Characteristics of the luminous Photobacterium leiognathi from the Andaman and Nicobar Islands seawater as a source of eco-friendly biopolymers and a tool for toxicity analysis

Plastic, a synthetic polymer widely utilized in contemporary industry, poses significant risks to consumers' health and the environment in many ways, with numerous research approaches demonstrating its detrimental effects on human health. Traditional plastic products generally require 100–1000 years to break down in landfills, contaminating nearby water and air. Considering this, the potential marine luminous bacteria was isolated from Andaman Sea to produce eco-friendly bio-polymers which remain largely unexplored. In this research, an indigenous potential bioluminescent bacterial strain, VITJS9, was isolated from marine fish Gazza minuta near Andaman and the Nicobar Islands. The central composite rotational design approach was used to find the optimal growth medium for the isolated potential strain, VITJS9. The strain exhibited maximum growth and luminescence, with optical density values of 4.98 ± 0.14 and relative light unit values of 11.84 ± 0.20. It was identified as Photobacterium leiognathi using 16S metagenomics investigations. MALDI-TOF MS identified the fraction as alkanal monooxygenase, the alpha-chain of luciferase. Lipinski's analysis was used for statistical optimization. The toxicity of heavy metals was evaluated using the isolate. The IC50 values for Cd, Cu, Cr, Zn and Mn after a 15-minute exposure were 1.066, 1.56, 1.91, 3.2 and 5.65 mg L-1 respectively, indicating its potential as a biosensor for heavy metal detection.