Isolation ; characterization and valorization of hemicelluloses from Aristida pungens leaves as biomaterial

Abstract : Aristida pungens, a perennial grass widely distributed on the Algerian arid regions, may potentially be the source of raw cell wall material to promote a local development in North Africa. Hemicelluloses, the main matrix cell wall polymers of this species were isolated from leaves with 14% KOH aqueous solution, characterized and converted as plastic material. The extraction procedure yielded two hemicellulose fractions (A and B) accounting for 3.5 and 10.1% of the starting leaf material, respectively. GC and13C NMR showed the presence of xylose as the main component with arabinosyl residues. Both analyses indicate that hemicelluloses from A. pungens leaves are arabinoxylans. Arabinoxylans were transformed into hydrophobic plastics by grafting of lauroyl chloride. The resulting materials were characterized by FT-IR and1H NMR spectroscopies, with both mechanical and thermogravimetric analysis.