Kinetic modeling of poly(β-hydroxybutyrate) production and consumption by Paracoccus pantotrophus under dynamic substrate supply

• Published in: Biotechnology and bioengineering Vol. 55; no. 5; pp. 773 - 782
• Main Authors: van Aalst-van Leeuwen, M. A., Pot, M. A., van Loosdrecht, M. C. M., Heijnen, J. J.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 05.09.1997; Wiley
• Subjects: activated sludge process; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; Biotechnology; dynamic growth; Fundamental and applied biological sciences. Psychology; metabolic modeling; Mission oriented research; Paracoccus pantotrophus; PHB; Physiology and metabolism; poly(β-hydroxybutyrate); polymers; Consumption; Culture medium; Growth rate; Ester polymer; Butyrate(hydroxy)polymer; Acetate; Metabolism; Carbon; Kinetic model; Medium effect; Limiting factor; Production; Microorganism culture; Bacteria; Biological accumulation
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/(SICI)1097-0290(19970905)55:5<773::AID-BIT7>3.0.CO;2-8

The objective of the research was to obtain insights into the behavior of microorganisms under feast/famine conditions as often occur in wastewater treatment processes. The response of microorganisms to such conditions is the accumulation of storage polymers like poly(β‐hydroxybutyrate). The research was performed using a pure culture of Paracoccus pantotrophus LMD 94.21. A steady‐state C‐limited chemostat culture was switched to batch mode and a pulse of acetate was added. As long as external substrate (acetic acid) was present, the organism grew and accumulated poly(β‐hydroxybutyrate). After depletion of the external substrate, the stored poly(β‐hydroxybutyrate) was used as growth substrate. Poly(β‐hydroxybutyrate) accumulation was found to be strongly dependent on the growth rate of the organism before the pulse addition of acetate. Poly(β‐hydroxybutyrate) accumulation was correlated to the difference in maximum acetate uptake rate and the acetate required for growth. Based on the interpretation of the experimental results, a metabolically structured model has been set up. This model adequately describes the observed kinetics of the poly(β‐hydroxybutyrate) formation and consumption. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 773–782, 1997.