Enhancement in the sensitivity of an immobilized cell-based soil biosensor for monitoring PAH toxicity

A soil biosensor was developed in our previous study using both a recombinant bioluminescent bacterium, GC2 (lac::luxCDABE), immobilized with transparent glass beads within an agar matrix and rhamnolipids, a biosurfactant employed to increase the bioavailability of phenanthrene from contaminated soil. To improve the sensitivity of this biosensor, glass beads of various sizes were tested. The results showed that the detection limit of the biosensor was lowered when smaller-sized glass beads were employed. Further tests showed that the use of glass beads with smaller diameters enhanced the sensitivity of the biosensor, allowing for a more conclusive study on the phenanthrene toxicity present within soils. (C) 2003 Elsevier B.V. All rights reserved.