Biomanufacturing, an important and novel development model aimed at solving climate, energy, and food crises, has the advantages of raw material sustainability, environmental friendliness, and product safety, compared with traditional petrochemical production methods (Keasling, 2010; Sun et al., 2023a). De novo microbial biosynthesis is a type of biomanufacturing method in which cheap substrates are metabolized by microbial cells to synthesize high value–added compounds (Makaranga et al., 2024; Pierrel et al., 2022; Pressley et al., 2024). In contrast to traditional chemical catalysis methods, this method relies on organisms to obtain the target compound through intracellular, multistep, enzyme-catalyzed reactions and does not rely on metal catalysts and chemical reagents. Glucose is the simplest and most commonly used carbon source for microbial fermentation and an inexpensive substrate for de novo biosynthesis. Glucose-6-phosphate (G-6-P) and fructose-6-phosphate (F-6-P) serve as precursors after glucose enters the microbial glycolysis pathway. These molecules proceed through glycolysis into the tricarboxylic acid cycle (TCA) and enter the pentose phosphate pathway (PPP), where they generate NADPH for bioreactions and energy production. Additionally, they provide carbon skeletons essential for nucleotide biosynthesis (Richhardt et al., 2013; Xu et al., 2020). The production of functional carbohydrates through de novo microbial synthesis is an additional consumption process in addition to normal physiological processes in microorganisms. The improvement in biosynthesis ability is accompanied by a decrease in growth ability. The biosynthesis of target functional carbohydrates with G-6-P and F-6-P as precursors involves their derivatization. The biosynthesis efficiency is mainly determined by the distribution of carbon flow between the derivatization pathway and the glycolytic node, i.e., the carbon flow redirection efficiency. Strategies to improve this efficiency mainly include synthetic pathway optimization and metabolic flow regulation during the normal growth of microorganisms (Lin and Tao, 2017). The de novo synthesis of G-6-P- and F-6-P-derived functional carbohydrates mainly involves the construction and optimization of derivatization modules as well as the regulation of central carbon metabolism (Taylor et al., 2023; You et al., 2020).

In this review, the primary derivatization reactions for redirecting G-6-P and F-6-P to carbohydrate biosynthesis are divided into three modules: IAD (Isomerization And Dephosphorylation), FGF (F-6-P to GDP-Fucose), and FAA (F-6-P transAcetylation and transAmination) (Fig. 1). Pathway optimizations for functional carbohydrate biosynthesis involving these three representative derivatization modules are summarized. They include myo-inositol and D-allulose production for the IAD module, fucosyllactose production for the FGF module, and GlcNAc production for the FAA module. Furthermore, the strategies for achieving efficient production of high-value carbohydrates via the redirection of glycolysis node compounds for microbial de novo synthesis are analyzed in detail from two perspectives: dynamic regulation of the switching of growth to production and static downregulation of the G-6-P and F-6-P degradation pathway. Finally, the prospects for integrating metabolic engineering and synthetic biology techniques to promote the derivative-based production of glycolysis node compounds are discussed.