title: Development of a system for the on-line measurement of carbon dioxide production in microbioreactors: application to aerobic batch cultivations of Candida utilis.
abstract: We developed and applied a conductometric method for the quantitative online measurement of the carbon dioxide (CO(2)) production during batch cultivations of Candida utilis on a 100-microL scale. The applied method for the CO(2) measurement consisted of absorption of the produced CO(2) from the exhaust gas of the microbioreactor in an alkali solution, of which the conductivity was measured on-line. The measured conductivity change of the alkali solution showed a linear relation with the total amount of CO(2) absorbed. After calibration of the CO(2) measurement system, it was connected to a well of a 96-well microtiter plate. The mixing in the well was achieved by a magnetic stirrer. Using online measurement of the CO(2) production during the cultivation, we show reproducible exponential batch growth of C. utilis on a 100-microL scale. The CO(2) production measurements obtained from the microcultivation were compared with the CO(2) production measurement in a 4-L bioreactor equipped with a conventional off-gas analyzer. The measurements showed that on-line measurement of the CO(2) production rate in microbioreactors can provide essential data for quantitative physiological studies and provide better understanding of microscale cultivations.
authors.affiliation: Dept. of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
authors.forename: Michiel
authors.initials: M
authors.lastname: van Leeuwen
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Heijnen
authors.forename: Han
authors.initials: H
authors.lastname: Gardeniers
authors.forename: Luuk A M
authors.initials: LA
authors.lastname: van der Wielen
authors.forename: Walter M
authors.initials: WM
authors.lastname: van Gulik
mesh_terms: D000332:Aerobiosis; D019149:Bioreactors / Q000382:microbiology*; D015374:Biosensing Techniques / Q000379:methods*; D002175:Candida / Q000254:growth & development / Q000378:metabolism*; D002245:Carbon Dioxide / Q000032:analysis / Q000378:metabolism*; D005285:Fermentation; D009862:Online Systems
chemical_list: D002245:Carbon Dioxide