Break

Bacterial membranes are composed of proteins embedded in a lipid matrix. Bacteria are able to survive in a range of environments due to their ability to maintain membrane stability, which is achieved by adjusting the abundance of various proteins and phospholipids in order to fine-tune the biophysical properties of the cell membrane. Membrane lipid composition is modulated by modifying pre-existing phospholipids and by manufacturing different types of fatty acids. The use of microbial processes to produce biorenewable chemicals and biofuels has been growing, providing a sustainable alternative to fossil-fuel based products. However, most industrially useful chemicals are inhibitory to bacteria, which limits the efficiency and productivity of these bioprocesses. One strategy to improve microbial productivity is engineering bacteria to tolerate higher concentrations of toxic chemicals in order to produce strains with both an improved tolerance to the inhibitors and the capacity to produce desired metabolites at higher rates. The goal of my project is to explore the relationship between various protein sequence variations and microbial characteristics. This was accomplished by testing the tolerance of several genetically modified strains of E. coli to a variety of desirable compounds and chemical precursors. Cells were grown in minimal media in the presence of the inhibitors and optical density was periodically measured to assess growth. We found that knocking out or overexpressing certain genes had different effects depending on the microbial strain and inhibitor tested, and certain genetic variations more than others tended to improve or decrease an engineered strain’s growth in specific inhibitors. Ultimately, this will help advance the long-term goal of engineering microbes with multiple genetic variations to optimize their resilience and utility in bioenergy applications.