A Green Fluorescent Protein-based Whole-Cell Bioreporter for the Detectionof Phenylacetic Acid

Abstract

Phenylacetic acid (PA) is produced by manybacteria as antifungal agent and also appears to be anenvironmentaly toxic chemical. The object of this study wasto detect PAA using Pseudomonas putida harboring a reporterplasmid that has a PA-inducible promoter fused to a greenfluorescent protein (GFP) gene. Pseudomonas putida KT2440was used to construct a green fluorescent protein-basedreporter fusion using the paaApresence of PA. The reporter strain exhibited a high level ofgfp expression in minimal medium containing PA; however,the level of GFP expresion diminished when glucose wasaded to the medium, whereas other carbon sources, such assucinate and pyruvate, showed no catabolic repression.Interestingly, overexpression of a paaF gene encoding PAA-CoA ligase minimized catabolic repression. The reporterstrain could also sucesfully detect PA produced by othera useful tool for detecting bacteria producing PAA.