1. Bulgarian Academy of Sciences
11/04/2019
ADAPTIVE CONTROL OF FED-BATCH PROCESS OF POLY--HYDROXYBUTYRATE (PHB) PRODUCTIONBY MIXED CULTURE
Dr. Maya IGNATOVA
Institute of Control and System Research
Bulgarian Academy of Sciences
Dear colleagues,
I would like to present the process for biodegradable polymer production by mixed culture as an object for control. Two adaptive control algorithm based on General Dynamical Model Approach are demonstrated.
Discussions about applicability of toolbox 'Jobcontrol' for the considered process have to be realized after the presentation.
Prague, October, 9, 2007

2. Process reaction scheme
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Process reaction scheme
In this slide, you can see the scheme of the process. It consists of three reactions - 1, 2 and 3. The intermediate metabolite, lactate, is not the target product. It is used as carbon source for the second biomass growth. The target product, PHB, is produced during the second and third reaction and is proportional to the biomass X2.
The main purpose of the control is to stabilize the lactate concentration in the reactor at an optimal value using the glucose feeding as the control input. Glucose and lactate concentrations are measured on-line.

3. Model of the process 2 1 11/04/2019
As only two variables are available (S and L) on-line, only two parameters could be estimated according necessary conditions for the process (3) observability [2]. We define two new kinetic parameters, 1 and 2. They are production and consumption rates of lactate.

4. Defining a control marker
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Defining a control marker
Estimations of those parameters could be considered as software sensors of those two kinetic parameters.
Their difference could be defined as a marker for recognizing of the process physiological state. The sign of the marker is used for switch on or off the glucose feeding as well as for the change of physico-chemical conditions of cultivation.
Hence, we expect an impulse control of glucose feeding.
 is the control marker

5. The optimal value of lactate is known – by Haldane model
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The optimal value of lactate is known – by Haldane model
L opt
2 MAX
Control algorithms could be derived taking in to account that the relationship between biomass growth and carbon substrate (lactate) is presented by Haldane model. So, an optimal value for lactate concentration could be calculated in this case and the control input – the glucose feed rate is calculated using the following expression: .

6. ADAPTIVE CONTROL SCHEME
3. Adaptive control algorithms based on General Dynamical Model Approach
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ADAPTIVE CONTROL SCHEME + S F +
Adaptive
F controller
Process
model L DO  1
-2
DO*
In the control scheme, two control outputs (glucose and lactate) and two control inputs (DO and glucose feed rate) are shown. The presented new software sensors enriches the process information with on-line recognizing of the culture physiological state. This allows the design of adaptive control which could be considered as optimal one in view of the fact that the feeding of main carbon source (glucose) and physico-chemical parameter (DO) could be automatically controlled following the optimal conditions for each process phase, that is determed by the control marker delta. DO
control
S. Sensors

7. 11/04/2019
In this slide, the reaction of the control scheme is presented. Here you can see both outputs: glucose and lactate, and the control inputs DO and glucose feed rate F.
As can be seen, the control is realized as impulses of glucose feeding and dissolved oxygen concentration. The impulses wide depend of the sign of the marker. When  is negative, the L production has to be stimulated. . When  is positive, L consumption has to be provoked . The production the lactate is stimulated by both - the low value of the dissolved oxygen and glucose feeding. The consumption of the lactate is stimulated by high value of the dissolved oxygen only. The impulses high is calculated by control law shown above.

8. Working program Аcquaint with toolbox 'Jobcontrol' functions
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Working program
Аcquaint with toolbox 'Jobcontrol' functions
Discussions about applicability of toolbox 'Jobcontrol' for control design of the considered process.
Control design applying toolbox 'Jobcontrol‘ ?
Here a draft of our working program is presented. After this presentation we would like to:

9. Our main publications on the topic
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Lyubenova V., M. Ignatova, M. Novak, Т. Patarinska, (2006), Model for Control of Fed-Batch Process for Poly--Hydroxybutyrate (PHB) Production by Mixed Culture of L. Delbrulckii and R. Eutropha, In: International Scientific Conference “Food Science, Techniques and Technologies 2006”, University of Food Technologies Plovdiv, Bulgaria, October, V. LIII(2),
Ignatova M., V. Lyubenova and al. (2007), Indirect adaptive linearizing control of a class of bioprocesses – Estimator tuning procedure, Journal pf Process Control (2007), doi: /j.jprocont
Lyubenova V., M. Ignatova, M. Novak, Т. Patarinska (2007), Reaction rates estimators of Fed-Batch Process for Poly--hydroxybutyrate (PHB) Production by Mixed Culture, Biotechnology&BioE, (Sofia), 21(1) (2007), pp
Ignatova M., V.Lyubenova, (2007), Adaptive control of fed-batch process for poly--hydroxybutyrate production by mixed culture, Proceedings of Bulgarian Academy of Sciences, V. 60 (5), pp
Ignatova M., V. Lyubenova (2007). Control of class bioprocesses using on-line information of intermediate metabolite production and consumption rates, International Conference “Agricultural and Food Sciences, Processes and Technologies”,, Acta Universitatis Cibiniensis, Series E: Food Technology, I.S.S.N , (2007), Sibiu, Romania.
On this slide, my main publications on the topic are shown.

10. Acknowledgments This work was supported by :
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Acknowledgments
This work was supported by :
The joint project in framework of bilateral agreements between Bulgarian Academy of Sciences and Academy of Science of Czech Republic.

11. THANKS FOR YOUR ATTENTION!
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THANKS FOR YOUR ATTENTION!