Rapid assessment of heavy metal toxicity using bioluminescent bacteria Photobacterium leiognathi strain GoMGm1

Autor: Murugesan Rajesh Kannan, Narayanan Kalyanaraman, Thirumalaiswamy Vennila, C.M. Ramakritinan, Thillaichidambaram Muneeswaran
Rok vydání: 2021
Předmět:
Zdroj: Environmental Monitoring and Assessment. 193
ISSN: 1573-2959
0167-6369
DOI: 10.1007/s10661-021-08860-2
Popis: Several commercial test kits such as Microtox, LUMIStox, ToxAlert, Aboatox, and ToxScreen have been widely used for toxicity screening. Though this time saving assays offer excellent sensitivity, cost-effectiveness, and accuracy, these commercial assays are limited in terms of real-time monitoring in Indian coastal environment due to warmer temperatures. This necessitates the need to develop a rapid and accurate assay that can be effectively employed for real time monitoring with respect to heavy metals in the Indian coastal waters. With this objective, the present study was conducted by isolating an indigenous luminescent bacterium from the light organs of chordates Gazza minuta which showed higher luminescence in a wide range of temperatures. The isolate could grow well in the temperature of 30 ± 2 °C and withstand temperature up to 35 ± 2 °C. The isolated bacterium was identified as Photobacterium leiognathi GoMGm1 based on 16S rDNA and luxA gene sequences. The suitable growing medium was optimized using central composite rotational design (CCRD) method to obtain optimal growth and luminescence. The optimized medium exemplified the maximal growth and luminescence of P. leiognathi at OD600 nm of 5.78 ± 0.12 and RLU of 12.49 ± 0.43. The isolate was used to assess the toxicity of several heavy metals. The IC50 values of 0.0051, 1.13, 1.37, 3.1, and 6.68 mg L−1 were observed for the Hg, Cr, Cu, Ni, and Zn, respectively, after 15 min of exposure. Results obtained from principal component analysis (PCA) displayed the present assay’s compatibility with other luminescent bacterial assay and commercial Microtox™ assay. Thus, it would the right candidate as an early detection system for heavy metals in aquatic bodies in tropical countries.
Databáze: OpenAIRE
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