies, direct injection and immobilization within a cartridge microfilter. When the QQ bacterial cells were directly injected into the system, N-acylhomoserine lactone signals were degraded, resulting in the reduction of biofouling. Similarly, the QQ bacteria controlled biofouling when immobilized within a microfilter placed downstream of the RO module to remove QS signals circulating in the system. These results demonstrate the proof-of-principle that QQ can be applied to control biofouling of RO membranes and may be applicable for use in full-scale plants.
authors.affiliation: Singapore Membrane Technology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore; Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore.
authors.forename: Hyun-Suk
authors.initials: HS
authors.lastname: Oh
authors.affiliation: Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore; School of Materials Science & Engineering, Nanyang Technological University, Singapore.
authors.forename: Chuan Hao
authors.initials: CH
authors.lastname: Tan
authors.affiliation: Singapore Membrane Technology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore; Interdisciplinary Graduate School, Nanyang Technological University, Singapore.
authors.forename: Jiun Hui
authors.initials: JH
authors.lastname: Low
authors.affiliation: Singapore Membrane Technology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore.
authors.forename: Miles
authors.initials: M
authors.lastname: Rzechowicz
authors.affiliation: Singapore Membrane Technology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore.
authors.forename: Muhammad Faisal
authors.initials: MF
authors.lastname: Siddiqui
authors.affiliation: Singapore Membrane Technology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore; Fairleigh Dickinson University, 1000 River Road, Teaneck, NJ, USA.
authors.forename: Harvey
authors.initials: H
authors.lastname: Winters
authors.affiliation: Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore; The School of Biological Sciences, Nanyang Technological University, Singapore; Centre for Marine Bio-Innovation, University of New South Wales, Sydney, Australia.
authors.forename: Staffan
authors.initials: S
authors.lastname: Kjelleberg
authors.affiliation: Singapore Membrane Technology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, Singapore. Electronic address: agfane@ntu.edu.sg.
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Fane
authors.affiliation: Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore; The School of Biological Sciences, Nanyang Technological University, Singapore; Centre for Marine Bio-Innovation, University of New South Wales, Sydney, Australia. Electronic address: rscott@ntu.edu.sg.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Rice
mesh_terms: D001419:Bacteria; D018441:Biofilms; D057219:Biofouling; D008567:Membranes, Artificial; D009995:Osmosis; D053038:Quorum Sensing
chemical_list: D008567:Membranes, Artificial
keywords: Biofilms; Biofouling; N-acylhomoserine lactone; Quorum quenching bacteria; Quorum sensing; Reverse osmosis