WASHING OF HEAVY METAL-CONTAMINATED SOILS USING PYOVERDINE EXTRACTED FROM PLANT GROWTH-PROMOTING BACTERIA PSEUDOMONAS LACTIS AND P. ATACAMENSIS

Soil contamination by metallic trace elements (MTEs) poses a significant environmental challenge, with far-reaching implications for human health and biodiversity. In this context, the exploration of biological methods for chelating MTEs has emerged as a promising, environmentally sustainable approach. Notably, certain metallophores, particularly pyoverdine, demonstrate effective scavenging properties, offering a viable solution. This study involved screening forty-five Pseudomonas isolates for their potential to extract these metals from contaminated soils. Additionally, we monitored the synthesis of various metabolites, including siderophores, indole-3-acetic acid (IAA), ammonia, hydrogen cyanide (HCN), and phosphate solubilization. The purified siderophore fraction was characterized using Fourier Transform Infrared Spectroscopy (FT-IR). Results indicated a notably higher level of siderophore production in P. lactis, P. atacamensis, and Pseudomonas sp. PS11. Particularly, the pyoverdine from P. lactis demonstrated a higher binding affinity for bromine, tin, rhodium, and lead. Our findings conclude that pyoverdine extracted from P. atacamensis exhibited an enhanced capacity for copper ion removal (49.63%), surpassing that of P. lactis (47.65%) and the control agents (EDTA and citric acid, ranging from 43.11% to 27.58%).