Forced modulation of biological processes: A review

Silveston, P. L.; Budman, Hector; Jervis, Eric

doi:10.1016/j.ces.2008.06.017

Cited by 28 publications

(6 citation statements)

References 44 publications

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“…Clearly, the value of the time scale must be large enough so that the mean uptake rate becomes constant and proportional to the mean specific growth rate. These time-averaged quantities are relevant to describe the pseudo-steady-state dynamics, however they are not applicable to the transient response (over time scales shorter than ) because they assume an instantaneous adaptation of the living system (Silveston et al, 2008). In view of improving the dynamical modelling of bioreactors, it is important to be able to prescribe a substrate uptake model valid on the shortest time scale possible.…”

Section: Introductionmentioning

confidence: 99%

A two-dimensional population balance model for cell growth including multiple uptake systems

Quedeville

Ouazaite

Polizzi

et al. 2018

Chemical Engineering Research and Design

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Section: Introductionmentioning

confidence: 99%

A two-dimensional population balance model for cell growth including multiple uptake systems

Quedeville

Ouazaite

Polizzi

et al. 2018

Chemical Engineering Research and Design

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“…Varying feed profiles were employed in the postinduction phase of recombinant streptokinase protein expression, including constant feed rates, linearly increasing feed rate and exponentially varying feed rates (Ramalingam et al, 2007) to evaluate the requirement of variable feed strategy. Modulation of an input such as a substrate or a nutrient concentration or the cell environment such as the pH can enhance the rates of biochemical reactions that are occurring (Silveston et al, 2008). A twofold increase in the concentration of plasmid bearing cells using square wave modulation of the dilution rate has been found.…”

Section: Early Population Dynamics Modelsmentioning

confidence: 99%

Population dynamics model for plasmid bearing and plasmid lacking cells for streptokinase production in continuous flow stirred tank bioreactor

Kumar¹,

Ghosh²

2010

Int. J. Eng. Sci. Tech

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Streptokinase production in bioreactor is well associated to cell population dynamics. It is an established fact that two types of cell populations are found to emerge from the initial pool of recombinant cell population. This phenomenon leads to an undesired loss in yield of the product. Primary metabolites, like acetic acid etc are formed as by-product of metabolism, has its influential role in regulating the competitive and inhibitory dynamics. Metabolites are found to play a crucial role since their threshold amount is assumed to promote the formation of plasmid lacking cells. On the other hand probability of plasmid loss has shown to follow a variable trend in the model dynamics. In this study a process model with coupled differential equations is designed to reveal the interaction among various parameters.

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“…However, this law is unable to predict the actual uptake rate under transient conditions because it is an integral formulation of the closure issue: an implicit hypothesis of quasi-steady state for the biotic phase is attached to this law and limits the validity of the mathematical model to cases where the biological phase evolves through a succession of equilibrium stages. Much experimental evidence of the inapplicability of this equilibrium law under transient conditions has been presented over the past decades (Pickett et al, 1979;Silveston et al, 2008). Several authors proposed modified forms for the uptake rate, including static approaches such as a metabolic excess contribution (Xiu et al, 1998) or a dynamic approach involving a differential equation for the uptake rate (Lambert & Kussell, 2014;Sonnleitner & Käppeli, 1986;Sweere et al, 1988).…”

Section: Introductionmentioning

confidence: 99%

The closure issue related to liquid–cell mass transfer and substrate uptake dynamics in biological systems

Morchain

Quedeville

Fox

et al. 2021

Biotech & Bioengineering

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An original dynamic model for substrate uptake under transient conditions is established and used to simulate a variety of biological responses to external perturbations. The actual uptake and growth rates, treated as cell properties, are part of the model variables as well as the substrate concentration at the cell-liquid interface. Several regulatory loops inspired by the structure of the glycolytic chain are considered to establish a set of ordinary differential equations. The uptake rate evolves so as to reach an equilibrium between the cell demand and the environmental supply. This model does not contain any of the usual algebraic closure laws relating to the instantaneous uptake, growth rates, and the substrate concentration, nor does it enforce the continuity of mass fluxes at the liquid-cell interface. However, these relationships are found in the steady-state solution. Previously unexplained experimental observations are well reproduced by this model. Also, the model structure is suitable for further coupling with flux-based metabolic models and fluid-flow equations.

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Forced modulation of biological processes: A review

Cited by 28 publications

References 44 publications

A two-dimensional population balance model for cell growth including multiple uptake systems

A two-dimensional population balance model for cell growth including multiple uptake systems

Population dynamics model for plasmid bearing and plasmid lacking cells for streptokinase production in continuous flow stirred tank bioreactor

The closure issue related to liquid–cell mass transfer and substrate uptake dynamics in biological systems

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