(567j) Strategies for Improved Anthocyanin Biosynthesis in Recombinant E. Coli

Polyphenols in general and anthocyanins in particular have recently drawn vast interest due to their associated health benefits. Recent studies suggest that anthocyanins could have a preventative effect on diabetes, obesity, cancer, and cardiovascular disease. However, significant research into these health benefits is limited by the difficulty and high cost of obtaining pure compounds or well-defined mixtures from plants. An attractive alternative is production in recombinant microorganisms such as Escherichia coli. As a production platform, E. coli has been extensively engineered for various non-native products. In addition, the growth characteristics of E. coli allows for efficient production of non-natural analogues. In this talk, we demonstrate strategies to optimize anthocyanin biosynthesis in recombinant E. coli. One strategy involved directing carbon-flow towards the biosynthesis reactions based on predictions from the recent OptForce model. Based on flux measurements available for the wild-type strain of E. coli (BL21Star), OptForce identified the fluxes that must be modified in order to ensure that the metabolic network produces anthocyanin at the target yield. The predicted interventions guaranteed a yield of 75% of theoretical maximum yield for anthocyanin while supporting the production of biomass. Another strategy was designed to improve transport of anthocyanins to the culture media after synthesis to simplify product recovery after fermentation. Here, the expression of the bacterial transport proteins was manipulated to increase anthocyanin titers in culture media. Finally, we took a closer look at improving expression levels of anthocyanin biosynthesis genes through translational studies.