Shiitake Capable of Synthesizing Gold Nanoparticles

Gold nanoparticles have many applications in research from cancer therapy all the way to information technology. Various methods have been utilized to synthesize nanoparticles but these are costly and require harmful chemical compounds. In previous studies, several fungi have been found able to reduce gold from auric compounds to form nanoparticles. The medicinal shiitake mushroom (Lentinus edodes) is one of these fungi. This study focuses on examining the ability of shiitake to reduce auric chloride to elemental gold and accumulate nanoparticles in its vegetative part as well as to identify the enzymes involved in the process.

Several methods such as transmission electron microscopy and X-ray fluorescence were used to study the fungal activities. It was revealed that when the fungus was grown submerged in chloroauric acid (HAuCl4), colloidal gold accumulated as electron-dense, spherical particles on the surface as well as inside the fungus' mycelial hyphae. The size of these gold colloids ranged from 5 to 50 nanometers. It was also found that the fungal enzymes laccase, tyrosinase, and Mn-peroxidase were the ones involved in the reduction of auric chloride from chloroauric acid.

Visit http://www.sciencedirect.com/science/article/pii/S0168165614001990 for more on this study.