Microwave-assisted hydrolysis of giant reed hemicellulose in the presence of Amberlyst-70 as heterogeneous catalyst

Lignocellulosic biomass is an abundant renewable resource that does not compete with the food chain. Biomass conversion to sugars represents the basis of future biorefineries, because sugars can be converted to bio-fuels, bio-chemicals or bio-based materials through fermentative or chemical routes. The present study is focused on the investigation and optimization of the sustainable microwave-assisted heterogeneous hydrolysis of giant reed (Arundo donax L.) in order to convert hemicellulose to xylose, which can be used as substrate for the synthesis of several products. The employment of microwave irradiation together with a recyclable solid acid catalyst, such as Amberlyst-70, could be a sustainable alternative to the hydrolysis of biomass carried out with mineral acids or enzymes. The effects of the main process parameters, such as temperature, catalyst amount and biomass to liquid weight ratio, on reducing sugars yield were investigated. The quantitative conversion of hemicellulose into xylose equal to 96.3 wt% was achieved by optimizing heterogeneous catalysis. The obtained results confirm the possibility of using Amberlyst-70 as solid acid catalyst in an alternative strategy for the biomass hydrolysis, especially in biorefinery processes that require high xylose concentration.