Green synthesis of silver nanoparticles from organic matter collected via skimmer from the cultivation of the microalga Nannochloropsis oceanicAuthor: Andressa Coimbra Pereira (Currículo Lattes)
Advisor: Dr. José Monserrat
Abstract
The development of new methods for synthesizing silver nanoparticles (AgNP) that are more environmentally friendly has attracted considerable attention in recent years, with green synthesis—particularly biological approaches—leading these emerging strategies. Microalgae are fast-growing photosynthetic organisms that produce a wide range of compounds capable of reducing ionic silver into AgNP, making them a lower-impact alternative. AgNP are primarily applied as antimicrobial agents, serving as an alternative to antibiotics due to the well-established antimicrobial properties of silver. Therefore, in this study, AgNP were synthesized for the first time using dissolved organic matter (DOM) collected by a foam fractionator (skimmer) from the culture of Nannochloropsis oceanica, acting as a reducing and stabilizing agent in the synthesis, which was monitored through UV-Vis absorbance spectra. The generated AgNP were evaluated using Transmission Electron Microscopy, showing average sizes ranging from 11.89 ± 6.33 to 27.55 ± 8.41 nm. Litesizer analysis revealed a hydrodynamic diameter of 263.82 ± 4.89 nm, a polydispersity index of 0.178, and a zeta potential of -20.41 ± 0.32 mV. The DOM was also analyzed via Fourier Transform Infrared Spectroscopy (FTIR), in addition to microbiological assays for Minimum Inhibitory Concentration (MIC) against Acinetobacter baumannii, Pseudomonas aeruginosa, Vibrio coralliilyticus, and Staphylococcus aureus, as well as growth kinetics and biofilm (inhibition and disruption) assays in A. baumannii, demonstrating that the use of DOM is a viable approach, resulting in a high-value-added biotechnological product.
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