Development of a biosensor using photobacterium Spps. For the detection of environmental pollutants

Bioluminescence is a natural phenomenon exhibited by many organisms, in which energy is spent to emit light. These organisms emit light through an enzymatic reaction between the substrate Luciferin, and an enzyme Luciferase. The Lux operon controls the process of luminescence, which follows the quorum sensing mechanism. We used the idea of bioluminescence to develop a photobiosensor to detect the presence of environmental pollutants. Photobacterium spps. was isolated from the squid and the effect of environmental pollutants was studied in the organism by analyzing the luminescence exhibited by the bacterium in presence and absence of the pollutant. The luminescence was recorded using Perkin Elmer Victor 320. A linear decrease in the luminescence was observed with the gradual increase in the concentration of the tested heavy metals. However, a surprising result was observed in presence of Barium (up to concentration 0.6 mg/ml) where the luminescence was found to increase and decreased with further increase in the concentration. This signifies the ability of the bacterium to sense the presence of the pollutant quantitatively as well as qualitatively. This luminescent property of Photobacterium spps. can be exploited for the development of a photobiosensor. This paper discusses the design of an optical biosensor using fibre optic technique and photodiodes to detect the luminescence and convert it into a measurable signal.