Dynamic and Modular Control of Microbial Chemical and Protein Production Using Optogenetics

Abstract

Metabolic engineering aims to maximize production of valuable compounds using cells as biological catalysts. When incorporating engineered pathways into host organisms, an inherent conflict is presented between maintenance of cellular health and generation of products. This challenge has been addressed through various modalities of dynamic control: decoupling growth from production via two-phase fermentations and autoregulation of pathways to optimize product formation. Optogenetics offers even greater potential for metabolic engineering through user-mediated open-loop control. Here, we explore and develop modular optogenetic tools for the model organisms Escherichia coli and Saccharomyces cerevisiae. In Chapter 2, we develop optogenetic control of the E. coli lac operon, enabling the use of light to replace the prominently used inducer isopropyl β-D-1-thiogalactopyranoside (IPTG) for chemical and recombinant protein production. In Chapter 3, we import a heterologous activator-repressor protein pair into S. cerevisiae to develop simultaneously usable signal amplifiers and inverters. Finally, in Chapter 4, we demonstrate the use of optogenetics to manipulate the population dynamics of multi-species co-cultures. These studies validate optogenetics as a promising control modality for metabolic engineering, protein production, and other biotechnological applications.