Dark variants of luminous bacteria whole cell bioluminescent optical fiber sensor to genotoxicants

Abstract

A stable dark variant separated fromphotobacterium phosphoreum (A2) was fixed in agar-gel membrane and immobilized onto an exposed end of a fiber-optic linked with bioluminometer. The variant could emit a luminescent signal in the presence of genotoxic agents, such as Mitomyein C (MC). The performance of this whole-cell optical fiber sensor system was examined as a function of several parameters, including gel probe thickness, bacterial cell density, and diameter of the fiber-optic core and working temperature. An optimal response to a model genotoxicant. Mitomycin C, was achieved with agar-bacterial gel membrane: the thickness of gel membrane was about 5 mm; the cell density of bacteria in gel membrane was about 2. 0×10⁷/ml: the diameter of fiberoptic core was 5.0 mm; the working temperature was 25 C. Under these optimized conditions, the response time was less than 10 h to Mitomycin C, with a lower detection threshold of 0.1 mg/L.

Keywords

photobacterium phosphoreum / dark variant / genotoxicant monitoring / fiber-optic sensor

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