An oxidative stress-responsive biosensor: responses to hydrogen peroxide generated by an extracellular enzyme

The promoter region of the katG gene of Escherichia coli was fused to the b acterial luciferase reporter gene luxCDABE from Photorhadbus luminescens. I n E. coli, this system is limited to compounds that produce oxidative stres s. Consequently we designed a system that would detect compounds that do no t generate such stress. As proof of concept we choose a commonly used oxida se enzyme, for example, glucose oxidase that oxidises glucose to hydrogen p eroxide and gluconolactone. The resultant hydrogen peroxide puts stress ont o the whole sensor and results in an increase in luminescence over time. We found that the system was specific for glucose and had a range of sensitiv ity from 2 to 12 mM glucose. We propose that by adding glucose oxidase to t he oxidative stress whole cell biosensor the specificity of the oxidative s tress response can be increased. (C) 2001 Elsevier Science Inc. All rights reserved.