title: Quantification of the oxygen uptake rate in a dissolved oxygen controlled oscillating jet-driven microbioreactor.
abstract: BACKGROUND
  Microbioreactors have emerged as a new tool for early bioprocess development. The technology has advanced rapidly in the last decade and obtaining real-time quantitative data of process variables is nowadays state of the art. In addition, control over process variables has also been achieved. The aim of this study was to build a microbioreactor capable of controlling dissolved oxygen (DO) concentrations and to determine oxygen uptake rate in real time.
  
  
  RESULTS
  An oscillating jet driven, membrane-aerated microbioreactor was developed without comprising any moving parts. Mixing times of ∼7 s, and kLa values of ∼170 h-1were achieved. DO control was achieved by varying the duty cycle of a solenoid microvalve, which changed the gas mixture in the reactor incubator chamber. The microbioreactor supported Saccharomyces cerevisiae growth over 30 h and cell densities of 6.7 gdcwL-1. Oxygen uptake rates of ∼34 mmol L-1h-1were achieved.
  
  
  CONCLUSIONS
  The results highlight the potential of DO-controlled microbioreactors to obtain real-time information on oxygen uptake rate, and by extension on cellular metabolism for a variety of cell types over a broad range of processing conditions. © 2015 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
authors.affiliation: Department of Biochemical Engineering University College London Bernard Katz Building, Gordon Street London WC1H 0AH UK.
authors.forename: Timothy V
authors.initials: TV
authors.lastname: Kirk
authors.affiliation: Department of Biochemical Engineering University College London Bernard Katz Building, Gordon Street London WC1H 0AH UK.
authors.forename: Marco Pc
authors.initials: MP
authors.lastname: Marques
authors.affiliation: Department of Biochemical Engineering University College London Bernard Katz Building, Gordon Street London WC1H 0AH UK.
authors.forename: Anand N Pallipurath
authors.initials: AN
authors.lastname: Radhakrishnan
authors.affiliation: Department of Biochemical Engineering University College London Bernard Katz Building, Gordon Street London WC1H 0AH UK.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Szita
keywords: Saccharomyces cerevisiae; microbioreactor; microfluidics; mixing; oxygen control; oxygen uptake rate