Biosynthesis of functional carbohydrates from glycolytic node precursors glucose-6-phosphate and...

Glucose-6-phosphate (G-6-P) and fructose-6-phosphate (F-6-P), which are located upstream of glycolysis, are crucial node compounds that provide carbon skeletons and supply energy for cell growth. De novo microbial synthesis of functional carbohydrates involves the derivatization of G-6-P and F-6-P. It is often associated with negative growth effects, creating challenges for efficient production. In this review, the main derivatization reactions with G-6-P and F-6-P as precursors were divided into three categories: the IAD (Isomerization And Dephosphorylation) module, the FGF (F-6-P to GDP-Fucose) module, and the FAA (F-6-P transAcetylation and transAmination) module. The representative functional carbohydrates of these pathways were briefly introduced, and pathway reconstruction and optimization for these carbohydrates were summarized. In addition, advances in central carbon metabolism regulation for G-6-P and F-6-P redirection were classified and summarized. Finally, the synthesis of functional carbohydrates by microbial redirection of G-6-P and F-6-P was investigated. This review facilitates the understanding of strategies and core principles involved in glycolytic node G-6-P and F-6-P redirection and the de novo biosynthesis of functional carbohydrate derivatives. It has significant implications for constructing efficient microbial cell factories that redirect G-6-P and F-6-P to derivatives and enable their industrial production.