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

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. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010

[1]  K. Onogi,et al.  Periodic control of continuous stirred tank reactors—I: The pi criterion and its applications to isothermal cases , 1981 .

[2]  K. Shimizu,et al.  Efficient production of vitamin B12 from propionic acid bacteria under periodic variation of dissolved oxygen concentration , 1996 .

[3]  Dale E. Seborg,et al.  Nonlinear control strategies for continuous fermenters , 1992 .

[4]  S. J. Parulekar.  Forced periodic operations of continuous recombinant cell cultures subject to antibiotic selection pressure , 2001 .

[5]  Kazuyuki Shimizu,et al.  Modeling of the mixed culture and periodic control for PHB production , 2002 .

[6]  H. B. Keller,et al.  NUMERICAL ANALYSIS AND CONTROL OF BIFURCATION PROBLEMS (II): BIFURCATION IN INFINITE DIMENSIONS , 1991 .

[7]  K. Styczen,et al.  Evolutionary search for globally optimal constrained stable cycles , 2006 .

[8]  P. Agrawal,et al.  An algorithm for operating a fed‐batch fermentor at optimum specific‐growth rate , 1989, Biotechnology and bioengineering.

[9]  Walter Borzani,et al.  Response of a continuous anaerobic culture to periodic variation of the feeding mash concentration , 1976 .

[10]  Oliver J. Hao,et al.  Alternating aerobic-anoxic process for nitrogen removal : process evaluation , 1996 .

[11]  Satish J. Parulekar,et al.  Analysis of forced periodic operations of continuous bioprocesses—single input variations , 1998 .

[12]  R. Seydel.  TUTORIAL ON CONTINUATION , 1991 .

[13]  G. Lyberatos,et al.  Periodic optimization of continuous microbial growth processes , 1987, Biotechnology and bioengineering.

[14]  James E. Bailey,et al.  Analytical optimization and sensitivity analysis of forced periodic chemical processes , 1980 .

[15]  A. Ajbar,et al.  Stability and bifurcation of an unstructured model of a bioreactor with cell recycle , 1997 .

[16]  S. J. Parulekar,et al.  Periodic operation of continuous recombinant cultures improves antibiotic selection , 1996 .

[17]  G. Lyberatos,et al.  Effect of cycling on the stability of plasmid‐bearing microorganisms in continuous culture , 1988, Biotechnology and bioengineering.

[18]  Peter A. Wilderer,et al.  Controlled unsteady state processes and technologies - An overview , 1997 .

[19]  Pier Luca Maffettone,et al.  A critical appraisal of the ? -criterion through continuation/optimization , 2006 .

[20]  M. Chidambaram,et al.  Periodic operation of a bioreactor with input multiplicities , 1993 .

[21]  S Pavlou,et al.  Computing operating diagrams of bioreactors. , 1999, Journal of biotechnology.

[22]  D. Dionisi,et al.  Effect of the Length of the Cycle on Biodegradable Polymer Production and Microbial Community Selection in a Sequencing Batch Reactor , 2007, Biotechnology progress.

[23]  Satish J. Parulekar,et al.  Systematic performance analysis of continuous processes subject to multiple input cycling , 2003 .

[24]  E M Abulesz,et al.  Periodic operation of a continuous culture of Baker's yeast , 1989, Biotechnology and bioengineering.

[25]  Xiao Dong Chen,et al.  Comparison of Several Periodic Operations of a Continuous Fermentation Process , 1996 .

[26]  Hector Budman,et al.  Forced modulation of biological processes: A review , 2008 .

[27]  J. A. Kuznecov.  Elements of applied bifurcation theory , 1998 .

[28]  Sergio Bittanti,et al.  Periodic control: A frequency domain approach , 1973 .