Near wall void growth leads to disintegration of colloidal bacterial streamer

Biswas, Ishita; Ghosh, Ranajay; Sadrzadeh, Mohtada; Kumar, Aloke

doi:10.1016/j.jcis.2018.03.074

Cited by 9 publications

(7 citation statements)

References 23 publications

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“…It is now known that streamers can break due to different kinds of instabilities. Biswas et al 2,33 have reported on two different kinds of instabilities leading to streamer failure events, which occur due to the creep response of the bacterial soft matter. After the initial increase, the flow rate decreases substantially, which should result in a corresponding decrease in streamer breakage events (as shear forces decrease).…”

Section: Resultsmentioning

confidence: 99%

“…filtration device. Recently, it has been suggested that bacterial streamers belong to a more generic category of "colloidal streamer" 33 formation as morphologically similar fouling modes have been observed in particle laden polymeric flows. 11 It has also been observed that the dynamics of these colloidal streamers is extremely complex and non-linear.…”

Section: Discussionmentioning

confidence: 99%

“…11 It has also been observed that the dynamics of these colloidal streamers is extremely complex and non-linear. 2,5,33 Figure 7 suggests that that biofouling due to streamer formation is likely a separate category of porous membranes fouling that calls for further investigation.…”

Section: Discussionmentioning

confidence: 99%

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Impact of bacterial streamers on biofouling of microfluidic filtration systems

2018

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We investigate the effect of biofouling in a microfluidic filtration system. The microfluidic platform consists of cylindrical microposts with a pore-spacing of 2 m, which act as the filtration section of the device. One of our key findings is that there exists a critical pressure difference above which pronounced streamer formation is observed, which eventually leads to rapid clogging of the device with an accompanying exponential decrease in permeate flow. Moreover, when streamers do form, de-clogging of pores also occurs intermittently, which leads to small time scale fluctuations [O(10 s)] superimposed upon the large time scale [O(10 min)] clogging of the system. These de-clogging phenomena lead to a sharp increase in water permeation through the microfluidic filtration device but rates the water quality as biomass debris is transported in the permeate. Streamer-based clogging shares similarities with various fouling mechanisms typically associated with membranes. Finally, we also show that the pH of the feed strongly affects biofouling of the microfluidic filtration system.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Impact of bacterial streamers on biofouling of microfluidic filtration systems

2018

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“…Moreover, fluorescent staining of the EPS allows the visualization of the streamers without altering their structural properties, as embedding tracers would do in thin filaments. 14,38,[46][47][48] In this study, we exploited eDNA staining in order to visualize the streamers and to obtain a detailed characterization of their morphology. This visualization approach is crucial for the reliability of the hydrodynamic and rheological characterization of the system, since the flow field and the force exerted on the streamers depend to a great extent on the details of their morphology.…”

Section: Discussionmentioning

confidence: 99%

A microfluidic platform for characterizing the structure and rheology of biofilm streamers

Savorana

Słomka

Stocker

et al. 2022

Preprint

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Biofilm formation is the most successful survival strategy for bacterial communities. In the biofilm lifestyle, bacteria embed themselves in a self-secreted matrix of extracellular polymeric substances (EPS), which acts as a shield against mechanical and chemical insults. When ambient flow is present, this viscoelastic scaffold can take a streamlined shape, forming biofilm filaments suspended in flow, called streamers. Streamers significantly disrupt the fluid flow by causing rapid clogging and affect transport in aquatic environments. Despite their relevance, the structural and rheological characterization of biofilm streamers is still at an early stage. In this work, we present a microfluidic platform that allows the reproducible growth of biofilm streamers in controlled physico-chemical conditions and the characterization of their biochemical composition, morphology, and rheology in situ. We employed isolated micropillars as nucleation sites for the growth of single biofilm streamers under the continuous flow of a diluted bacterial suspension. By combining fluorescent staining of the EPS components and epifluorescence microscopy, we were able to characterize the biochemical composition and morphology of the streamers. Additionally, we optimized a protocol to perform hydrodynamic stress tests in situ, by inducing controlled variations of the fluid shear stress exerted on the streamers by the flow. Thus, the reproducibility of the formation process and the testing protocol make it possible to perform several consistent experimental replicates that provide statistically significant information. By allowing the systematic investigation of the role of biochemical composition on the structure and rheology of streamers, this platform will advance our understanding of biofilm formation.

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“…These findings have implications for design and fabrication of biomedical devices and membranetype systems, as well as understanding bacterial growth and proliferation in natural porous media such as soil and rocks. Biswas et al (2018) visualized the development of biofilm streamers with 200 nm fluorescent polystyrene beads in a microfluidic device. Biofilm streamers exhibited instantaneous movement and long-term movement along the direction of the flow.…”

Section: Microfluidics In Biofilm Studiesmentioning

confidence: 99%