Microbial Production of Natural and Unnatural Betalain Pigments
Betalain pigments are one of the most famous pigments in plant kingdom. They are comprised of red-purple colored betacyanins and yellow-orange colored betaxanthins. For their high antioxidant properties, sunlight absorbing ability, they have been isolated from plants and commercially utilized as food additives, cosmetic ingredients and dye-sensitized solar cells. However, the cost of current betalain pigments production process depending on extraction from plants is very high due to their extremely low content in plant. Therefore, development of other economically efficient industrial production process has been strongly expected. One of the solutions is considered to be microbial production process. In this study, we successfully engineered metabolic pathway of Escherichia coli and Saccharomyces cerevisiae to produce betalain pigments and confirmed that both betacyanins and betaxanthins were produced by these engineered microorganism in an appropriate culture condition. This is the first report of integrated microbial betalain pigments production from simple carbon source. This result may contribute to the development of cost efficient and sustainable industrial production process of betalain pigments.