Bacterial-mediated synthesis of copper nanoparticles using Pseudomonas aeruginosa and Escherichia coli, and evaluation of antimicrobial activity

Copper is a promising metal for nanoparticle production due to its important physiological role and antibacterial capability. The aim of this study was to evaluate the ability of Escherichia coli and Pseudomonas aeruginosa to biosynthesize copper nanoparticles (CuNPs) both extracellularly and intracellularly, and to determine the antimicrobial potential of CuNPs derived from P. aeruginosa against Staphylococcus aureus , E. coli , Candida albicans and Candida tropicalis. Among the synthesis conditions tested, the optimal condition was extracellular synthesis with P. aeruginosa (ATCC 27853) in a 1:1 (v/v) ratio, with an incubation period of 72 h. The CuNPs synthesized were spherical in shape, with a size of 16.2 ± 3.5 nm. The CuNPs demonstrated significant activity against Gram-positive pathogenic bacteria and unicellular fungi. Among the microorganisms analyzed, CuNPs showed the greatest antimicrobial activity against S. aureus , followed by C. albicans and C. tropicalis . The CuNPs obtained through P. aeruginosa biosynthesis are promising candidates for functionalization with molecules that could enhance their microbicidal power.