Periodic optimization of continuous microbial growth processes

Em, Abulesz; Lyberatos, G.

doi:10.1002/bit.260290904

Cited by 43 publications

(19 citation statements)

References 36 publications

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“…[6][7][8] The dimensionless factor TRANS, which is related to the average mRNA concentration at steady-state conditions, can be calculated by:…”

Section: Editor's Notementioning

confidence: 99%

Elevation of Protein Synthesis by the Phenomenon of Biological Resonance

SchmidAndreas

2014

Industrial Biotechnology

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On a system-theoretical basis, the phenomenon of ''biological resonance'' can be described with a genetically structured model. The cell's protein regulation system is stimulated by external attraction with alternating periods of substrate supply and starvation to increase the enzyme synthesis rate (integral mean value), which leads to a higher concentration level compared to the synthesis rate under steady-state conditions. Maximal synthesized enzyme concentration depends on substrate supply and subsequent starvation periods and occurs both at coordinative and sequential inductions. Sequential induction is characterized by a considerably larger increase in the enzyme synthesis rate compared to coordinative induction, presumably because of the longer time delays between induction procedures and repression mechanisms. The simulations performed in this study by varying flow rate and substrate/inductor concentrations illustrate these to be additional parameters able to influence and optimize the phenomenon of biological resonance. Coordinative induction shows relatively insensitive behavior compared to these process parameters. However, the sequential induction rate can be influenced by both parameters and provides a basis for additional optimization of the microbial protein induction rate.

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“…[6][7][8] The dimensionless factor TRANS, which is related to the average mRNA concentration at steady-state conditions, can be calculated by:…”

Section: Editor's Notementioning

confidence: 99%

Elevation of Protein Synthesis by the Phenomenon of Biological Resonance

SchmidAndreas

2014

Industrial Biotechnology

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“…The criterion was formulated by Bittanti et al 23 and extensively applied to chemical 30,31 and biochemical [14][15][16][17] processes. In what follows, we give a brief outline of the procedure and mainly discuss the implementation of the different waveforms considered in the previous Section.…”

Section: The P-criterionmentioning

confidence: 99%

“…), and their impact on the performances was studied both experimentally 1,[8][9][10][11][12] and theoretically (evolutionary algorithms, 13 second variation methods [14][15][16][17][18][19] and direct numerical simulations 20 ). In spite of the number of contributions devoted to those topics, the assessment of proper waveforms for the forcing was seldom addressed in the literature.…”

Section: Introductionmentioning

confidence: 99%

On the choice of the optimal periodic operation for a continuous fermentation process

D’Avino

Crescitelli

Maffettone

et al. 2010

Biotechnology Progress

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In this contribution we investigate the impact of the forcing waveform on the productivity of a continuous bioreactor governed by an unstructured, nonlinear kinetic model. The (periodic) forcing is applied on the substrate concentration in the feed. To this end, some alternative waveforms commonly encountered in practice are evaluated and their performance is compared. An analytical/numerical approach is used. The preliminary analytical step is based on the π-criterion that gives useful information for small amplitudes. The extension to larger amplitudes, when significant improvements are expected, is then performed through a continuation-optimization procedure. It is found that the choice of the specific waveform has an impact on the performance of the process and there is no unique best forcing for any process condition, but its choice depends on the operating parameters and the forcing amplitude and frequency values. Further, the influence of the waveform functions on the wash-out conditions are extensively examined. The analysis shows that all the waveforms examined in this work may lead to significant enlargement of the nontrivial regime with respect to a steady state operation. In particular, square-wave forcing leads in practice to the extinction of the wash-out conditions for any feed substrate concentration and for a well defined choice of the forcing parameters.

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“…Feed concentration forcing of many non linear chemical and bio-chemical processes gives a superior time-averaged performance to that obtained under conventional steady-state operation [1][2][3]. One important class of concentration forcing (periodic operation) of bio reactors is the one in which the steady-state condition is chosen arbitrarily and the average value of the periodic input is the same as in the conventional steady state condition.…”

Section: Introductionmentioning

confidence: 99%

“…The time-averaged performance (for example conversion) is then compared with that obtained under steady-state operation. A number of experimental and theoretical studies are available on the periodic operation of bio reactors [2,3]. In all these studies, the steady-state condition for a given particular operating variable is considered.…”

Section: Introductionmentioning

confidence: 99%

Periodic operation of well mixed enzyme reactors with steady state multiplicities using relay feedback

Suresh

Chidambaram

1997

Bioprocess Engineering

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Periodic operation of a well mixed enzyme reactor with input and output multiplicities is theoretically analyzed. The system is an isothermal continuously stirred tank enzyme reactor with a non ideal mixing represented by a Cholettes' model and a reaction kinetics given by k 1 c/(k 1 c;1)2. The system exhibits input multiplicities and output multiplicities. Some of the input steady-states correspond to unstable steady-states. The periodic operation in the inlet feed concentration cannot be done by open loop oscillation method. Relay feedback method is essential for the periodic operation of such systems. The improvement in the average conversion is calculated for the two unstable input steady-states. Higher average conversion is obtained at the largest value of the feed concentration. The limitation of relay feedback method for the stable input steady-state is also brought out.

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Periodic optimization of continuous microbial growth processes

Cited by 43 publications

References 36 publications

Elevation of Protein Synthesis by the Phenomenon of Biological Resonance

Elevation of Protein Synthesis by the Phenomenon of Biological Resonance

On the choice of the optimal periodic operation for a continuous fermentation process

Periodic operation of well mixed enzyme reactors with steady state multiplicities using relay feedback

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