Upgrading anaerobic digestion by cascade fermentation coupled with biogas-based biopolymer production
Food waste (FW) and plastic pollution represent two of the most relevant environmental, economic and societal problems in this XXI century. Anaerobic digestion (AD) of FW linked with biogas bioconversion into biopolymers constitute a sustainable route to valorise the enormous untapped potential of FW. However, the full-scale implementation of FW-AD biogas based biorefineries is still limited by the need to enhance stability and prevent inhibition during FW-AD and to overcome the CH4 mass transfer and biological limitations encountered in methanotrophic processes. UP-GRAD aims at upgrading the performance and stability of FW-AD by engineering a novel 2-stage lactate-based AD process coupled with the development of innovative cost-competitive strategies for improving biogas valorisation as a feedstock for the synthesis of tailor-made, high-quality, marketable biopolymers. In this context, UP-GRAD will focus on the enrichment of both industrially robust hydrolytic-acidogenic lactate fermenting inocula and mixed biopolymer-accumulating methanotrophic consortia, and on the optimisation of integrated AD processes and novel high mass transfer nanobubble bioreactors. State-of-art molecular assays devoted to bringing a deeper understanding of the ecological factors tuning metabolic pathways and performance, and of the structure and functionality of the communities involved in the hydrolytic-acidogenic, methanogenic and methanotrophic stages will be conducted during an academic secondment. In addition, a techno-economic analysis and technology-uptake roadmap will be performed during a secondment in an international FW management company. UP-GRAD will apply a cross-disciplinary approach, involving environmental engineering, biochemistry, microbiology, ecogenomics, transcriptomics, bioinformatics and economics, allowing the candidate to create, disseminate and apply a new knowledge that will foster practical solutions for next-generation AD and flexible biogas biorefineries.