CIRCLE aims at demonstrating at industrial scale a first-of-its-kind retrofitted biorefinery for the valorisation of food waste streams and additional biomasses into high-value bio-based chemicals and intermediates, lactic acid (LA) as well as derived products, including polylactic acid (PLA), upgrading and expanding the production capacity of an existing biogas plant. The upgrade proposed will valorise the food waste streams currently processed for biogas production to produce LA ready for downstream high-value applications, including the production of PLA and derived new and higher-value products. The process will take advantage of the existing facility and of the renewable energy (biogas and heat) directly produced, thus making the production highly energy efficient. The proposed technology is highly scalable and replicable as it is designed to be deployed as an ‘add-on’ to existing food waste processing infrastructures. CIRCLE will reach the TRL8 by the end of the project by demonstrating the production of raw LA, which will be then converted into clean lactate salt (CLS) and into industrial and polymer-grade LA (≥ 95-99%). The polymer-grade LA will be in turn polymerized into a recyclable PLA, which can replace fossil-based polypropylene (PP) in a wide range of applications, with a significant impact on GHG emissions and environmental pollution avoidance. The application of bio-based chemicals and intermediates will be demonstrated through the production of a wide portfolio of bio-based products fully compliant with market requirements, such as cover cosmetics products (for CLS and LA), cleaning products (for LA) as well as the automotive, cosmetics and food packaging sectors (for PLA). The new circular value chain is expected to generate €20M of turnover and ca. 50 jobs. Retrofitting the existing biorefinery will allow saving at least 10% of the CAPEX.