Giant Reed (Arundo Donax L.) is one of the most interesting crop for energy production due to the high productivity in less-fertile environments too. Among all the technological options, anaerobic fermentation with oleaginous yeasts for the synthesis of lipids rep- resents the last frontier of biological conversion of ligno-cellulosic biomasses to fuels or to bio-polymers. The chemical composition of biomass (i.e. cellulose, lignin and emicellulose) is a key factor of this process.