- G. Birol, C. Undey and A. Cinar, A Modular Simulation Package for Fed-batch Fermentation:
Penicillin Production, Computers and Chemical Engineering, 26(11), 1553-1565, 2002.
Simulation software based on a detailed unstructured model for penicillin production in a fed-batch
fermentor has been developed. The model extends the mechanistic model of Bajpai and Reuss by
adding input variables such as pH, temperature, aeration rate, agitation power, and feed flow rate of
substrate and introducing the CO2 evolution term. The simulation package was then used for monitoring
and fault diagnosis of a typical penicillin fermentation process. The simulator developed may be used for
both research and educational purposes and is available at the web site: http://www.chee.iit.edu/~control/software.html.
- G. Birol, C. Undey, S. J. Parulekar and A. Cinar, A Morphologically Structured Model for
Penicillin Production, Biotechnology and Bioengineering, 77(5), 538-552, 2002.
A morphologically structured model is proposed to describe penicillin production in fed-batch cultivations.
The model accounts for the effects of dissolved oxygen on cell growth and penicillin production and
variations in volume fractions of abiotic and biotic phases due to biomass formation. Penicillin production
is considered to occur in the subapical hyphal cell compartment and to be affected by availability of glucose
and oxygen. As it stands, the model provides a wide range of applicability in terms of operating conditions.
The model has been tested for various conditions and has given satisfactory results. A series of glucose
feeding profiles have been considered to demonstrate the capabilities of the proposed model. It is concluded
that the model may be valuable for the interpretation of experimental data collected specifically for metabolic
flux analysis during fed-batch cultivation because the elements of measured specific production rates are
determined from measurements of the concentrations of the components and their mass balances. The
proposed model may be further used for developing control strategies and model order reduction algorithms.
- C. Undey and A. Cinar, Statistical Monitoring of Multistage, Multiphase Batch Processes,
IEEE Control Systems Mag., 22(5), 40-52, 2002.
In this study, an MSPM framework for multistage multiphase processes was proposed where pharmaceutical
granules production was used as a case study. Local models were proven to be advantageous when different
phases exist in process stages and when precise phase separation is crucial. Online SPM was performed
through different AHPCA models, since stage-wise continuity did not exist in variable readings. Overall process
monitoring was performed using super-level models based on a consensus matrix to identify localized faults in
process stages/phases. This identification provides a means of decreasing the time required for the assessment
of historical batch process data as well as newly completed batches. The whole procedure can also be
integrated with a knowledge-based system to include explanations about the diagnostics.
- I. Birol, C. Undey, G. Birol and A. Cinar, A Web-Based Simulator for Penicillin Fermentation,
Intl. Journal of Engineering Simulation, 2(1), 24-30, 2001.
A web-based dynamic simulator of penicillin production in a fed-batch bioreactor has been developed. An
unstructured mathematical model previously developed in our laboratory was used to simulate the system dynamics.
The user interface is written as web based application to enable users to run “virtual experiments" to test the
effects of initial conditions and operating parameters on system dynamics for monitoring, diagnosis and control
studies. The software is intended to be used in academic education and research as well as in industrial on-the-job
training. The application is available on http://www.chee.iit.edu/~control/PenSim/v1.0/.