(670c) Synthetic Microbial Consortia for Overproducing Structurally Complex Isoprenoids

Constructing heterologous metabolic pathways in microbes has enabled the host cells to synthesize diverse natural metabolites of great importance to the modern world. To date, however, structurally complex molecules are still difficult to produce by this approach, simply because the corresponding biosynthetic pathways are quite long presenting often special challenges to the host cell; i.e. more genes need to be introduced to host cells and their expression levels need to be optimized for seamless functioning of the whole pathway. In this study, we demonstrate that a long pathway can be divided into two segments, which were separately reconstituted in two different types of cells that cooperated to complete the entire pathway; i.e. one cell produced a metabolic intermediate that diffuses to the other cell where it is further converted into the desired product. By doing so, the number of genes that need to be introduced into a single cell is significantly reduced, and each pathway segment in each cell can also be constructed and tuned in parallel, greatly speeding up the engineering process. In addition, special traits of different organisms (e.g. fast growth of bacteria, advanced protein expression machinery of yeasts etc.) can be leveraged. Here, we have developed a stable co-culture of Escherichia coli and Saccharomyces cerevisiae, and demonstrated that they can be used to efficiently synthesize a variety of structurally complex isoprenoids - a large family of useful natural products. The novel co-culture concept demonstrated in this study opens a new avenue for reconstituting long pathways in microbes for metabolite overproduction.