Browsing by Author "Bakke, Rune"

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Activity of Pseudomonas aeruginosa in Biofilms: Steady State
(1984-12) Bakke, Rune; Trulear, Michael Gerald; Robinson, J. A.; Characklis, William G.
Aerobic glucose metabolism by Pseudomonas aeruginosa in steady-state biofilms at various substrate loading rates and reactor dilution rates was investigated. Variables monitored were substrate (glucose), biofilm cellular density, biofilm extracellular polymeric substance (EPS) density, and suspended cellular and EPS concentrations. A mathematical model developed to describe the system was compared to experimental data. Intrinsic yield and rate coefficients included in the model were obtained from suspended continuous culture studies of glucose metabolism by P. aeruginosa. Experimental data compared well with the mathematical model, suggesting that P. aeruginosa does not behave differently in steady-state biofilm cultures, where diffusional resistance is negligible, than in suspended cultures. This implies that kinetic and stoichiometric coefficients for P. aeruginosa derived in suspended continuous culture can be used to describe steady-state biofilm processes.
Biofilm detachment
(Montana State University - Bozeman, College of Engineering, 1986) Bakke, Rune
Biofilm thickness measurements by light microscopy
(1986-07) Bakke, Rune; Olsson, P. Q.
Light microscopy has been used to measure biofilm thickness. The vertical displacement of the sample required to focus from the biofilm-liquid interface to the biofilm-substratum interface is measured by the stage micrometer. Biofilm thickness is proportional, but not equal, to the measured vertical displacement. An expression for the proportionality constant, kf, in terms of refractive indices is determined from a geometric analysis of the light path. kf can be estimated as the ratio of the refractive index of the film to the refractive index of the media interfacing the film between the objective lens and the sample. The thickness of any transparent film may be determined by light microscopy when the refractive index of the film is known.
Dynamics of biofilm processes : substrate load variations
(Montana State University - Bozeman, College of Engineering, 1983) Bakke, Rune
Fundamental Considerations of Fixed Film Systems
(1985) Characklis, William G.; Bakke, Rune; Trulear, Michael Gerald
Microbial Fouling and Its Control: A Phenomenological Approach
(1985-11) Characklis, William G.; Bakke, Rune; Yeh, An-I
Modeling production of extracellular polymeric substances in a Pseudomonas aeruginosa chemostat culture
(2001) Kommedal, R.; Bakke, Rune; Dockery, Jack D.; Stoodley, Paul
Formation of extracellular polymeric substances (EPS) by mucoid Pseudomonas aeruginosa is investigated using literature data from chemostat cultures. The data are used to calibrate a product formation regime allowing substrate sufficient and endogenous EPS formation. Yield coefficients for both formation conditions are elucidated based on metabolic pathway analysis, Growth and non-growth related specific formation rates of respectively 0.18 g CEPS/g Ccell/h and 0.03 1/h were estimated. The exogenous and endogenous EPS yield was found to be 0.77 g CEPS/g Cglu and 0.79 g CEPS/g Ccell, respectively. Being structurally equivalent to comprehensive maintenance models, this model allows for non-growth related product formation, showing the same quality of fit as previous models restricted to exogenous EPS precursors.
Nitrification and Autotrophic Denitrification in Calcium Alginate Beads
(1987-01) Lewandowski, Zbigniew; Bakke, Rune; Characklis, William G.
Immobilization of nitrifiers and autotrophic denitrifiers (Thiobacillus denitrificans) within calcium alginate gel was demonstrated. Calcium carbonate reagent was immobilized along with bacteria as the stabilizing agent. Protons released as a result of microbial respiration reacted with calcium carbonate producing calcium ions which internally stabilized the calcium alginate gel. The microbially active gel beads were mechanically stable and active for three months in a continuous flow system without addition of calcium.
Theoretical and Experimental Analysis of a Pseudomonas aeruginosa Biofilm
(1988) Characklis, William G.; Bakke, Rune; Turakhia, Mukesh Harilal
Theoretical and Experimental Analysis of a Pseudomonas aeruginosa Biofilm
(1988) Characklis, William G.; Bakke, Rune; Turakhia, Mukesh Harilal