Holistic development of chemical and biological catalysis approaches for the conversion of waste renewable resources into high value-added molecules

The intensive exploitation of fossil raw materials to produce fuels and building blocks of current industrial production has determined several critical issues. Biomass represents a promising alternative to fossil sources and biorefineries assume a central role, leading to the conversion of biomass into chemicals, intermediates, materials and fuels. Third-generation biomasses and wastes, mainly composed of cellulose, hemicellulose, lignin and bioactive compounds, can be converted into valuable bio-products and bio-fuels. The exploitation of each fraction of the feedstock is fundamental to increase the sustainability. Since cellulose, hemicellulose, lignin and exctratives require specific reaction conditions for their conversion into bio-products and bio-fuels, the cascade multi-step approach could ensure the highest valorisation of each biomass component. The main purpose of this research project is to design, investigate and optimise the conversion of different wastes, such as defatted wheat bran, pine nut shells and sewage scum to triglycerides, citric acid and carotenoids through an innovative approach based on the synergistic combination of chemical and biological catalysis. Firstly, the chemical characterisation of each biomass will be carried out. Tailored pretreatment and/or fractionation approaches will be investigated to extract bioactive compounds for subsequent exploitation. Chemical and enzymatic catalysis will be optimised to valorise both polisaccarides and lignin. Homogeneous acids and cellulolytic mixtures will be evaluated for the hydrolysis reaction. The main reaction parameters will be optimised by a chemometric approach. The obtained hydrolysates will be used as a substrate for the fermentation of oleaginous microorganisms to produce target molecules and the process parameters will be optimised. Ligninrich residues collected after the pretreatment or the hydrolysis will be valorised through the synthesis of aromatics, activated carbons, resins or functionalised materials by implementing (thermo)chemical or biological approaches. The project involves the implementation of LCA studies to evaluate the environmental and economic sustainability of the optimised processes.