Approximate analytical solutions for a biofilm reactor model with Monod kinetics and product inhibition

Bhaskar, G. V.; Bhamidimarri, S. M. Rao

doi:10.1002/cjce.5450690220

Cited by 15 publications

(3 citation statements)

References 8 publications

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“…That is, cells, like chemical reactors, are most efficient where catalytic activity is as high as it can be without significant limitations by diffusion. This concept of effectiveness factor has been well known and used by bioengineers for many systems including immobilized enzymes (Fink et al, 1973; Shimizu and Inoue, 1983; Wadiak and Carbonell, 1975), bacterial cells growing in biofilms (Bhaskar and Bhamidimarri, 1991; Buffiere et al, 1995; Vos et al, 1990; Zhang and Bishop, 1994), cells growing in bioreactors for tissue engineering and many other applications (Haugh and Schneider, 2006). With the increasing interest of bioengineers in tissues and organs, both in vivo and for cellular, metabolic, and tissue engineering, we are interested in testing Weisz's hypothesis for non‐diseased living tissue.…”

Section: Introductionmentioning

confidence: 99%

Reaction–diffusion constraints in living tissue: Effectiveness factors in skeletal muscle design

Dasika

Kinsey

Locke

2010

Biotech & Bioengineering

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A mathematical model was developed to analyze the effects of intracellular diffusion of O(2) and high-energy phosphate metabolites on aerobic energy metabolism in skeletal muscle. We tested the hypotheses that in a range of muscle fibers from different species (1) aerobic metabolism was not diffusion limited and (2) that fibers had a combination of rate and fiber size that placed them at the brink of substantial diffusion limitation. A simplified chemical reaction rate law for mitochondrial oxidative phosphorylation was developed utilizing a published detailed model of isolated mitochondrial function. This rate law was then used as a boundary condition in a reaction-diffusion model that was further simplified using the volume averaging method and solved to determine the rates of oxidative phosphorylation as functions of the volume fraction of mitochondria, the size of the muscle cell, and the amount of oxygen delivered by the capillaries. The effectiveness factor, which is the ratio of reaction rate in the system with finite rates of diffusion to those in the absence of any diffusion limitations, defined the regions where intracellular diffusion of metabolites and O(2) may limit aerobic metabolism in both very small, highly oxidative fibers as well as in larger fibers with lower aerobic capacity. Comparison of model analysis with experimental data revealed that none of the fibers was strongly limited by diffusion, as expected. However, while some fibers were near substantial diffusion limitation, most were well within the domain of reaction control of aerobic metabolic rate. This may constitute a safety factor in muscle that provides a level of protection from diffusion constraints under conditions such as hypoxia.

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Section: Introductionmentioning

confidence: 99%

Reaction–diffusion constraints in living tissue: Effectiveness factors in skeletal muscle design

Dasika

Kinsey

Locke

2010

Biotech & Bioengineering

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“…One of the options for reducing reactor size and costs (up to 25%) is to use fixed-film reactors having higher solids retention times (SRT) while simultaneously reducing hydraulic retention time (HRT) without compromising process efficiency (Lessel 1991;Rabinowitz 2 ). The fixed-film approach also provides higher volumetric productivity over suspended growth systems (Bhaskar and Bhamidimarri 1991). However, the most critical issue in designing fixed-film reactors is the selection of a suitable medium.…”

Section: Introductionmentioning

confidence: 99%

Assessment of short-HRT, on-line, fixed-film prefermentation of domestic wastewater for enhanced biological phosphorus removal

Mavinic¹,

Mahendraker²,

Rabinowitz³

et al. 2001

Can. J. Civ. Eng.

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In this work, pilot-scale, on-line, short-HRT fixed-film prefermenter systems were evaluated using Ringlace and Kaldnes fixed-film media for short chain volatile fatty acid (SCVFA) production, with screened raw domestic wastewater and primary effluent. In comparison to the control reactors without media, significant levels of SCVFA were generated in the fixed-film prefermenters. For the design considered in this study, the Ringlace media performed well, whereas the Kaldnes media resulted in clogging. The Ringlace media data show that, for a 60-min HRT, on-line prefermenter systems produced 11 and 5.5 mg/L of SCVFA (as acetic acid) with screened raw wastewater and primary effluent, respectively. Such a low HRT might translate into potential cost savings (up to 25%) in providing SCVFA to enhanced biological phosphorus removal (EBPR) plants and could lead to a completely new generation of prefermenter designs.Key words: domestic sewage, enhanced biological phosphorus removal systems, fixed film, prefermenter, short chain volatile fatty acids. Mavinic et al.Résumé : Dans ce travail, des systèmes en série à l'échelle pilote de préfermentation à film fixe et à temps de rétention hydraulique court ont été évalués, en utilisant des médias à film fixe Ringlace et Kaldnes pour la production d'acide volatile gras à chaîne courte, avec des eaux usées domestiques tamisées et de l'effluent primaire. En comparaison avec les réacteurs de contrôle sans média, des niveaux significatifs d'acides volatiles gras à chaîne courte ont été générés dans le préfermenteur à film fixe. Pour la conception considérée dans cette étude, le média Ringlace a bien performé, tandis que le média Kaldnes s'est encrassé. Les données du média Ringlace ont montré que, pour un temps de rétention hydraulique de 60 min, les systèmes de préfermentation en série ont produit 11 et 5,5 mg/L d'acide volatile gras à chaîne courte (sous forme d'acide acétique) avec les eaux usées domestiques tamisées et l'effluent primaire, respectivement. Un temps de rétention hydraulique si bas peut se traduire en des économies de coûts potentielles (jusqu'à 25%) en ajoutant des acides volatiles gras à chaîne courte aux systèmes d'enlèvement au phosphore biologique améliorés, et pourrait mener à une nouvelle génération de conceptions de préfermenteurs.Mots clés : eaux usées domestiques, systèmes d'enlèvement au phosphore biologique améliorés, film fixe, préfermenteur, acides volatiles gras à chaîne courte.[Traduit par la Rédaction] 626

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“…Ethanol, 2,3butanediol, formic acid, acetic acid, butyric acid, lactic acid, and free fatty acids (Borzani, 1995;Fond et al, 1985;Hamamci and Ryu, 1994;Kuhn et al, 1993;Misset et al, 1993;Richter and Becker, 1985;van den Heuvel et al, 1988) are a few examples of substances that result in product inhibition in E. coli as well as in general. Some effort has also been spent on modeling the inhibition kinetics (Bhaskar and Rao-Bhamidimarri, 1991;Lee and Rogers, 1983;Stefuca and Bales, 1990;Shukla and Chaplin, 1993), mainly via either linear or nonlinear kinetics. This distinction is important, as the resulting volumetric productivities are totally different.…”

Section: Introductionmentioning

confidence: 99%

Biotransformation of octane by E. coli HB101[pGEc47] on defined medium: Octanoate production and product inhibition

Rothen¹,

Sauer²,

Sonnleitner³

et al. 1998

Biotechnol. Bioeng.

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E. coli HB101[pGEc47], which is able to convert octane to octanoate, but cannot oxidize octanoate further, was grown on defined medium with glucose as carbon source in batch and continuous culture. The biomass yield on glucose decreased from 0.32 +/- 0.02 g g-1 in aqueous cultivations to 0.25 +/- 0.02 g g-1 in the presence of octane. Maximal octanoate productivities of 0.6 g L-1 h-1 were the same as found in cultivations on complex medium. The glucose-based carbon recovery in these experiments was 99 +/- 4% (in extreme, between 90% and 105%). An increase of the octane feed from 1% to 2% (v/v) or more led to washout of cells. This effect was reversible when the octane feed was decreased to its initial value of 1%. Analysis of experimental data by model simulation strongly suggested that washout was due to inhibition by octanoate only. Pulses of octanoate to a continuous culture grown on aqueous media were applied to analyze the inhibition further. Inhibition by acetate was not significant, but its presence in the medium reflected a physiological state that made the cells more sensitive to octanoate inhibition. Model simulation with linear inhibition kinetics could perfectly predict glucose consumption and the resulting glucose concentration. The linear type of inhibition was confirmed by a variety of batch experiments in the presence of different concentrations of octanoate. The glucose-based specific growth rate, mu, decreased linearly with increasing concentrations of octanoate and became zero at a threshold concentration pmax of 5.25 +/- 0.25 g L-1.

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Approximate analytical solutions for a biofilm reactor model with Monod kinetics and product inhibition

Cited by 15 publications

References 8 publications

Reaction–diffusion constraints in living tissue: Effectiveness factors in skeletal muscle design

Reaction–diffusion constraints in living tissue: Effectiveness factors in skeletal muscle design

Assessment of short-HRT, on-line, fixed-film prefermentation of domestic wastewater for enhanced biological phosphorus removal

Biotransformation of octane by E. coli HB101[pGEc47] on defined medium: Octanoate production and product inhibition

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