Insights from an extensive multi-step multi-stakeholder engagement in circular bio-based economy.

Background: The goal of achieving a net-zero emissions European economy by 2050 requires a shift from linear fossil-based to circular bio-based systems. However, this transition relies on societal transformations, cutting-edge technologies, and multi-actor processes, which in turn require new economic frameworks and policy priorities. This study bridges the gap between literature and circular bio-based economy (CBBE) practice by presenting the results of stakeholder engagement activities where the barriers identified in the literature were discussed, ranked and validated. Methods: Adopting a three-step approach, including a focus group, interviews, and a final survey, we present a list of 31 barriers under six different clusters: cultural, economic, environmental, governance, structural, and technical hindering the transition to a CBBE. Results: The literature findings validated through stakeholder engagement underline that the transition requires structural and governance changes to steer the current economic model to a more circular and sustainable one. The most prominent barriers include: Consumer confusion and lack of trust due to generic sustainability claims and the proliferation of certification schemes and labels; High investment costs and risks for establishing circular bio-based industries; Concerns over (local) biomass feedstock availability within the limits of carrying capacity; Regulatory complexities and lack of support for the transition at the government level; Lack of harmonized waste collection systems and infrastructure and Incompatible and/or insufficient infrastructure capacity for EoL product collection, transportation, storage and management. Conclusions: Stakeholder involvement is a critical element of the transition to CBBE, to bridge the gap between scientific advancements and practical implementation. This study aims to identify the most prominent barriers to the CBBE transition with an extensive stakeholder engagement strategy with representatives from the construction, chemicals, plastics, and textile sectors. The findings in this study are expected to feed into the further development of policy recommendations to overcome these barriers in the transition.