ABSTRACT
The substitution of fossil fuels for renewable biomass feedstock is urgent, since fossil fuel sources are not only scarce, but their use is also environmentally unfriendly. In this context, the concept of circular bioeconomy arises, including both the use of renewable resources, as well as what could have been considered waste material (solid and liquid residues) in cycles, preventing wastage. This last option reduces environmental impacts and costs with treatments and enables the generation of added-value products, while also exceeding other options in sustainable and social aspects, thus the reason why it is called a circular bioeconomy. Since circular bioeconomy is of utmost importance, this chapter aims to contribute to its knowledge. For that, besides definitions and concepts, contributions of the bioeconomy to the circular economy and vice versa, the diversity of bioeconomies around the world, and the existing barriers, challenges, and opportunities will be presented.
