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.

Pathway Compartmentalization in Peroxisome of Saccharomyces cerevisiae to Produce Versatile Medium Chain Fatty Alcohols

“…We identified two parameters (C/N ratio and K + ions) that could potentially affect the fatty alcohol production based on previous reports2829. In general, it has been found that the production of fatty acid and the derived chemicals could be enhanced30 at high C/N ratio (i.e., nitrogen limited).…”

Recent advances in biosynthesis of fatty acids derived products in Saccharomyces cerevisiae via enhanced supply of precursor metabolites

“…A recent report found that overexpression of ACB1 could enhance the supply of fatty acyl-CoAs and increase the production of FAEEs by around 1.2-fold [58]. On the contrary, another study found that the deletion of ACB1 could enhance the cytosolic acyl-CoAs and increase the production of FAEEs by 1.48-fold [70].…”

“…Further engineering of the fatty acyl-CoAs supply by overexpression of ACB1 and NADPH supply by overexpression of GAPN (an NADP + -dependent glyceraldehyde-3-phosphate dehydrogenase) resulted in a final FAEEs titer of 48 mg/L [58], which represented the highest titer for FAEEs produced in S. cerevisiae from glucose (Table 1). Other efforts to increase the production of FAEEs include the overexpression of ACC1-FAS1-FAS2 [53], engineering of the post-translational regulation of ACC1 [56], the deletion of competing pathways [72], and the optimization of fermentation medium [70], but with only limited success ( Table 1). Besides glucose fermentation, S. cerevisiae was also engineered to produce FAEEs from other carbon sources such as glycerol.…”

Metabolic Engineering for Advanced Biofuels Production and Recent Advances Toward Commercialization

“…[83] However, titers of fatty acid alkyl esters reported in S. cerevisiae were relatively lower than titers in E. coli. [77,84] 4.3. Alkanes, Alkenes, and Methyl Ketones…”