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Designing of dual biosensor system for detection of zinc and chromium from contaminated soil using saponin biosurfactant and bioluminescence bacteria

ABSTRACT In this study, a dual biosensor system for detecting chromium (VI) and zinc (II) in contaminated soil including toxic metals has been successfully designed using two strains of immobilised bioluminescent (BL) Escherichia coli Gap and Gfp. Saponinbiosurfactant was used to extract the chromium (Cr6+) and zinc (Zn2+) from soil to the aqueous phase. From obtained results when extracted metals ions were injected into the dual biosensor system, the luminescence level of biosensor decreased dramatically for both zinc and chromium. The concentrations of extracted chromium and zinc are well correlated with metals ions toxicity data achieved by biosensor system. The optimum aeration rate of biosensor system was obtained 30 ml/min. Dual biosensor system may be applied as an in-situ biosensor to detect the toxicity of chromium and zinc in contaminated soil including toxic metals. Therefore, this system can be proposed as a potential alternative to detection of toxic metals in soils.