Lignin extraction from hazelnut shells

The tendency to alternative renewable energy sources rapidly increased during a few decades. As a renewable energy source, lignocellulosic biomass (LB) attracts too much attention due to the abundancy, biodegradability, easy to reach, and can be derived various value-added chemicals and products such as methanol, ethanol, hydrogen, acetic acid. It is mainly composed of three components, namely, lignin, cellulose and hemicellulose. In literature, comprehensive studies are showed that cellulose molecules which composed of mainly sugars (glucose) associated with biopolymers synthesis. While cellulose is valorized, the lignin generated biorefinery operations oftenly resulted as treating a lignin as a waste by-product and burned for heat and power supply. However, the valorization of LB, usually requires different types of pre-treatment methods due to the recalcitrance of the components of LB. In order to eliminate this recalcitrance, alkaline pre-treatment method use as a sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH)2) depending on the effectiveness on relatively low lignin content biomass, low sugar degradation and a non-corrosive nature. In addition that, NaOH particularly cleavages ether and ester bonds between lignin-carbohydrate complexes and the ester, carbon-to-carbon bonds in lignin molecules, while Ca(OH)2 mainly removes acetyl groups. The following step referred as "Enzymatic Hydrolysis" and in this case, pretreated and relatively separated parts are enzymatically saccharrified by cellulase enzyme. In this study, for the extraction of lignin from unused raw material named as hazelnut shells (HS) investigated.