(152a) Genome-Scale Engineering for the Construction and Optimization of Yeast Cell Factories

Biological conversion of renewable feedstock into fuels and chemicals has been intensively investigated due to increasing concerns on sustainability and global climate change. Compared with its counterparts, Saccharomyces cerevisiae, the bakerâ??s yeast, is more industrially relevant thanks to its well-studied genetic and physiological background, the availability of a large collection of genetic tools, the compatibility of high-density and large-scale fermentation, the resistance to phage infection, and the high tolerance against toxic inhibitors and products. Therefore, we aim to develop platform yeast cell factories for efficient and cost-effective production of biofuels and chemicals. To achieve this, the host genome should be engineered such as the disruption of the competing pathways to redirect the metabolic fluxes to biosynthesis of the desired products. Although a wide variety of cell factories have been constructed, we are still facing the challenges of constructing efficient cell factories in a short period of time. Therefore, we took advantage of the recently developed CRISPR/Cas9 system to facilitate the development of cell factories. The CRISPR/Cas9 system was adopted to achieve both gain of function (knock-in and gene activation) and loss of function (knock out and gene repression) in yeast. More importantly, we combined gene deletion, gene repression, and gene activation into a single system. By doing this, we could engineer any gene of interest with a full spectrum of gene expression profiles (zero expression, down-regulation, and up-regulation). Finally, genome-scale studies were performed to develop a rapid and efficient strategy for the construction of cell factories and unveil the synergistic effects between gene deletion, gene repression, and gene activation in yeast.

Keywords: Yeast cell factory; Genome engineering; CRISPR/Cas9; Gain-of-function; Loss-of-function