Influence of reduced water availability on Pseudomonas putida unsaturated biofilms and the role of alginate in desiccation tolerance

Chang, Woo-Suk

doi:10.31274/rtd-180817-32

Cited by 2 publications

(2 citation statements)

References 14 publications

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“…The EPS, specifically the total protein and the polysaccharide content, was determined by an extraction method (Chang, 2005). Briefly, E. coli cells were incubated on a 0.45-μm filter membrane on multiple mTEC agars overnight at 37°C to obtain the total amount of E. coli cell within the range of 3 × 10 10 to 6 × 10 10 cells, and then the membrane was placed in 30 mL of 0.85% (w/v) NaCl solution.…”

Section: Methodsmentioning

confidence: 99%

E. coli Surface Properties Differ between Stream Water and Sediment Environments

et al. 2016

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The importance of E. coli as an indicator organism in fresh water has led to numerous studies focusing on cell properties and transport behavior. However, previous studies have been unable to assess if differences in E. coli cell surface properties and genomic variation are associated with different environmental habitats. In this study, we investigated the variation in characteristics of E. coli obtained from stream water and stream bottom sediments. Cell properties were measured for 77 genomically different E. coli strains (44 strains isolated from sediments and 33 strains isolated from water) under common stream conditions in the Upper Midwestern United States: pH 8.0, ionic strength 10 mM and 22°C. Measured cell properties include hydrophobicity, zeta potential, net charge, total acidity, and extracellular polymeric substance (EPS) composition. Our results indicate that stream sediment E. coli had significantly greater hydrophobicity, greater EPS protein content and EPS sugar content, less negative net charge, and higher point of zero charge than stream water E. coli. A significant positive correlation was observed between hydrophobicity and EPS protein for stream sediment E. coli but not for stream water E. coli. Additionally, E. coli surviving in the same habitat tended to have significantly larger (GTG)5 genome similarity. After accounting for the intrinsic impact from the genome, environmental habitat was determined to be a factor influencing some cell surface properties, such as hydrophobicity. The diversity of cell properties and its resulting impact on particle interactions should be considered for environmental fate and transport modeling of aquatic indicator organisms such as E. coli.

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Section: Methodsmentioning

confidence: 99%

E. coli Surface Properties Differ between Stream Water and Sediment Environments

et al. 2016

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“…The main organic fouling feed solution contained alginic acid sodium salt (AA) derived from brown algae (Sigma Aldrich, UK). AA was chosen as a model foulant for polysaccharides found in wastewater [34], as well as polysaccharides excreted by Pseudomonas bacteria during biofilm formation [35]. Furthermore, AA was also chosen due to its suitability for use with confocal imaging microscopy.…”

Section: Organic Fouling Feed Solutionsmentioning

confidence: 99%

Influence of organic fouling layer characteristics and osmotic backwashing conditions on cleaning efficiency of RO membranes

Daly

Allen

Koutsos

et al. 2020

Journal of Membrane Science

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Fouling remains a prevalent and serious problem in industries using membrane processes.Efforts to mitigate fouling are improving, however, membrane fouling cannot be completely eliminated. Therefore fouling control via development of sustainable cleaning methods are crucial. Despite osmotic backwashing showing promise, little is understood about this cleaning method for removal of fouling from reverse osmosis (RO) membranes. This paper systematically examines how organic fouling characteristics and osmotic backwashing parameters influence cleaning efficiency. Alginic acid was used as a model foulant and numerous microscopy techniques, including confocal microscopy, scanning electron microscopy and atomic force microscopy were used to examine the membrane fouling before and after cleaning to gain a clearer understanding of the mechanisms involved. Increasing CaCl2 concentration in the fouling solution resulted in an increase in fouling layer thickness from 37 to 179 µm, due to the complexation of Ca 2+ and the carboxyl groups in the alginate.Osmotic backwashing efficiency with 0.7 M NaCl decreased as the fouling layer became thicker and the pure water flux (PWF) recovery decreased from 92% to 81%. Osmotic backwashing efficiency also decreased with increasing initial permeate flux, as less fouling was removed: the fouling generated at higher initial fluxes is largely irreversible, resulting in a denser and more compact fouling layer. In an effort to increase osmotic backwashing flux, a CaCl2 draw solution was used, however, the Ca 2+ ions were found to interact with the alginate in the fouling layer, rendering this method inefficient, when compared to NaCl draw solutions which originated similar osmotic backwashing fluxes. Interestingly, the fouling layer was found to swell from 16 µm to 141 µm, when osmotic backwashing was carried out with a NaCl draw solution, followed by contact with a low ionic strength solution used for PWF testing. This phenomenon does not occur to the same extent after backwashing with CaCl2. The same trends were obtained for bovine serum albumin (BSA) fouling, whilst humic acid (HA) did not display any swelling phenomena. However, it showed the same cleaning inefficiency when using CaCl2 as a draw solution.

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Influence of reduced water availability on Pseudomonas putida unsaturated biofilms and the role of alginate in desiccation tolerance

Cited by 2 publications

References 14 publications

E. coli Surface Properties Differ between Stream Water and Sediment Environments

E. coli Surface Properties Differ between Stream Water and Sediment Environments

Influence of organic fouling layer characteristics and osmotic backwashing conditions on cleaning efficiency of RO membranes

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