Microalgae for Sustainable Carbon Capture: A Global Bibliometric Analysis of Research Progress

The persistent rise in atmospheric CO ₂ continues to intensify global climate change, prompting an urgent global push toward a sustainable carbon mitigation strategy. Among innovative approaches, microalgae-based carbon sequestration has emerged as a high-potential solution, owing to its rapid CO ₂ fixation rates (up to 1.8 kg CO ₂ per kg dry biomass), high biomass productivity, and applicability in industrial waste gas capture. This study offers a comprehensive global bibliometric analysis of research trends in microalgal carbon sequestration, based on 2,053 peer-reviewed publications from the Web of Science database between 1990 and 2025. Using advanced analytical tools, Biblioshiny (RStudio) and VOSviewer v1.6.20, the study investigates coauthorship networks, citation performance, keyword co-occurrence and thematic evolution, and leading articles related to the development of this domain. The findings reveal a steady increase in publication output, with China emerging as the leading contributor to research output, followed by India and the USA. Notable research hotspots include photobioreactor optimization, genetic modification of algal strains, biomass valorization, and integration with wastewater treatment systems. The analysis also underscores growing alignment with Sustainable Development Goals (SDGs), particularly SDG 6 and SDG 13. Despite progress, the sector continues to face economic and scalability barriers. High cultivation costs, energy-intensive harvesting, and limited industrial-scale deployments restrict commercial viability. This study emphasizes the need to cut costs via strain engineering, system integration, and policy support, along with cross-disciplinary efforts to move microalgae-based CO ₂ capture toward real-world applications.