Use of Escherichia coli cloned with genes encoding bacterial luciferase for evaluation of chemical toxicity

A method for evaluation of toxicity of aqueous solutions is described based on the use of genetically engineered Escherichia coli. The genes encoding bacterial luciferase have been cloned from Vibrio harveyi to a deep rough mutant of E. coli under the control of the lac promoter. Light production by this strain has been stabilized by optimizing several parameters having an effect on the gene expression. Toxicity measurements were performed for selected metals and organic solvents to determine the sensitivity of the test strain. Effective concentrations calculated from these measurements show that this method has a sensitivity equal to other normally used methods. The test can be performed using buffers with low ionic strength without any significant change in the stability of the light emitted. Moreover, the method does not necessitate the use of special equipment or skills.