University of Hertfordshire

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Original languageEnglish
Pages (from-to)1927-1936
JournalJournal of Chemical Technology and Biotechnology
Early online date22 Jun 2015
Publication statusPublished - 31 Oct 2015


Background: Microbioreactors have recently emerged as novel tools for early bioprocess development. Mixing lies at the heart of bioreactor operation (at all scales), and the successful implementation of micro-stirring methods is thus central to the further advancement of microbioreactor technology. The aim of this study was to develop a micro-stirring method that aids robust microbioreactor operation and facilitates cost effective parallelization.
Results: We developed a microbioreactor with a novel micro-stirring method involving the movement of a magnetic bead by sequenced activation of a ring of electromagnets. The micro-stirring method offers flexibility in chamber designs and we demonstrate mixing in cylindrical, diamond and triangular shaped reactor chambers. Mixing times between the cylindrical and diamond-shaped chamber compared well, with the shortest mixing times in both being 3.4 s. Ease of micro-bubble free priming, a typical challenge of cylindrical microbioreactor chambers, was obtained with diamond shaped chamber. Consistent mixing behaviour was observed between the constituent reactors in a duplex system, and batch and continuous culture fermentation of Staphylococcus carnosus successfully performed.
Conclusion: A novel stirring method using electromagnetic actuation offering rapid mixing and easy integration with microbioreactors was characterized. The gained design flexibility enables fabrication of chambers suitable for microfluidic operation, and a duplex demonstrator highlights potential for cost-effective parallelization. Combined with a previously published cassette-like fabrication of microbioreactors, these advances will facilitate the development of robust parallelized systems for both batch and chemostat bioreactor operation.


© 2015 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.


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