Sustainable biomanufacturing of fat-soluble vitamins: Rewiring carbon flux and green carbon management

Fat-soluble vitamins (vitamins A, D, E, and K) are essential, high-value micronutrients with surging global demand. Traditionally, their industrial production has relied heavily on fossil-derived chemical synthesis or resource-intensive plant extraction, both of which are constrained by high carbon footprints, low atom economy, and severe environmental pollution. In contrast, microbial biomanufacturing offers a transformative "Green Carbon" strategy by valorizing renewable carbon sources into these complex functional compounds. This review systematically summarizes recent advancements in the green biosynthesis of fat-soluble vitamins. We focus on how synthetic biology and metabolic engineering are utilized to rewire carbon flux toward farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP), which act as the central carbon nodes for all fat-soluble vitamins. Furthermore, we categorize specific engineering approaches, such as modular pathway optimization, directed enzyme evolution, and global metabolic network balancing, implemented across typical industrial chassis ( Escherichia coli , Bacillus subtilis , Saccharomyces cerevisiae , and Yarrowia lipolytica ) to maximize carbon conversion efficiency. The review details the green process routes, fermentation scales, and yield breakthroughs achieved to date. Finally, we discuss future technical strategies aligned with carbon neutrality goals, emphasizing the potential of next-generation green carbon sources to provide a theoretical roadmap for low-carbon and highly efficient microbial manufacturing in the global health industry.