Enhancement of Lignin Production from Olive Tree Pruning Integrated in a Green Biorefinery

The green biorefinery concept relies on economically feasible processing to achieve a complete utilization of most lignocellulosic biomass components using green technologies. Among the main component of lignocellulosic biomass, lignin is one of the most interesting components since its aromatic nature makes lignin unique. The study presented here was focused on the enhancement of the organosolv lignin produced from olive wood from the point of view of not only operational conditions but also taking into account the purity and contamination of the obtained lignin. The results showed that the amount of lignin recovered in the liquor was strongly influenced by the process temperature. The ethanol concentration presented the opposite behavior with lignin, reaching high yields at low concentrations. Then, the obtained lignins under optimized conditions were analyzed in order to verify their purity. Almost all the obtained lignins presented hemicellulose contamination but there were differences between the polymerization degree of hemicelluloses and the abundance of hemicelluloses.