Biosynthesis of L-fucose and L-fuculose using engineered Saccharomyces cerevisiae

Recently, L-fucose has received considerable attention as a potential cosmetic agent and substrate for human oligosaccharide synthesis. To date, only two methods have been reported for L-fucose biosynthesis: microbial biosynthesis based on the GDP-L-fucose pathway and enzymatic conversion using the L-fucose metabolic pathway enzymes. The lack of efficient biosynthetic methods has increased the price of L-fucose and other valuable chemicals synthesized from L-fucose. In this study, we introduced the L-fucose metabolic pathway from Escherichia coli into Saccharomyces cerevisiae and reverse-synthesized 7.75 mg/L L-fucose and 1.55 mg/L L-fuculose with lactaldehyde and glucose as substrates. L-fuculose was synthesized as a by-product of L-fucose biosynthesis. Conversion of lactaldehyde to 1,2 propanediol by an unknown oxidoreductase from S. cerevisiae is the bottleneck for fucose synthesis. To the best of our knowledge, this study is the first to reverse synthesize L-fucose and L-fuculose using whole cells via L-fucose metabolism.