Establishment of a gaseous pH control concept in microbioreactors

Muhd Nazrul Hisham Bin Zainal Alam, Daniel Schäpper, Krist Gernaey

Research output: Chapter in Book/Report/Conference proceedingBook chapterResearch

Abstract

Existing methods for pH control in bench-scale bioreactor systems often cannot be directly adapted for microbioreactors. This is because microbioreactors are commonly designed to work with constant volumes, operate bubble-free and have no headspace, which technically rules out any possibility of adding acid/base solution for pH control in microbioreactors. This work reports on the establishment of a gaseous pH control concept in microbioreactors where pH control was achieved by dosing of ammonia (NH3, 20 000 ppm) and pure carbon dioxide (CO2) gases to respectively; increase and lower the pH of the reactor content. It encompasses the establishment of an optical pH measurement by means of a fluorescent sensor spot, realization of the necessary gas connections, mixing of gases, and gas-exchange via a thin semi-permeable poly(dimethylsiloxane) (PDMS) membrane. It was shown that addition of NH3 and CO2 gases coupled to a simple on/off controller results in a satisfactorily control performance (pH control accuracy = + 0.1 of the set point value and system responses of a few minutes were achieved) within the dynamic measuring range of the optical sensor spot which is between pH 6 and 8.

Original languageEnglish
Title of host publicationProceedings of 2012 3rd International Conference on Food Engineering and Biotechnology
Number of pages6
Publication date2012
ISBN (Print)978-1-84626-B-004
Publication statusPublished - 2012
EventICFEB 2012: 3rd International Conference on Food Engineering and Biotechnology - Kuala Lumpur, Malaysia
Duration: 5 May 20126 May 2012

Conference

ConferenceICFEB 2012
CountryMalaysia
CityKuala Lumpur
Period05/05/201206/05/2012

Keywords

  • Microbioreactor
  • Optical pH sensor
  • pH control
  • Feedback controller

Cite this

Zainal Alam, M. N. H. B., Schäpper, D., & Gernaey, K. (2012). Establishment of a gaseous pH control concept in microbioreactors. In Proceedings of 2012 3rd International Conference on Food Engineering and Biotechnology