COMPLETE VALORISATION OF GIANT REED: INTEGRATED EXPLOITATION OF HEMICELLULOSE, CELLULOSE AND LIGNIN FRACTIONS TOWARDS VALUABLE BIO-BASED PRODUCTS ADOPTING GREEN PROCESS CONDITIONS

The economic sustainability of modern biorefinery models is strongly affected by the cost and the availability of raw materials. In this perspective, the exploitation of low or negative value biomasses and the complete valorisation of all their fractions represent crucial strategies to favour the development of 2nd-generation biorefineries. This study developed an innovative and integrated biorefinery process based on the complete and sustainable valorisation of cellulose, hemicellulose and lignin fractions of the non-food crop giant reed (Arundo donax L.). Giant reed is a promising low-cost and perennial biomass able to grow on marginal, contaminated or underutilised lands and it is characterised by high production yield, high carbohydrates content and low input management systems. In the first step, microwave-assisted FeCl3-or Amberlyst-70-catalysed hemicellulose conversion to xylose or furfural was optimised. In the second step, the same catalytic approaches were adopted and optimised for the cellulose conversion to glucose or to levulinic and formic acids. As an alternative, the enzymatic hydrolysis of cellulose to glucose was studied. The obtained sugar-rich hydrolysates were converted by fermentation to bio-oil which was used to produce new generation biodiesel. Finally, the remaining lignin-rich solid residue was used to produce activated carbon for the CO2 adsorption.