Players over the Surface: Unraveling the Role of Exopolysaccharides in Zinc Biosorption by Fluorescent Strain Psd.

Fluorescent strain Psd is a soil isolate, possessing multiple plant growth promoting (PGP) properties and biocontrol potential. In addition, the strain also possesses high Zn biosorption capability. In this study, we have investigated the role exopolysaccharides (EPS) play in Zn biosorption. We have identified that alginates are the prime components contributing to Zn biosorption. Deletion of the gene, which codes for a sub-unit of alginate polymerase, led to a significant reduction in EPS production by the organism. We have also demonstrated that the increased alginate production in response to Zn exposure leads to improved biofilm formation by the strain. In the deletion mutant, however, biofilm formation was severely compromised. Further, we have studied the functional implications of Zn biosorption by strain Psd by demonstrating the effect on the PGP and biocontrol potential of the strain.