Quantitation of the Function of a Biofilm Reactor by Magnetic Resonance Imaging

Kevin Nott1, Frank Heese1, Marion Paterson-Beedle2, Lynne Macaskie2 and Laurie Hall1

1 Herchel Smith Laboratory for Medicinal Chemistry, University of Cambridge,

School of Clinical Medicine, University Forvie Site, Robinson Way, Cambridge CB2 2PZ, UK

Tel: +44 (0)1223 336805 / 336807, Fax: +44 (0)1223 336748

ldh11@hslmc.cam.ac.uk, www.hslmc.cam.ac.uk

2 School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK Tel: +44 (0)121 4145889, Fax: +44 (0)121 4145925, l.e.macaskie@bham.ac.uk

ABSTRACT

This study demonstrates that Magnetic Resonance Imaging (MRI) can visualise the growth of biofilm on an inert support matrix, and quantitate the blocking effects caused by precipitation of metal ions from a stream of effluent flowing through the resultant bioreactor. The studies were based on a glass tube (16 mm diameter, 70 mm length) packed with cubes of polyurethane foam coated with Citrobacter sp. biofilm. The bioreactors were challenged with a buffered aqueous solution of lanthanum and/or copper ions plus an organic phosphate source which, in the presence of phosphatase in the biofilm, react together to produce a precipitate of metal phosphate. MRI can distinguish the solid metal phosphate from the surrounding fluid, and velocity maps quantitate the effect of blockage on the flow field through the entire bioreactor. The use of these data to aid the design of an efficient bioreactor is discussed.

Keywords MRI, Citrobacter sp., biofilm, reactor