ON BIOREFINERY OF MEDITERRANEAN ENERGY CROPS GIANT REED AND CARDOON – RATIONAL WAYS FOR CARBOHYDRATE UTILIZATION

摘要

The agro-based lignocellulosics, such as annual crops and perennial herbaceous species (grasses),represent abundant and low-cost feedstocks for biorefinery schemes. Assuming that carbohydrate fraction accountsfor up to 80% of lignocellulosic raw materials, the efficient access and conversion of carbohydrates to value-addedchemical intermediates or final products is a key factor for successful biorefinery commercialization. The biorefineryof two potential Mediterranean energy crops giant reed and cardoon has been studied. Following to pre-definedfractionation scheme with separate utilization of hemicellulose and cellulose portions, the high quality xylose-richsubstrate was produced from both crops by selective one-step hydrolytic conversion of hemicelluloses (basicallycomposed of heteroxylan), yielding 18-22 g of monomeric xylose per 100 g of dry biomass. The residual cellulosewas readily saccharificated by enzymes to fermentable sugars for bio-ethanol production, providing the cellulose-toglucoseconversion of 70-76%. Alternatively, the xylan-free solid residue was used as a source of cellulosic fibers forchemical pulp production. The high purity dissolving grade pulps with alpha-cellulose content of 93-94% wereproduced using advanced sulfur-free technologies.