Various Shapes of Gold Nanoparticles Synthesized by Glycolipids Extracted from Lactobacillus casei

Abstract

Gold nanoparticles have particular properties distinct from bulk gold crystals. The gold nanoparticles are used in various applications in optics, catalysis, and drug delivery. Although many reports on microbial synthesis of gold nanoparticles have appeared, the molecular mechanism of gold nanoparticle synthesis in microorganisms is unclear. Previously we reported that the amounts of diglycosyl diacylg-lycerol (DGDG) and triglycosyldiacylglycerol (TGDG) bearing unsaturated fatty acids were much reduced after formation of gold nanoparticles. DGDG purified from L. casei induced the synthesis of gold nanoparticles in vitro. These results suggested that glycolipids, such as DGDG, play important roles in reducing Au(III) to Au(0). In this paper, we reported that the concentration change of DGDG induced various shapes of gold nanoparticles in vitro. Our work will lead to the development of novel and efficient methods to synthesize metal nanoparticles using microorganisms.