Isolation, characterization, mathematical modeling and assessment of a novel Photobacterium sp. EAH3, as toxicity biosensor

Marine ecosystems are full of unique microbial phenomena, among them bioluminescence that could be harnessed for different ecological functions. This study was conducted to isolate luminous bacteria and utilize their glowing properties as a potential biosensor for toxicity assessment designs. It is worth noting that this study is the first report on the isolation of an Octopus associated Photobacterium species from Alexandria, Egypt. Based on light intensity, strain Photobacterium sp. EAH3 was selected and identified using 16S-rRNA gene sequencing. The luminescence production was further optimized using experimen-tal. Among eight tested variables, the Plackett-Burman design showed that yeast extract, glycerol, pep-tone, and NaCl were the most important factors affecting luminescence. The central composite design calculated the optimum concentration of these variables in the optimized medium, which enhanced the bioluminescence activity by 1.39 folds. The employment of Photobacterium sp. EAH3 as a biosensor for the toxicity assessment of some solvents, hydrocarbons and heavy metals was examined using biolu-minescence inhibition assay. According to the IC50 results, the highest toxicity values recorded were 0.004 M, 4.15 ppm and 1.4 ppm for isoamyl alcohol, Hg2+ and catechol, respectively. Moreover, our study sheds light on futuristic methodology for monitoring toxicity in real polluted environmental and efflu-ents' samples reflecting its promising efficiency. & COPY; 2022 National Institute of Oceanography and Fisheries. Hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This study isolated luminous bacteria from an Octopus in Alexandria, Egypt, and utilized their glowing properties as a potential biosensor for toxicity assessment. The study identified yeast extract, glycerol, pep-tone, and NaCl as the most important factors affecting luminescence production. The research highlights the significance of monitoring toxicity in real polluted environmental and effluent samples.