Construction of a modified mini-Tn5 luxCDABE transposon for the development of bacterial biosensors for ecotoxicity testing

A mini-Tn5 transposon was modified to introduce a promoterless luxCDABE cas sette from Vibrio fischeri into environmentally relevant bacterial strains in order to develop bioluminescence-based biosensors for toxicity testing. The mini-Tn5 luxCDABE transposon was chromosomally integrated downstream fr om an active promoter into two Pseudomonas strains (Pseudomonas fluorescens 8866 and Pseudomonas putida F1). Characterisation of the bioluminescent tr ansconjugants demonstrated that the transposon integration was stable and h ad no effect on growth rate. Both P. fluorescens 8866 Tn5 luxCDABE and P. p utida F1 Tn5 luxCDABE were used to assess the toxicity of standard solution s (Cu, Zn and 3,5-DCP) as well as Cu- and 3,5-DCP-spiked groundwater sample s. They were successfully used for bioluminescence-based bioassays and the potential value of using different bacterial biosensors for ecotoxicity tes ting was shown. (C) 2001 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.