Natural lignin, as contained in plants, is fundamentally altered with regard to its chemical structure and properties upon pulping of wood or other biomass processing (Berlin and Balakshin, 2014). The products of these conversions, technical lignins, have only rather limited resemblance to native lignins – this is why the distinction between technical and native lignins is made. Technical lignins need to be retrieved from complex products mixtures, so-called “black liquors”, which also contain other components, such as process chemicals, salts and other inorganics, degradation products from lignin and carbohydrates (Niemelä and Alén, 1999).
Lignin isolation from their production matrices reduces or eliminates interference from non-lignin constituents and thus plays a crucial role in lignin characterization. ALICE offers several approaches for the isolation and purification of lignin from spent pulping liquors generated in the kraft and sulfite pulping processes as well as from other biorefinery streams: precipitation, ultrafiltration and accelerated solvent extraction.
1) Berlin, A. & Balakshin, M. (2014) Industrial Lignins: Analysis, Properties, and Applications. In: Bioenergy Research: Advances and Applications, Chapter 18, pp. 315-336. doi: 10.1016/B978-0-444-59561-4.00018-8
2) Niemelä, K. & Alén, R. (1999) Characterization of Pulping Liquors. In: Analytical Methods in Wood Chemistry, Pulping, and Papermaking. Sjöström, E. & Alen, R. (eds.). Berlin, Heidelberg: Springer Berlin Heidelberg, pp. 193-231. doi: 10.1007/978-3-662-03898-7_7