Temperature and immigration effects on quorum sensing in the biofilms of anaerobic membrane bioreactors

Tabraiz, Shamas; Petropoulos, Evangelos; Shamurad, Burhan; Quintela-Baluja, Marcos; Mohapatra, Sanjeeb; Acharya, Kishor; Charlton, Alex; Davenport, Russell J.; Dolfing, Jan; Sallis, Paul J.

doi:10.1016/j.jenvman.2021.112947

Cited by 23 publications

(6 citation statements)

References 66 publications

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“…This suggested that lipid is a significant component of EPS in AnMBRs compared to AeMBRs, especially considering that the lipid content only made up 1% of EPS of mixed liquor in AeMBR . The regulation of protein expression by QS has been studied and proved for pure microbial anaerobes and mixed liquor in AnMBRs. − QQ was suspected to mainly retard the abundance of dominant AHL-regulated genus Anaerolineaceae by 19.32% and its bioactivities in mixed liquor in AnMBRs (Figure S1). Therefore, it was not surprising that QQ could mitigate the protein content of EPS by 24.02% (Figure a), which could lead to lower membrane fouling (Figure c).…”

Section: Resultsmentioning

confidence: 99%

Underestimation of Extracellular Lipid Contribution to Fouling in Anaerobic Membrane Bioreactors

Huang

et al. 2023

ACS Sustainable Chem. Eng.

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Extracellular lipids were mainly considered as microbial metabolites and precursors/inhibitors of methane production in anaerobic membrane bioreactors (AnMBRs). Nevertheless, the significance of lipid-related membrane fouling has rarely been explored and compared to that of common foulants such as carbohydrates and proteins in AnMBRs. This was the first work to fingerprint long-chain fatty acids (LCFAs) and investigate the underestimated lipid-related fouling in AnMBRs. The LCFAs of extracellular polymeric substances (EPSs), supernatant, and soluble microbial products (SMPs) of mixed liquor, cake layer, and permeate in AnMBRs were mainly composed of C16:0 and C18:0. The lipid content (9%) was comparable to the carbohydrate content in EPS (10%). Noticeably, lipids made up 16% in the supernatant, and it was comparable to the content of carbohydrates (14%), suggesting the importance of colloidal lipids in membrane fouling. Furthermore, SMP had a lipid content of 31%, higher than the carbohydrate content (10%). From a molecular weight cutoff point of view, similar high rejection of lipids (68.7%) compared to those of carbohydrate (64.97%, p > 0.05) and protein (58.56%, p > 0.05) suggested that complexes of lipids and other macromolecules were implicated in fouling formation. While quorum quenching can mitigate membrane fouling via reduction of proteins in EPSs and supernatants, it did not reduce lipid contents. Overall, the results suggested that lipids play a much more important role in membrane fouling formation in AnMBRs than that previously assumed.

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Section: Resultsmentioning

confidence: 99%

Underestimation of Extracellular Lipid Contribution to Fouling in Anaerobic Membrane Bioreactors

Huang

et al. 2023

ACS Sustainable Chem. Eng.

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“…In S4 where the change to 30-day SRT at the end of EP-2 was achieved by MLSS dilution, a sharp fall in CST MLSS after day 189 corresponding to a rapid increase in the separation rate at the start of the FIC test, matched by a reduction in time needed to reach the final volume. The reasons for these delayed but sudden shifts are unknown: they may be related to the passing of a threshold concentration for some component in the MLSS, or even to quorum behaviour of MLSS and biofilm organisms, a topic of growing interest for AnMBR performance and fouling [10,64]. Several researchers have investigated relationships between parameters such as CST or specific resistance to filtration (SRF) and MLSS dewaterability, membrane flux and fouling in both aerobic and anaerobic MBR [25,29,59,65].…”

Section: Frozen Image Centrifugationmentioning

confidence: 99%

Operation of Submerged Anaerobic Membrane Bioreactors at 20 °C: Effect of Solids Retention Time on Flux, Mixed Liquor Characteristics and Performance

2021

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Four flat-sheet submerged anaerobic membrane bioreactors ran for 242 days on a simulated domestic wastewater with low Chemical Oxygen Demand (COD) and high suspended solids. Organic loading was maintained around 1.0 g COD L−1 day−1, while solids retention time (SRT) was varied from 20–90 days. This was achieved at a constant membrane flux, maintained by adjusting transmembrane pressure (TMP) in the range 1.8-9.8 kPa. Membrane fouling was assessed based on the required TMP, with mixed liquors characterised using capillary suction time, frozen image centrifugation and quantification of extracellular polymeric substances (EPS). SRT had a significant effect on these parameters: fouling was least at an SRT of 30 days and highest at 60 days, with some reduction as this extended to 90 days. Operation at SRT <30 days showed no further benefits. Although operation at a short SRT was optimal for membrane performance it led to lower specific methane productivity, higher biomass yields and higher effluent COD. Short SRT may also have accelerated the loss of essential trace elements, leading to reduced performance under these conditions. A COD-based mass balance was conducted, including both biomass and methane dissolved in the effluent.

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“…4,5 QS, a microbial communication mechanism based on N-acyl homoserine lactones (AHLs) associated with biofouling, is known to play a significant role in regulating important microbial behaviors, including the formation of biofilm. 6,7 Thus, to address the issue of biofouling in AnMBR, it is necessary to gain comprehensive insight into microbial behavior and various environmental conditions that affect the formation and regulation of biofilm.…”

Section: Introductionmentioning

confidence: 99%

“…However, severe membrane biofouling decreases the flux and requires regular membrane cleaning and replacement leading to expensive operating costs, being the major bottleneck to the development and widespread application of AnMBR . Biofouling is primarily caused by complex biological interactions between the membrane surface and foulants, resulting in undesired microbial components adhering to the membrane surface and/or within membrane pores, with quorum sensing (QS) playing a crucial role. , QS, a microbial communication mechanism based on N -acyl homoserine lactones (AHLs) associated with biofouling, is known to play a significant role in regulating important microbial behaviors, including the formation of biofilm. , Thus, to address the issue of biofouling in AnMBR, it is necessary to gain comprehensive insight into microbial behavior and various environmental conditions that affect the formation and regulation of biofilm.…”

Section: Introductionmentioning

confidence: 99%

Biofouling Control by Facultative Quorum Quenching Bacteria in Anaerobic Membrane Bioreactors for High-Strength Wastewater Treatment

An,

Fan,

Wang

et al. 2023

ACS EST Eng.

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Quorum quenching (QQ) by bacterial strains has been demonstrated to be a cost-efficient approach for biofouling control in an anaerobic membrane bioreactor (AnMBR). In this study, a facultative anaerobic QQ consortium was screened and encapsulated in beads (QQ beads) to mitigate biofouling in AnMBR for high-strength wastewater treatment. The operation time of membrane fouling in QQ-AnMBR was 3.5 times longer than that of control-AnMBR. The biofouling mitigation was attributed to the QQ effect on the reduction of quorum sensing signals and extracellular polymeric substances (EPS) in the cake layer. However, the retarded membrane biofouling and lower EPS in the QQ-AnMBR led to a higher level of irreversible membrane resistance. The addition of QQ beads enriched the genus Thauera and Methanothrix, while reduced the abundance of Methanosarcina. Moreover, the relative abundance of QQ-related genes in the cake layer increased from 0.014% in the Control-AnMBR to 0.022% in the QQ-AnMBR. These findings indicate significant promise for the facultative anaerobic QQ strains in implementing a biofouling strategy in AnMBR for high-strength wastewater treatment.

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Temperature and immigration effects on quorum sensing in the biofilms of anaerobic membrane bioreactors

Cited by 23 publications

References 66 publications

Underestimation of Extracellular Lipid Contribution to Fouling in Anaerobic Membrane Bioreactors

Underestimation of Extracellular Lipid Contribution to Fouling in Anaerobic Membrane Bioreactors

Operation of Submerged Anaerobic Membrane Bioreactors at 20 °C: Effect of Solids Retention Time on Flux, Mixed Liquor Characteristics and Performance

Biofouling Control by Facultative Quorum Quenching Bacteria in Anaerobic Membrane Bioreactors for High-Strength Wastewater Treatment

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