Shear‐induced detachment of biofilms from hollow fiber silicone membranes

Huang, Zhujun; McLamore, Eric S.; Chuang, Huey-Ru; Wen, Zhang; Wereley, Steven T.; Leon, J. L.C.; Banks, M. Katherine

doi:10.1002/bit.24631

Cited by 24 publications

(31 citation statements)

References 63 publications

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“…The focus of the study was not on the effect of biofilm properties or cultivation time on detachment as is extensively reported recently [41][42][43]. Rather, the results established that reproducibility with respect to detachment was possible, provided appropriate methods were used to classify detached particles.…”

Section: Discussionmentioning

confidence: 75%

Detachment characteristics of a mixed culture biofilm using particle size analysis

Walter

Safari

Ivanković

et al. 2013

Chemical Engineering Journal

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Detachment is a critically important aspect of biofilm processes; it impacts not only on the characteristics of the biofilm itself but also has general implications for the dissemination of pathogenic bacteria and the operation of biofilm reactors. The mechanisms of biofilm detachment are of fundamental importance in the analysis of biofilm processes. However the complexity of biofilm detachment creates difficulties in performing and analyzing experiments. It is necessary to identify if, under steady conditions, biofilms experiments are reproducible with respect to detachment. In this study mixed culture biofilms were cultivated under low shear conditions over four days in glass flow cells in triplicate under non-recirculation conditions. Detached particles were regularly sampled, were stained, filtered and analyzed using a fluorescence microscope to establish size distributions of detached cells and cell clumps. This study has shown that, despite the existence of a complex particle size distribution, reproducibility is possible in four day old mixed culture biofilms. This has important implications for the study of active or passive detachment in biofilm systems. This study also distinguished between erosion and sloughing following step increases in shear stress.

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Section: Discussionmentioning

confidence: 75%

Detachment characteristics of a mixed culture biofilm using particle size analysis

Walter

Safari

Ivanković

et al. 2013

Chemical Engineering Journal

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“…These same simulations do show a significant reduction in fluid velocity deep within the polymeric bulk; however, since this will only affect the transport of nutrients, the concentration of which is anyway very low deep within the film, this omission will make negligible difference to biofilm growth. The second deficiency in this model is that biomass detachment due to shear stresses has not been incorporated, although this is known to partly control biofilm thickness [44,45]. There is no reason why this cannot be introduced for a future work, possibly following the particle-removal criterion of Alpkvist and Klapper [19].…”

Section: Discussionmentioning

confidence: 99%

Linear surface roughness growth and flow smoothening in a three-dimensional biofilm model

Head

2013

Phys. Rev. E

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The sessile microbial communities known as biofilms exhibit varying architectures as environmental factors are varied, which for immersed biofilms includes the shear rate of the surrounding flow. Here we modify an established agent-based biofilm model to include affine flow and employ it to analyze the growth of surface roughness of single-species, three-dimensional biofilms. We find linear growth laws for surface geometry in both horizontal and vertical directions and measure the thickness of the active surface layer, which is shown to anticorrelate with roughness. Flow is shown to monotonically reduce surface roughness without affecting the thickness of the active layer. We argue that the rapid roughening is due to nonlocal surface interactions mediated by the nutrient field, which are curtailed when advection competes with diffusion. We further argue the need for simplified models to elucidate the underlying mechanisms coupling flow to growth.

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“…18,20–25 For example, biofilms developed under high shear stress up to 10 Pa were shown to be cohesively stronger. 15,21 The reduction of biofilm thickness was observed under a continuous exposure to shear stress up to 0.9 Pa. 21,22 During disinfectant exposure, shear can accelerate biofilm–disinfectant reaction by enhancing the mass transfer of disinfectant into the biofilms, 26 presumably leading to significant biofilm property variation. However, the combined effect of disinfectant exposure and shear stress on properties of biofilm grown under low-nutrient conditions over a longer time appears to be unreported.…”

Section: Introductionmentioning

confidence: 99%

Response of Simulated Drinking Water Biofilm Mechanical and Structural Properties to Long-Term Disinfectant Exposure

Shen

Huang

Monroy

et al. 2016

Environ. Sci. Technol.

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Mechanical and structural properties of biofilms influence the accumulation and release of pathogens in drinking water distribution systems (DWDS). Thus, understanding how long-term residual disinfectants exposure affects biofilm mechanical and structural properties is a necessary aspect for pathogen risk assessment and control. In this study, elastic modulus and structure of groundwater biofilms was monitored by atomic force microscopy (AFM) and optical coherence tomography (OCT) during three months of exposure to monochloramine or free chlorine. After the first month of disinfectant exposure, the mean stiffness of monochloramine- or free-chlorine-treated biofilms was 4 to 9 times higher than those before treatment. Meanwhile, the biofilm thickness decreased from 120 ± 8 µm to 93 ± 6–107 ± 11 µm. The increased surface stiffness and decreased biofilm thickness within the first month of disinfectant exposure was presumably due to the consumption of biomass. However, by the second to third month during disinfectant exposure, the biofilm mean stiffness showed a 2- to 4-fold decrease, and the biofilm thickness increased to 110 ± 7–129 ± 8 µm suggesting that the biofilms adapted to disinfectant exposure. After three months of the disinfectant exposure process, the disinfected biofilms showed 2–5 times higher mean stiffness (as determined by AFM) and 6–13-fold higher ratios of protein over polysaccharide, as determined by differential staining and confocal laser scanning microscopy (CLSM), than the nondisinfected groundwater biofilms. However, the disinfected biofilms and nondisinfected biofilms showed statistically similar thicknesses (t test, p > 0.05), suggesting that long-term disinfection may not significantly remove net biomass. This study showed how biofilm mechanical and structural properties vary in response to a complex DWDS environment, which will contribute to further research on the risk assessment and control of biofilm-associated-pathogens in DWDS.

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Shear‐induced detachment of biofilms from hollow fiber silicone membranes

Cited by 24 publications

References 63 publications

Detachment characteristics of a mixed culture biofilm using particle size analysis

Detachment characteristics of a mixed culture biofilm using particle size analysis

Linear surface roughness growth and flow smoothening in a three-dimensional biofilm model

Response of Simulated Drinking Water Biofilm Mechanical and Structural Properties to Long-Term Disinfectant Exposure

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