Membrane-aerated microbioreactor for high-throughput bioprocessing.

TitleMembrane-aerated microbioreactor for high-throughput bioprocessing.
Publication TypeJournal Article
Year of Publication2004
AuthorsZanzotto, A, Szita, N, Boccazzi, P, Lessard, P, Sinskey, AJ, Jensen, KF
JournalBiotechnol Bioeng
Volume87
Issue2
Pagination243-54
Date Published2004 Jul 20
ISSN0006-3592
KeywordsAcetates, Algorithms, Bioreactors, Chromatography, High Pressure Liquid, Computer Simulation, Densitometry, Dimethylpolysiloxanes, Escherichia coli, Fermentation, Fluorescent Dyes, Formates, Glass, Glucose, Hydrogen-Ion Concentration, Kinetics, Lactic Acid, Membranes, Artificial, Molecular Probe Techniques, Nanotechnology, Oxygen
Abstract

A microbioreactor with a volume of microliters is fabricated out of poly(dimethylsiloxane) (PDMS) and glass. Aeration of microbial cultures is through a gas-permeable PDMS membrane. Sensors are integrated for on-line measurement of optical density (OD), dissolved oxygen (DO), and pH. All three parameter measurements are based on optical methods. Optical density is monitored via transmittance measurements through the well of the microbioreactor while dissolved oxygen and pH are measured using fluorescence lifetime-based sensors incorporated into the body of the microbioreactor. Bacterial fermentations carried out in the microbioreactor under well-defined conditions are compared to results obtained in a 500-mL bench-scale bioreactor. It is shown that the behavior of the bacteria in the microbioreactor is similar to that in the larger bioreactor. This similarity includes growth kinetics, dissolved oxygen profile within the vessel over time, pH profile over time, final number of cells, and cell morphology. Results from off-line analysis of the medium to examine organic acid production and substrate utilization are presented. By changing the gaseous environmental conditions, it is demonstrated that oxygen levels within the microbioreactor can be manipulated. Furthermore, it is demonstrated that the sensitivity and reproducibility of the microbioreactor system are such that statistically significant differences in the time evolution of the OD, DO, and pH can be used to distinguish between different physiological states. Finally, modeling of the transient oxygen transfer within the microbioreactor based on observed and predicted growth kinetics is used to quantitatively characterize oxygen depletion in the system.

DOI10.1002/bit.20140
Alternate JournalBiotechnol Bioeng
Citation Key157
PubMed ID15236254