Waste Innovative Technological Conversion on Heterogeneous catalysts towards Sustainability (WITCHeS)

The inherent chemical complexity of the lignocellulosic biomass makes it a very attractive source to be recycled and converted into value-added chemicals, representing perhaps the largest challenge facing the 21st century. The main components of lignocellulosic waste are cellulose (40-50%), hemicellulose (15-20%) and lignin (15-30%). While the conversion of cellulose and hemicellulose into platform molecules and biofuels has been widely investigated, lignin waste from biorefineries is frequently used as a low grade-fuel for powering the production plant. Indeed, despite its abundance, lignin conversion has received less attention compared to cellulose and hemicellulose in the biorefinery processes due to the challenges connected with its conversion into high value-added products. However, the valorization of lignin has recently gained significant interest because it provides opportunities for different value-added applications. Furthermore, lignin can be converted into several profitable commodities and fine chemicals, such as fuels, phenols and heterocyclic pharmaceutical relevant compounds. In this frame, the WITCHeS project will be focused on the optimization of efficient and sustainable methods for lignin isolation from agricultural biowaste, aiming to further valorization. In particular, environmentally friendly technologies, alone or combined with green solvents, will be applied either for lignin extraction and depolymerization or for its conversion into valuable compounds. The biomass delignification provides a cellulose-rich solid residue that can be converted into chemicals and fuels through chemo- or biocatalysis, and lignin in the liquid fraction, i.e. the starting material for the project targets. The acid soluble lignin will be fractionated to afford phenolic monomers, whereas the acid-insoluble fraction will be recovered by precipitation and treated through a depolymerization step. The platform monomers thus recovered will be further catalytically converted into biosolvents, biofuels and bioactives. Hierarchical multi-site heterogeneous catalysts will be designed and synthesised ad hoc to address the demand of the project. Enabling technologies for process intensification will be exploited, and the sustainability of the processes developed within the WITCHeS project will be assessed with Life Cycle Analyses, aiming to design a suitable pilot plant for the valorization of all the components of lignocellulosic biomass waste. The positive impacts will involve different sectors: post harvesting phase of agricultural production, lignocellulose pretreatment, biorefineries for the production of chemicals and fuels. If granted, WITCHeS paves the way for the development of new protocols for the development of an integrated multiproduct biorefinery through the valorisation of all the biomass components to biofuels and marketable products, in the newly raised international circular economy scenario.