Bio-sorption capacity of cadmium and zinc by Pseudomonas monteilii with heavy-metal resistance isolated from the compost of pig manure

Abstract

The tolerance of Pseudomonas monteilii X1, isolated from pig manure compost, to Cd and Zn, as well as its capacity for biosorption, were investigated. The minimum inhibitory concentrations (MIC) of Cd and Zn for the strain were 550 mg/L and 800 mg/L, respectively. Untargeted metabolomics analysis revealed that organic acids and derivatives, lipids and lipid-like molecules, and organic heterocyclic compounds were the main metabolites. The glyoxylate and dicarboxylate metabolism pathway were significantly enriched under Cd²⁺ stress. The isothermal adsorption and adsorption kinetics experiments determined that the strain had adsorption capacities of 9.96 mg/g for Cd²⁺ and 23.4 mg/g for Zn²⁺. Active groups, such as hydroxyl, carboxyl, and amino groups on the cell surface, were found to participate in metal adsorption. The strain was able to convert Zn²⁺ into Zn₃(PO₄)₂·4H₂O crystal. Overall, this study suggested that Pseudomonas monteilii has potential as a remediation material for heavy metals.

Keywords: Biosorption; Heavy metal tolerance; Pseudomonas monteilii; Untargeted metabolomics.