Optogenetic regulation of branched-chain higher alcohol biosynthesis to control advanced biofuel blends

Abstract

With increasing greenhouse gas (GHG) emissions, the use of petroleum must be curtailed to avoid drastic climate effects. The transportation sector currently accounts for 29% of GHG emissions in the United States and still relies largely on petroleum-based fuels. * Biofuels, specifically branched-chain higher alcohols (BCHAs) such as isobutanol (IbOH), isopentanol (IpOH), and 2-methyl-1-butanol (2-MBOH) are attractive alternatives. BCHAs are energy dense and do not have the levels of volatility and hygroscopicity as their less energy dense counterpart, ethanol. The yeast Saccharomyces cerevisiae, which naturally produces BCHAs in trace amounts can be metabolically engineered to produce these compounds at higher quantities. This project’s aim is to develop genetically modified yeast strains that have light inducible control of the BCHA pathways. This will allow for easier manipulation of the pathways’ titer levels and a more efficient way to obtain the fuel with one strain in comparison to using two separate strains simultaneously.