Life cycle assessment of VFA production from cheese whey

Growing interest in the circular bioeconomy has encouraged the conversion of agro-industrial side streams into valuable bio-based products. In this context, this thesis assessed the environmental performance of volatile fatty acid (VFA) production from cheese whey, using data from laboratory experiments conducted at the Università Politecnica delle Marche within the ONE EARTH project. The aim was to identify environmental hotspots and opportunities for improvement. An attributional cradle-to-gate life cycle assessment used 1 litre of cheese whey treated as the functional unit, covering the process up to filtered VFA-rich broth. Experimental data and background databases supported the inventory, while the Environmental Footprint 3.1 method assessed impacts across 16 categories. Scenario analyses explored electricity sourcing and inoculum modelling, with animal-feed use providing an external benchmark. Fermentation electricity emerged as the dominant hotspot, contributing approximately 99% of the baseline Single Score. The renewable electricity scenario reduced impacts in 15 of the 16 categories, including a 91% reduction in climate change, although land use increased. In contrast, alternative inoculum inventories had limited effects and did not alter the main findings. Animal-feed use showed lower impacts under the adopted assumptions. However, the pathways fulfil different functions, so this comparison cannot establish their overall environmental preference. Overall, the findings provide an environmental baseline for further process development and highlight the potential of improved energy efficiency and renewable electricity sourcing. Direct energy measurements and pilot-scale evaluation would support a more representative assessment of future performance.