Material modeling of biofilm mechanical properties

Laspidou, Chrysi; Spyrou, Leonidas A.; Aravas, N.; Rittmann, Bruce E.

doi:10.1016/j.mbs.2014.02.007

Cited by 28 publications

(24 citation statements)

References 20 publications

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“…The elasticity of polymers in the EPS may be accountable for compaction and relaxation behaviour of the biofilm [29][30][31]. Laspidou et al [13] showed that biofilm voids change in the deforming biofilm and that consolidation plays an important role in the mechanical properties, making old and consolidated biofilms overall stiffer. This study showed that compaction and subsequent relaxation of biofilms caused elevated biofilm stiffness (stiffer biofilm, Fig.…”

Section: Impact Of Biofilm Compaction and Relaxationmentioning

confidence: 99%

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Compaction and relaxation of biofilms

Linares

Wexler²,

Bucs

et al. 2016

Desalination and Water Treatment

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A B S T R A C TOperation of membrane systems for water treatment can be seriously hampered by biofouling. A better characterization of biofilms in membrane systems and their impact on membrane performance may help to develop effective biofouling control strategies. The objective of this study was to determine the occurrence, extent and timescale of biofilm compaction and relaxation (decompaction), caused by permeate flux variations. The impact of permeate flux changes on biofilm thickness, structure and stiffness was investigated in situ and non-destructively with optical coherence tomography using membrane fouling monitors operated at a constant crossflow velocity of 0.1 m s −1 with permeate production. The permeate flux was varied sequentially from 20 to 60 and back to 20 L m −2 h −1 . The study showed that the average biofilm thickness on the membrane decreased after elevating the permeate flux from 20 to 60 L m −2 h −1 while the biofilm thickness increased again after restoring the original flux of 20 L m −2 h −1 , indicating the occurrence of biofilm compaction and relaxation. Within a few seconds after the flux change, the biofilm thickness was changed and stabilized, biofilm compaction occurred faster than the relaxation after restoring the original permeate flux. The initial biofilm parameters were not fully reinstated: the biofilm thickness was reduced by 21%, biofilm stiffness had increased and the hydraulic biofilm resistance was elevated by 16%. Biofilm thickness was related to the hydraulic biofilm resistance. Membrane performance losses are related to the biofilm thickness, density and morphology, which are influenced by (variations in) hydraulic conditions. A (temporarily) permeate flux increase caused biofilm compaction, together with membrane performance losses. The impact of biofilms on membrane performance can be influenced (increased and reduced) by operational parameters. The article shows that a (temporary) pressure increase leads to more compact biofilms with a higher hydraulic resistance.

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Section: Impact Of Biofilm Compaction and Relaxationmentioning

confidence: 99%

“…In other words, the effect of permeate flux on hydraulic biofilm resistance was reversible. Recently, Laspidou et al [13] presented a biofilm model, in which compression of the biofilm resulted in the "closing" of voids making the biofilm material stiffer.…”

Section: Introductionmentioning

confidence: 99%

Compaction and relaxation of biofilms

Linares

Wexler²,

Bucs

et al. 2016

Desalination and Water Treatment

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“…The TMP determines the forces acting on the biofilms and in turn its internal biofilm organization, i.e., its packing. Applying a physical stress deforms the biofilm structure and changes the void space, thus reducing its porosity (Laspidou et al, 2014). The composition of biofilms likely governs its mechanical stability, i.e., to what extent the biofilm resists to the compression forces.…”

Section: Biofilms Are Compressible Structuresmentioning

confidence: 99%

The composition and compression of biofilms developed on ultrafiltration membranes determine hydraulic biofilm resistance

et al. 2016

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“…Biomass fragments can detach due to erosion by the flow. References [33,49] use this approach to predict local diffusion coefficients, permeability coefficients, and Young modulus variations taking into account the microstructure.…”

Section: Hybrid Modelmentioning

confidence: 99%

Differential growth of wrinkled biofilms

2015

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Biofilms are antibiotic-resistant bacterial aggregates that grow on moist surfaces and can trigger hospitalacquired infections. They provide a classical example in biology where the dynamics of cellular communities may be observed and studied. Gene expression regulates cell division and differentiation, which affect the biofilm architecture. Mechanical and chemical processes shape the resulting structure. We gain insight into the interplay between cellular and mechanical processes during biofilm development on air-agar interfaces by means of a hybrid model. Cellular behavior is governed by stochastic rules informed by a cascade of concentration fields for nutrients, waste, and autoinducers. Cellular differentiation and death alter the structure and the mechanical properties of the biofilm, which is deformed according to Föppl-Von Kármán equations informed by cellular processes and the interaction with the substratum. Stiffness gradients due to growth and swelling produce wrinkle branching. We are able to reproduce wrinkled structures often formed by biofilms on air-agar interfaces, as well as spatial distributions of differentiated cells commonly observed with B. subtilis.

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Material modeling of biofilm mechanical properties

Cited by 28 publications

References 20 publications

Compaction and relaxation of biofilms

Compaction and relaxation of biofilms

The composition and compression of biofilms developed on ultrafiltration membranes determine hydraulic biofilm resistance

Differential growth of wrinkled biofilms

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