Formation of Variously Shaped Gold Nanoparticles by Anabaena laxa

Abstract

Anew aspect of this study is the biocatalysis ability of Anabaena laxa—fresh-water strain—which to date has not been studied with respect to the formation of gold nanoparticles. The results of our study have shown that A. laxa is able to form gold nanoparticles (AuNPs) at good yields within 24 h of incubation at all three tested concentrations (0.1, 0.5 and 1 mM) of hydrogen tetrachloroaurate (III). After 24 h, nanoparticles were mostly localized in the growth medium, which significantly facilitates their isolation. However, the elongation of this process is accompanied by their concentration in the exopolysaccharide (EPS) layer of the cyanobacterial cells. There is a correlation between the initial concentration of the Au3+ cations and the formation of AuNPs of various shapes and a size. The comparison of activities of living and deactivated cells indicated that AuNPs were formed more efficiently when metabolically active cyanobacteria were used.