A multi-channel continuous toxicity monitoring system using recombinant bioluminescent bacteria for classification of toxicity

Abstract

A multi-channel system for continuous toxicity monitoring and classification of toxicity was developed based upon a previously developed two-stage minibioreactor system. The multi-channel system consists of a series of a two-stage minibioreactor systems connected by a fiber optic probe to a luminometer. Each channel was used for cultivating different recombinant bacterial strains, such as TV1061 ( grpE::luxCDABE), DPD2794 ( recA::luxCDABE), and DPD2540 ( fabA::luxCDABE), which are induced by protein-, DNA-, and cell membrane damaging-agents, respectively. GC2 ( lac::luxCDABE) is a bacterium expressing bioluminescence constitutively, which shows a reduction in its light level as cellular toxicity increases. Artificial wastewater samples were made by combining toxic chemicals, including Mitomycin C (a representative DNA damaging agent), phenol (a representative protein damaging agent), and cerulenin (a representative cell membrane damaging agent), and injecting this sample into each channel in order to simulate the detection of toxicity for mixed chemical samples. Each channel showed a specific bioluminescent response due to the toxic chemicals contained in the sample wastewater, while GC2 showed a general response to cellular toxicity. By using this multi-channel continuous toxicity monitoring system, classification of toxicity in field samples was found to be possible.