Background:
Wax ester synthases (WS) can synthesize wax esters from alcohols and fatty acyl coenzyme A (acyl-CoA) thioesters. The knowledge of the preferred substrates for each WS allows the use of yeast cells for production of wax esters that are high-value materials and can be used in a variety of industrial applications. The products of WSs include fatty acid ethyl esters (FAEEs), which can be directly used as biodiesel.
Results:
Here, heterologous WSs derived from five different organisms were successfully expressed and evaluated for their substrate preference in Saccharomyces cerevisiae. We investigated the potential of the different WSs for biodiesel (i.e. FAEEs) production in S. cerevisiae. All investigated WSs, i.e. from Acinetobacter baylyi ADP1, Marinobacter hydrocarbonoclasticus DSM 8798, Rhodococcus opacus PD630, Mus musculus C57BL/6, and Psychrobacter arcticus 273-4, have different substrate specificities, but they can all lead to the formation of biodiesel. The best biodiesel producing strain was found to be the one expressing WS from M. hydrocarbonoclasticus DSM 8798 that resulted in a biodiesel titer of 6.3 mg/l. To further enhance biodiesel production, acetyl-CoA carboxylase was up-regulated, which resulted in a 30% increase in biodiesel production.
Conclusions:
Five wax ester synthases from different species were functionally expressed and their substrate preference characterized in S. cerevisiae thus constructing cell factories for production of specific kinds of wax ester. WS from M. hydrocarbonoclasticus showed the highest preference for ethanol compared to the other WSs, and could permit the engineered S. cerevisiae to produce biodiesel.Source:
http://www.biotechnologyforbiofuels.com/rss/