Activity of <i>Pseudomonas aeruginosa</i> in biofilms: Steady state

Bakke, Rune; Trulear, Michael Gerald; Robinson, J. A.; Characklis, William G.

doi:10.1002/bit.260261204

Cited by 142 publications

(76 citation statements)

References 8 publications

(1 reference statement)

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“…Rittmann (1982) found in the prior research that when other parameters were constant, the speed of biofilm detachment was proportional to 0.58 power of sheer stress. Bakke et al (1984) found that there was linear relationship between detach speed of biofilms and sheer stress. Horn et al (2003) deemed that the detachments of biofilms were the results of both fluid sheer stress and intensity of biofilm.…”

Section: Discussionmentioning

confidence: 97%

Surface topographic characteristics of suspended particulates in reclaimed wastewater and effects on clogging in labyrinth drip irrigation emitters

Liu

et al. 2011

Irrig Sci

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Drip irrigation is the most effective and reliable method for reclaimed wastewater irrigation. Emitter clogging is the major problem for extending the drip irrigation technology. The existence of suspended particulates in irrigation water is the main reason for the emitter clogging. However, the reclaimed wastewater quality is extremely complex, and there is a series of physical, chemical, and biological reactions between suspended particulates and other materials contained such as microorganisms, which make the characteristics of suspended particulates in reclaimed wastewater complicated. In this paper, two types of widely used wastewaters treated with fluidized-bed reactor (FBR) and biological aerated filter (BAF) processes respectively were selected. The scanning electron microscope (SEM) technology and fractal theory were used to quantitatively describe the characteristics of the surface topography of suspended particulates. The results showed that the suspended particulates in two reclaimed wastewater were flocculent and porous. The pore system mainly consisted of solid suspended particulates, and most areas between the particulates were filled with microbes and extracellular polymers (EPS). The complex structure of biofilms was formed. That the biofilms grew and detached in irrigation system and deposited continuously at the inlet and outlet of labyrinth path was the major reason for the emitter clogging. The surface topography of suspended particulates in both reclaimed wastewaters showed fractal and multifractal characteristics, and the fractal dimension could not characterize the local and microsingularity of particulates but multifractal dimension could. The uniformity of the distribution of sediment pores increased with the size. Comparatively, the uniformity of suspended particulates in reclaimed wastewater treated by FBR was lower. With operation of reclaimed wastewater irrigation system, the average discharge of emitters decreased continuously with obvious fluctuations. The clogging degree of emitters was low during the first 256 h, and the clogging degree of the two types of reclaimed water was similar. But then, the degree of clogging increased greatly, and the FBR treatment on the emitters discharge were more obvious than BAF. It was closely related to the growth, detachments and sediment of biofilms in the irrigation system. Hence, using the reclaimed wastewater treated by BAF for drip irrigation is more suitable.

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Section: Discussionmentioning

confidence: 97%

Surface topographic characteristics of suspended particulates in reclaimed wastewater and effects on clogging in labyrinth drip irrigation emitters

Liu

et al. 2011

Irrig Sci

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“…Authors studying wastewaters and industrial waters are divided between those who defend that the activity of sessile and planktonic bacteria is similar (Bakke et al, 1984;Characklis and Marshall, 1990) and those who reached opposite conclusions (Plas et al, 1994;Le Magrex et al, 1994). Quantitative data on bacterial growth kinetics in drinking water systems is scarce (Pedersen, 1990;Block et al, 1993;Boe-Hansen et al, 2002b), although such data would seem important for the proper design of distribution networks and reservoirs.…”

Section: Article In Pressmentioning

confidence: 99%

Dynamics of drinking water biofilm in flow/non-flow conditions

2007

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A B S T R A C TDrinking water biofilm formation on polyvinyl chloride (PVC), cross-linked polyethylene (PEX), high density polyethylene (HDPE) and polypropylene (PP) was followed in three different reactors operating under stagnant or continuous flow regimes. After one week, a quasi-steady state was achieved where biofilm total cell numbers per unit surface area were not affected by fluctuations in the concentration of suspended cells. Metabolically active cells in biofilms were around 17-35% of the total cells and 6-18% were able to form colony units in R 2 A medium. Microbiological analysis showed that the adhesion material and reactor design did not affect significantly the biofilm growth. However, operating under continuous flow (0.8-1.9 Pa) or stagnant water had a significant effect on biofilm formation: in stagnant waters, biofilm grew to a less extent. By applying mass balances and an asymptotic biofilm formation model to data from biofilms grown on PVC and HDPE surfaces under turbulent flow, specific growth rates of bacteria in the biofilm were found to be similar for both materials (around 0.15 day À1) and much lower than the specific growth rates of suspended bacteria (around 1.8 day À1 ).

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“…The density of planktonic bacteria may be driven quite low by the antibiotic but one expects that the wallattached cell density is largely unaffected. Thus we conclude that if (8) holds then introduction of antibiotic into the flow reactor will not be effective in eradicating the bacteria.…”

Section: The Factors G and T Have Natural Biological Interpretationsmentioning

confidence: 86%

“…Simple models do not attempt to provide much detail on the spatial structure of biofilms but aim to provide information on conditions suitable for biofilm establishment and maintenance and which model the formation of biofilms directly, starting from an inoculum of planktonic bacteria. Among the more widely known of these, we mention Topiwala and Hamer [55], Baltzis and Fredrickson [7], Bakke et al [8], and Pilyugin and Waltman [45]. Less known is the work of R. Freter and his group (Freter [25,24] and Freter et al [26,27]), who formulated a mathematical model to understand the phenomena of colonization resistance in the mammalian gut (stability of resident microflora to colonization).…”

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confidence: 99%

The Biofilm Model of Freter: A Review

Ballyk

Jones

Smith

2008

Lecture Notes in Mathematics

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Summary. R. developed a simple chemostat-based model of competition between two bacterial strains, one of which is capable of wall-growth, in order to illuminate the role of bacterial wall attachment on the phenomenon of colonization resistance in the mammalian gut. Together with various collaborators, we have re-formulated the model in the setting of a tubular flow reactor, extended the interpretation of the model as a biofilm model, and provided both mathematical analysis and numerical simulations of solution behavior. The present paper provides a review of the work in [5,6,4,52,50,36,33,32,35,34].Introduction. The ability of bacteria to colonize surfaces forming biofilms and thereby to create a refuge from the vagaries of fluid advection has stimulated a great deal of recent research in a variety of disciplines. The importance of wall growth was first made apparent to us from the work of microbiologist Rolf Freter and his colleagues [25,27,26,24]. Their mathematical models of the phenomenon of colonization resistance in the mammalian gut showed that bacterial wall attachment could play a crucial role in the observed stability of the natural microflora of the gut to invasion by non-indigenous microorganisms. The authors had the pleasure of learning of this work first hand from a lecture by Freter at the Microbial Ecology Workshop organized by Frank Hoppensteadt and Smith at Arizona State University in 1997. Our own work can be traced to a collaboration that began at this workshop.While Freter's model was formulated in a CSTR (chemostat) setting which is natural since this reactor mimics the mouse cecum, the animal model for gut research, we felt that another natural setting was the plug flow reactor (PFR) where bacterial motility, fluid advection, and other spatial effects could play a larger role. The flow reactor more accurately reflects the environment of the large intestine of humans. Thus, Ballyk and Smith formulated a family of models for microbial growth and competition for limiting substrate and wall-attachment sites in our first work [5]. This paper focused on describing the model equations which consist of a system of parabolic partial differential

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Activity of Pseudomonas aeruginosa in biofilms: Steady state

Cited by 142 publications

References 8 publications

Surface topographic characteristics of suspended particulates in reclaimed wastewater and effects on clogging in labyrinth drip irrigation emitters

Surface topographic characteristics of suspended particulates in reclaimed wastewater and effects on clogging in labyrinth drip irrigation emitters

Dynamics of drinking water biofilm in flow/non-flow conditions

The Biofilm Model of Freter: A Review

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