Improvement of betanin biosynthesis in Saccharomyces cerevisiae by metabolic engineering

Betanin is a member of natural pigment betacyanins family and has extensive application in the food industry as an important natural red food colorant. Its relatively inefficient production in nature however hampers access to this phytochemicals through traditional crop-based manufacturing. Microbial bioproduction therefore represents an attractive alternative. Here, we present the construction of a Saccharomyces cerevisiae strain for betanin production. Through minimizing metabolic crosstalk, screening and modifying biosynthetic enzymes, enhancing pathway flux and optimizing fermentation conditions, a final titer of betanin of 28.7 mg/L was achieved from glucose at 25 °C in baffled shake-flask, which is the highest reported titer produced by yeast to our knowledge. This work provides a promising step towards developing synthetic yeast cell factories for de novo biosynthesis of value-added betanin and other betacyanins.