Recent Advances in Cellular Synthesis of Structured Triacylglycerols

Triacylglycerols (TAGs) are essential energy reservoirs and industrial raw materials, while structured TAGs (STAGs) with tailored fatty acid distributions possess unique nutritional and functional values but low natural abundance. Enzymatic synthesis is strictly limited by feedstock and cost, making microbial de novo synthesis via metabolic engineering a promising alternative. This review summarizes advances in the fatty acid biosynthesis pathway and its regulation, key enzymes in TAG synthesis (GPAT, LPAAT, and DGAT), and microbial production of major STAGs (OPO, MLM, CBEs, and PUFA-rich STAGs). Current challenges and future perspectives are also discussed, promoting the shift toward rational design of functional STAGs.