Visiting Assistant Professor of Chemistry Andrew Jones recently published research results in mBio, one of the top journals of the American Society of Microbiology. The research was completed in the fall of 2016 and the paper, “Complete Biosynthesis of Anthocyanins Using E. coli Polycultures,” includes Catherine McCutcheon ’18 as a co-author.
The goal of the research was to engineer E. coli to synthesize an anthocyanin natural product found in strawberries. The vibrant red color and antioxidant properties of this class of molecules make it a prime candidate for use as natural food colorants.
Due to the large size of the biosynthesis pathway the researchers were unable to produce anthocyanin from glucose in a single strain. But by splitting the pathway across a synthetic community of four engineered E. coli strains, they were able to show proof-of-principle production of ~10mg/L anthocyanins.
To develop a functional pathway, they incorporated DNA from two species of bacteria, one yeast species and six species of plants into their wild type E. coli strain.
Jones said the paper is a starting point from which he and his fellow researchers can continue to improve titers to industrially relevant levels.
He said this work is the first example of a 4-strain synthetic microbial community. “By pushing the limits on the size of functional communities we can construct in the lab, we can begin to rival the complexity of natural communities found almost everywhere on, in, and around our bodies,” Jones added.
“There is still a lot to be learned about natural communities and we hope that through the continued study of both natural and synthetic systems we will be able to learn more about how to manipulate and modify microbial communities to our benefit.”
In the process of building the anthocyanin pathway, the researchers also developed several phenylpropanoic acid production strains capable of gram per liter titers.
Jones said this is significant because it represents the highest production titers to date for both p-coumaric and caffeic acids. “Phenylpropanoic acids are an important substrate in the synthesis of anthocyanins, but also have their own interesting anti-oxidant, anti-cancer and anti-fungal properties,” he noted.