Bioremediation potential of biofilm forming multi-metal resistant marine bacterium Pseudomonas chengduensis PPSS-4 isolated from contaminated site of Paradip Port, Odisha

Biofilm forming and heavy metal resistant marine bacterial strain Pseudomonas chengduensis PPSS-4 was isolated from the contaminated marine sediment of Paradip Port, Odisha, India. The strain showed biofilm formation up to 100 mg/L of multi-metal [Pb(II), Cr(VI), and Cd(II)] supplementation in the culture medium. Scanning electron microscopy (SEM) showed aggregation of rod-shaped cells in the extracellular polymeric substance (EPS) matrix of biofilm. Confocal laser scanning microscopy (CLSM) exhibited a higher nucleic acid to the alpha-polysaccharide ratio in the biofilm, and the observed thickness was similar to 21 mu m. The metal uptake potential of biofilm culture was higher than planktonic culture both in single and multi-metal solutions. FESEM-EDS analysis revealed the sequestration of multi-metals by bacterial cells and biofilm-EPS. FTIR analysis of bacterial EPS further ensured the interaction of functional groups such as -OH, -NH, and P=O with the metal ions. The maximum removal of Pb, Cr, and Cd by the bacterial biomass was observed at 37 degrees C within 4 h of contact time at pH 6, and 4% salinity for Pb and Cr, and 6% salinity for Cd. The present study revealed that the marine bacterium P. chengduensis PPSS-4 can remove multi-metals, and this bacterium could be efficiently utilized for the remediation of heavy metals in the contaminated environment.

Automated summary

The isolated marine bacterial strain Pseudomonas chengduensis PPSS-4 from contaminated marine sediment of Paradip Port, Odisha, India, showed biofilm formation and resistance to heavy metals. The study demonstrated the high metal removal capacity of the bacterium in both single and multi-metal solutions, making it a potential candidate for efficiently remediating heavy metal contamination in the environment.