Abstract
The widespread use of agricultural chemicals, such as pesticides and fertilizers, has caused imbalances in agricultural soil. The use of several alternative methods (such as bio-fertilizers) has been suggested. Recent studies have focused on the application of microbial products instead of microbial cells to enhance plant growth. The present study aimed to investigate the effects of pyocyanin (produced as a secondary metabolite by Pseudomonas aeruginosa) on the chemical and physical properties of agricultural soil. Two plants, Lens culinaris and Eruca sativa, were utilized in the study. Based on the results, soil treatment with pyocyanin caused significant increase in some nutrients and minerals such as magnesium, chlorine, and iron, levels of which rose gradually with increasing pyocyanin concentration in the soil from both plants. In contrast, a gradual decline in levels of certain heavy metals, such as copper, lead, manganese, and boron, were observed, and the highest concentrations were reported in the control samples. Positive correlation was observed between electrical conductivity and hydrogen ion concentration in the soil, both of which decreased gradually with increasing pyocyanin concentration in the soil from both plants. Moreover, the P. aeruginosa strain studied herein showed significant antimicrobial activity against plant pathogenic fungi and bacteria. Overall, the study proved the positive interplay between pyocyanin and environmental factors that affect the development of plants, making it an ideal target for extended future research according to its environmental and agricultural significance.