A panel of stress-responsive luminous bacteria for the detection of selected classes of toxicants

A panel of bacteria, each genetically engineered to respond by increased luminescence to a different type of environmental stress, is presented. Members of the panel were shown to be sensitive to several groups of chemicals including phenols, halomethanes and several oxidants. The increase in light emission depended upon toxicant concentration and could, thus, be used to calculate a characteristic value, EC₂₀₀, designating the sample concentration causing a two-fold luminescence induction. In almost all cases, EC₂₀₀ values were lower than the corresponding Microtox® EC₅₀ values, indicating a generally higher sensitivity. One of the panel members, DPD2794, a designated DNA-damage sensor, responded within 2 h to the presence of genotoxicants, including metabolically activated nitropropane. It is suggested that these or similarly constructed strains can be used for the rapid and sensitive detection of potentially toxic and genotoxic pollutants and that the concept of genetically engineering a panel of microbial toxicity sensors can readily be implemented for environmental monitoring.