Research progress in the synthesis of 3′- and 6′-sialactose by Escherichia coli

Abstract:

Human milk oligosaccharides (HMOs) are a structurally complex group of unbound polysaccharides, representing the third-largest solid component in breast milk. They play a crucial role in the intestinal health and immune system development of infants. Sialylated HMOs, including 3′-sialactose (3′-SL) and 6′-sialactose (6′-SL), are major components of HMOs, playing significant roles in immune regulation, anti-inflammatory processes, and promotion of probiotic growth. Currently, the cost-effective production of high-value sialactose by microbial fermentation with readily available raw materials has become a research hotspot due to the high nutritional value and potential applications of sialylated HMOs in infant food. This paper summarizes the functions and biosynthesis of 3′-SL and 6′-SL. Furthermore, it reviews the research progress in the synthesis of sialactose by Escherichia coli, offering valuable insights for future industrial production.