Dynamic two-phase fermentation in S. cerevisiae allows for rapid and scalable strain design for microbial chemical synthesis.

Microbes designed in the laboratory often function much differently in lab scale evaluations as compared to  large-scale industrial fermenters. As a result designers microbe often haver to be uniquely optimized for each product andeach strain then scaled up independently, which can be a costly and time consuming process. To overcome these limitations we have developed a scalable, two-stage bioprocess in S. cerevisiae, which decouples growth from product synthesis. Yeast are grown to a target biomass in a limiting nutrient, where depletion of the limiting nutrient inducibly turns off essential genes and redirects carbon, electron, and energy flux towards the desired product. Dynamic control is enabled through combinatorial use of inducible promoters, CRISPRi, and regulated protein degradation. We demonstrate that this strain design is capable of production of several different industrially relevant metabolites, all of which are scalable from micro-liter to liter scale.