[The Factor Stabilizing the Bioluminescence of PVA-Immobilized Photobacteria].

Immobilization of photobacteria in the cryogel of polyvinyl alcohol (PVA) was carried out. Immobilization was found to result in increased intensity and stability of bioluminescence. The elements determining the stability of bioluminescence were investigated. Selection of the strain was found to be of the highest importance. Among immobilized cells, Photobacterium phosphoreum exhibited the most intense and prolonged light emission, while Vibrio harveyi showed the least one. The technological procedures for cryogenic immobilization of photobacteria were determined. The role of the environment of gel formation in the preservation of the bioluminescence activity was determined. In the gels formed in rich medium for submerged cultivation of photobacteria, almost 100% luminescence activity was preserved, while light emission was considerably prolonged. Bioluminescence intensity of the preparations was shown to depend significantly on pH of the incubation medium. The pH shift to acidic values during prolonged incubation of immobilized cells was shown to be one of the factors of bioluminescence quenching. The stress effects of cryogenic immobilization were found to have an insignificant effect on the temperature profile of bioluminescence. Decreased reduction rate of the luciferase flavin substrate was shown to be a possible reason for bioluminescence quenching.

Photobiosensors containing luminescent bacteria.

The scientific basis for producing luminescent biosensors containing free and immobilized luminescent bacteria is discussed. Modern technologies for engineering target objects, procedures used to immobilize bacteria in different carriers, as well as procedures for integral and specific biodetection of toxins are presented. Data regarding generation and application of biomonitoring for ecotoxicants derived from natural and genetically engineered photobacterial strains are analyzed. Special attention is given to immobilization of photobacteria in polyvinyl alcohol-containing cryogel. The main physicochemical, biochemical, and technological parameters for stabilizing luminescence in immobilized bacteria are described. Results of the application of immobilized photobacterial preparations both during discrete and continuous biomonitoring for different classes of ecotoxicants are presented.

[Biosensors based on the luminous bacteria Photobaterium phosphoreum immobilized in polyvinyl alcohol cryogel for the monitoring of ecotoxicants].

Immobilization of Photobacterium phosphoreum bacteria in polyvinyl alcohol cryogel was performed in order to develop biosensors used for ecotoxicant biomonitoring. The immobilization procedure, storage, and application of the immobilized cells for biomonitoring were optimized. It was shown that the immobilized cells demonstrate significantly higher stability and a longer duration of light emission than free bacteria. A discrete analysis of heavy metals and chlorophenols was conducted using the obtained biosensor samples.