Green Synthesis of Silver Nanoparticles Using Different Extracts of Spirulina platensis: A Study on Antimicrobial Properties

The green synthesis of nanoparticles is popular due to its efficiency, cost-effectiveness, and environmental sustainability. This study investigated the biosynthesis of silver nanoparticles using Spirulina platensis extracts and their antimicrobial properties. The experiment was a two-factor factorial design with three replications, examining different extracts (supernatant, nano supernatant, water extract, nano water extract, ethanol extract, nano ethanol extract) and bacteria (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, Xanthomonas campestris, Erwinia amylovora). The water extract of Spirulina was prepared by boiling the Spirulina powder in water at ۱۰۰°C, while the ethanol extract was prepared by soaking the Algae powder in ethanol at room temperature for ۲۴ hours. Nanoparticles were characterized using UV-VIS spectrophotometry, X-ray diffraction (XRD), scanning electron microscopy (FESEM), energy dispersive spectrometry (EDS), and Fourier transform infrared spectroscopy (FTIR). The nanoparticles were crystalline and spherical, with sizes ranging from ۲۲-۱۰۴ nm (supernatant), ۲۶-۵۸ nm (water extract), and ۵۸-۹۳ nm (ethanol extract). Antimicrobial activity was assessed by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Silver nanoparticles from Spirulina extracts showed lower MIC and MBC than non-nano extracts, with the supernatant having the lowest values. Erwinia amylovora was the most sensitive strain. The study suggests that algae extracts can effectively reduce silver ions to form nanoparticles, highlighting the potential of Spirulina platensis silver nanoparticles as antimicrobial agents.

Keywords:

Biosynthesis , X-ray diffraction , FTIR , MIC , MBC