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 bacterial luciferase reporter gene luxCDABE from Photorhadbus luminescens. In E. coli, this system is limited to compounds that produce oxidative stress. Consequently we designed a system that would detect compounds that do not generate such stress. As proof of concept we choose a commonly used oxidase enzyme, for example, glucose oxidase that oxidises glucose to hydrogen peroxide and gluconolactone. The resultant hydrogen peroxide puts stress onto 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 sensitivity from 2 to 12 mM glucose. We propose that by adding glucose oxidase to the oxidative stress whole cell biosensor the specificity of the oxidative stress response can be increased.