Lignocellulose biorefining through lignin depolymerization
Lignin mono/oligomers represent valuable chemicals for green chemistry, as well as purified cellulose and hemicellulose fractions. Currently, there are no methods available that would offer an efficient fractionation of lignocellulose into such valuable intermediate substances. Lignin depolymerisation and extraction is the most logical first step in a biorefining approach, which can be achieved through several different delignification methods. Understanding the mechanism of lignin depolymerization is a goal which has not been fully achieved to date, and it is only possible by thorough analysis of the released monomers and oligomers. Our investigations focus on the pretreatment and fractionation steps, to separate and extract relatively pure streams of intermediates, especially high purity lignin, but also cellulose and hemicellulose fractions. Extraction of clean intermediates and their characterization are the most important steps to provide knowledge on the behavior of the main biomass components during processing and enable rationale design of biorefining processes. This research project focuses on the use of organosolv fractionation (with and without heterogeneous catalysis), hydrothermal treatment, and catalytic lignin depolymerization into monomers (cyclic alkanes and aromatics) as means to obtain valuable platform chemicals from local agricultural and forestry residues.