Optimization of cyanobacteria Microcystis aeruginosa extract to improve the yield of Ag nanoparticles with antibacterial property

Abstract

The present study reported the green synthesis of silver nanoparticles (AgNPs) from cyanobacterial blooms Microcystis aeruginosa. The yield of AgNPs was successfully enhanced by optimizing the extraction conditions of algal extract by response surface methodology (RSM). Under the optimal M. aeruginosa extraction conditions (57 °C, pH 4.9, and 30 min), the maximum of AgNPs (19.07 mg/L) was obtained. The surface plasmon resonance (SPR) peak of AgNPs was observed at 430 nm, and AgNPs were well-dispersed spherical with an average size of 6.80 nm in diameter. FTIR analysis showed that the functional groups from M. aeruginosa extract had participated in the synthesis process of AgNPs. In addition, these biosynthetic AgNPs demonstrated excellent antibacterial activity against gram-positive Staphylococcus aureus and gram-negative Escherichia coli. Thus, the current green synthesis method using M. aeruginosa extract can be considered as an eco-friendly and high-efficient approach to synthesizing AgNPs for environmental and biomedical applications.