Extracellular biosynthesis of gold nanoparticles using sugar beet pulp

Sugar beet pulp was used as redactor agent for the synthesis of gold nanoparticles. The method developed is environmentally friendly and allows control of nanoparticles shapes by changing the initial pH value of aqueous HAuCl4 solutions. At low initial pH values, polygonal nanoparticles were obtained, mainly triangular and hexagonal shapes. Increasing the pH value, nanorods together with polygonal nanoparticles were produced. At higher initial pH, gold nanowires were formed. Gold biosorption took place at long reaction time, especially at low pH. This procedure could be useful to remove or recover metals from aqueous wastes. The synthesis of other metallic nanostructures such as silver and platinum could be achieved following a similar procedure.