Organosolv and oxidation pretreatment methods will fractionate the biomass into three distinct process streams. The Acetone -water oxidation process which has been developed in CPERI will be further studied in an effort to make it more efficient, flexible and agnostic so as to be able to pretreat different types of biomass. The use of supercritical CO2, alternative organic solvents and heterogeneous catalysis in a combinatory manner will be evaluated. Controlling the solvent strength, diffusion and acidity of the system will allow the control of the hemicellulose hydrolysis, lignin removal and the reduction of the severity of the process temperature and pressure. This will allow the minimization of inhibitory compounds that reduce the enzymatic process efficiencies. High delignification and hemicellulose hydrolysis, above 90%, coupled with high cellulose pulp recovery and purity, above 85%, will be targeted.
Novel enzymatic tailor-made cocktails optimized specifically towards the maximal performance (>90% sugar conversion) on the cellulosic and hemicellulosic fractions after pretreatment will be developed. Efficient saccharification will provide an almost pure sugar stream that will be used for fermentation processes for the production of omega-3 fatty acids and lactic acid, achieving much higher yields (80-85% of conversion) than reported in the literature when lignocellulosic biomass is used. Coupling the newly developed organosolv process with enzymatic conversion towards chemicals such as lactic acid will yield novel results. Process development will be based on previous work that will guide the decision making. Combining organosolv fractionation eliminating the inhibitors formation with high-performance customized enzymatic cocktails and an efficient fermentation step, will allow for the complete conversion of the sugar-derived fractions to valuable materials and bioactive compounds, boosting the zero waste concept of this project.
Pyrolysis of lignin and enzymatic oligomerization of phenols will be coupled in a cascade process in order to produce monomeric and oligomeric phenols of high added value. Catalysts specially designed for lignin conversion towards phenols will be tested. Mesoporosity will be introduced in highly acidic zeolites such as ZSM-5 to achieve high lignin depolymerization within the mesopores where bulky lignin oligomers have access, and selective conversion towards desirable phenols. Metal impregnation, such as Co, Ni, will be studied as a means to increase selectivity to specific phenols.
Moreover, pyrolysis of cellulose assisted by heterogeneous catalysis, towards anhydrosugars such as levoglucosan and levoglucosenone will help develop a fast highly selective process. Mildly acidic mesoporous materials, based on MCM-41, impregnated with metals in order to increase their selectivity will be studied and the best catalyst will be tested in a continuous unit to yield an anhydrosugars-rich solution that will allow separation studies to take place and also prove the scalability of the process.