Microbial CO₂ bioconversion: integrating carbon fixation pathways and sustainable biomanufacturing

The continued rise in atmospheric carbon dioxide (CO₂) concentrations has intensified the need for sustainable technologies capable of mitigating greenhouse gas emissions while generating value-added products. In this context, microbial CO₂ bioconversion has emerged as a promising biological strategy within broader carbon capture, utilization, and storage (CCUS) frameworks, particularly through biological carbon capture and utilization (bio-CCU). These approaches enable the conversion of inorganic carbon into fuels, chemicals, biomaterials, proteins, and other value-added products. This review provides a comprehensive assessment of recent advances in microbial CO₂ bioconversion by bridging biological, technological, and industrial perspectives. Unlike previous reviews focusing on individual topics, such as carbon fixation pathways, gas fermentation, or metabolic engineering, this work presents an integrated framework connecting natural and synthetic carbon fixation pathways, microbial production platforms, metabolic engineering strategies, product diversification, and techno-economic considerations. To support this analysis, we conducted a systematic bibliometric assessment of 913 publications indexed in the Web of Science Core Collection, revealing sustained growth in scientific output, increasing interdisciplinarity, structured collaboration networks, and strong thematic interconnections across microbial ecology, carbon fixation, metabolism, and carbon utilization. Recent advances in synthetic biology, systems-level metabolic engineering, microbial electrosynthesis, bioelectrochemical systems, synthetic microbial consortia, and artificial intelligence-assisted strain engineering are discussed as important drivers of microbial carbon utilization. The review also critically examines major barriers to industrial implementation, including CO₂ mass transfer, carbon fixation efficiency, energy constraints, process scale-up, downstream processing, and economic feasibility. By integrating systematic bibliometric evidence with a critical assessment of microbial CO₂ biomanufacturing, this review identifies the convergence of microbial physiology, metabolic engineering, bioprocess development, renewable energy, and data-driven approaches as central to advancing biological CO₂ conversion toward scalable, sustainable biomanufacturing.