Green synthesis of gold nanoparticles using a glucan of an edible mushroom and study of catalytic activity

► Gold nanoparticles (Au NPs) were synthesized using a glucan isolated from an edible mushroom. ► Glucan acts as both reducing and stabilizing agent. ► Au NPs were characterized by UV-visible, HR-TEM, XRD, FE-SEM and FT-IR analysis. ► Au NPs-glucan bioconjugates functioned as catalyst in the reduction of 4-NP. ► The effect of gold loading and particle size on reduction rate of 4-NP was studied.