Enhancing fatty acid ethyl ester production in Saccharomyces cerevisiae through metabolic engineering and medium optimization

Abstract

Biodiesels in the form of fatty acyl ethyl esters (FAEEs) are a promising next generation biofuel due to their chemical properties and compatibility with existing infrastructure. It has recently been shown that expression of a bacterial acyl-transferase in the established industrial workhorse Saccharomyces cerevisiae can lead to production of FAEEs by condensation of fatty acyl-CoAs and ethanol. In contrast to recent strategies to produce FAEEs in S. cerevisiae through manipulation of de novo fatty acid biosynthesis or a series of arduous genetic manipulations, we introduced a novel genetic background, which is comparable in titer to previous reports with a fraction of the genetic disruption by aiming at increasing the fatty acyl-CoA pools. In addition, we combined metabolic engineering with modification of culture conditions to produce a maximum titer of over 25 mg/L FAEEs, a 40% improvement over previous reports and a 17-fold improvement over our initial characterizations. Biotechnol. Bioeng. 2014;111: 2200-2208. © 2014 Wiley Periodicals, Inc.

Keywords: Saccharomyces cerevisiae; biodiesel; fatty acid ethyl ester; metabolic engineering; nitrogen limitation.