A Comprehensive Study on Extracellular Green Synthesis, Antibacterial Activity and Process Design of Metallic Nanoparticles from <i>Botryococcus braunii</i> Microalga

In this study, silver nanoparticle (AgNP), iron-oxide nanoparticle (FeONP) and copper-oxide nanoparticle (CuONP) were synthesized from aqueous extracts of Botryococcus braunii by the biological synthesis method, and the effects of pH, metal salt solution ratio and temperature on MNP diameter were examined statistically. In addition, a process design was made for large-scale production in line with the experimental data obtained. The antibacterial activities of green-synthesized MNPs against several pathogenic bacteria were also investigated. According to the results, optimum green synthesis conditions were determined as high pH, low metal salt content and medium temperature, and the diameters of AgNP, FeONP and CuONP synthesized in these conditions were calculated as 43.46 +/- 6.38 nm, 62.86 +/- 10.08 nm and 70.78 +/- 8.96 nm, respectively. In addition, these synthesized nanoparticles have antibacterial impacts against gram-negative and -positive bacteria. This study shows that B. braunii is a good source for MNP synthesis and the produced MNPs have a good antibacterial effect. The results obtained from this study will be a guide for future studies related to the use of antibacterial effective MNPs in industries such as pharmaceuticals, paints and cosmetics.