Verification and applications of 1-deoxynojirimycin biosynthesis: Recent advances and future prospects

1-deoxynojirimycin (DNJ), a piperidine iminosugar analogous to D-glucose, exhibits various biological properties with antidiabetic, antiviral, anti-inflammatory, and antimicrobial effects. N-alkylated DNJ derivatives have been used clinically as medicines for type 2 diabetes and lysosomal storage diseases. DNJ naturally occurs in plants and microbes, and the methods of DNJ production in these organisms have attained stereoselectivity with more environmentally friendly and simpler processes than chemical synthesis. However, the yield of DNJ has to be improved by reinforcing its biosynthetic pathway. This review summarizes the various DNJ-producing species and the production titer of DNJ in plants and microbes. Additionally, it compares the methods used to validate the biosynthesis of DNJ in plants and in microbes. It also covers the application of some DNJ biosynthesis-related genes and the enhancement of DNJ content via metabolic engineering. Finally, this review highlights new biological sources of other iminosugars that can be detected through the knowledge of DNJ biosynthesis.