From CO₂ emissions to valorization into high-value biochemicals: Advances, bottlenecks and market trajectories of biotechnologies

The valorization of carbon dioxide (CO₂)-rich streams is emerging as a key pillar of a circular, climate-neutral bioeconomy. Biological platforms such as microalgae cultivation, anaerobic fermentation and microbial polymer synthesis can convert CO₂ into high-value products. This review provides an updated synthesis of the state of the art, encompassing bibliometric trends, operational conditions, current technological readiness level (TRL), limitations in technology development, and market perspectives. Using a targeted scientometric analysis of Scopus entries and a critical appraisal of the experimental literature, this manuscript assesses the maturity of each conversion route, identifies the main technical bottlenecks, and highlights pathways for scale-up. From this bibliometric mapping on the valorization of CO2 and the evaluation of the current situation of the CO2 sector, the most relevant bio-products derived from CO2 were identified as alternative proteins from biomass, volatile fatty acids (VFAs), and biodegradable polyhydroxyalkanoates (PHAs). The level of maturity of the technologies of each group of processes, their future trends, and their bottlenecks are discussed in this manuscript.