1Department of Chemical Engineering , Iran University of Science and Technology, P.o. Box 16765-163 Tehran, I.R. IRAN
2Department of Biotechnology, School of Engineering, Tarbiat Modares University, Tehran, I.R. IRAN
Mathematical modeling and simulation of microbial Polyhydroxybutyrate (PHB) production process is beneficial for optimization, design, and control purposes. In this study a batch model developed by Mulchandani et al.,  was used to simulate the process in MATLAB environment. It was revealed that the kinetic model parameters were estimated off the optimal or at a local optimal point. Therefore, an optimization program was written using MATLAB codes to estimate those parameters again. It resulted in a significant improvement in the accuracy of Mulchandani’s kinetic model. The batch model was evaluated using two batch experiments performed in this work and also Mulchandani’s batch data when kinetic model parameter values estimated in this work were used. Visual comparisons between the model profiles and experimental data indicate that the model represents the process reasonably. A goodness of fit criterion used in this work and some similar researches proved higher accuracy of Mulchandani’s model using this work’s kinetic parameter values compared to other models. Theoretical model verification was also performed that lead to identification of the possible limitations of the model.
 Mulchandani, A., Substrate inhibition kinetics for growth and production of PHB by Alcaligenes eutrophu, Applied Microbiology and Biotechnology, 30, 11 (1989).
 Anderson,A. J. and Dawes, E. A., Physiology and Ultra structure of Leptothrix discophora SS-1., Archives of Microbiology, 145,126 (1990).
 Dawes E.A., Senior P.J., The role and regulation of energy reserve polymers in microorganisms. Polyhydroxybutyrate., Advances in Microbial Physio-logy, 10, 203 (1973).
 Schlegel, H., Gottschalk,G., and Von Bartha, R., Formation and Utilization of Poly-β-hydroxybutyric Acid by Knallges Bacteria (Hydrogenomonas) Nature, London, 191, 463 (1961).
 Howells, E., Opportunities in Biotechnology for the Chemical industry, Chemistry and Industry,7, 5008 (1982).
 Byrom, D., Polymer Synthesis by Microorganisems: Technology and Economics, Trends in Biotechnology, 5, 246 (1987).
 Brandl,H., Gross, R.A., Lenz, R.W., Fuller, C., Plastics From Bacteria and for Bacteria, Advances in Biochemical Engineering,41, 77 (1990).
 Poirier, et al., Production of Polyhydroxybutyrate in Transgenic plants, Science,256, 520 (1992).
 Leibergesell, M., Hustede, E., Timm, A. and Stein- buchel., A., Fuller, R.C., Lenz, R.W. and Schlegel, H.G., Formation of poly(3-hydroxyalkanoates) by Phototrophic and Chemolithotrophic Bacteria, Archives of Microbiology, 155, 415(1991).
 Bradford, D., Growth and Accumulation of Poly-β-hydroxybutyric Acid by Alcaligenes eutrophus, Honours Thesis, Department of Chemical Engineering, University of Queensland (1992).
 Yoo,S.and Kim,W.S. Cybernetic model for synthesis of Poly-b-hydroxybutyric acid in Alcaligenes eutrophus, Biotechnology and Bioengineering, 43, 1043 (1994).
 Asenjo, J. A. and Suk, IA. S. Kinetics and models for the bioconversion of methane into an intracellular polymer, Poly-b-hydroxybutyrate (PHB). Bio-technology and Bioengineering symposium, 15, 225 (1985).