Increasing jojoba-like wax ester production in Saccharomyces cerevisiae by enhancing very long-chain, monounsaturated fatty acid synthesis

Leonie Wenning,Jens Nielsen,Christer S. Ejsing,Verena Siewers,Florian David,Richard R. Sprenger

doi:10.1186/s12934-019-1098-9

Abstract

BackgroundFatty acids (FAs) with a chain length of more than 18 carbon atoms (> C18) are interesting for the production of specialty compounds derived from these FAs. These compounds include free FAs, like erucic acid (C22:1-Δ13), primary fatty alcohols (FOHs), like docosanol (C22:0-FOH), as well as jojoba-like wax esters (WEs) (C38-WE to C44-WE), which are esters of (very) long-chain FAs and (very) long-chain FOHs. In particular, FAs, FOHs and WEs are used in the production of chemicals, pharmaceuticals and cosmetic products. Jojoba seed oil is highly enriched in diunsaturated WEs with over 70 mol% being composed of C18:1–C24:1 monounsaturated FOH and monounsaturated FA moieties. In this study, we aim for the production of jojoba-like WEs in the yeast Saccharomyces cerevisiae by increasing the amount of very long-chain, monounsaturated FAs and simultaneously expressing enzymes required for WE synthesis.ResultsWe show that the combined expression of a plant-derived fatty acid elongase (FAE/KCS) from Crambe abyssinica (CaKCS) together with the yeast intrinsic fatty acid desaturase (FAD) Ole1p leads to an increase in C20:1 and C22:1 FAs in S. cerevisiae. We also demonstrate that the best enzyme candidate for C24:1 FA production in S. cerevisiae is a FAE derived from Lunaria annua (LaKCS). The combined overexpression of CaKCS and Ole1p together with a fatty acyl reductase (FAR/FAldhR) from Marinobacter aquaeolei VT8 (MaFAldhR) and a wax synthase (WS) from Simmondsia chinensis (SciWS) in a S. cerevisiae strain, overexpressing a range of other enzymes involved in FA synthesis and elongation, leads to a yeast strain capable of producing high amounts of monounsaturated FOHs (up to C22:1-FOH) as well as diunsaturated WEs (up to C46:2-WE).ConclusionsChanging the FA profile of the yeast S. cerevisiae towards very long-chain monounsaturated FAs is possible by combined overexpression of endogenous and heterologous enzymes derived from various sources (e.g. a marine copepod or plants). This strategy was used to produce jojoba-like WEs in S. cerevisiae and can potentially be extended towards other commercially interesting products derived from very long-chain FAs.

Highlights

Fatty acids (FAs) with a chain length of more than 18 carbon atoms (> C18) are interesting for the production of specialty compounds derived from these fatty acid (FA)
Increasing the amount of monounsaturated fatty acid (MUFA) by expression of a heterologous ketoacyl-coenzyme A (CoA) synthases (KCSs) together with Ole1p of S. cerevisiae Previously, we demonstrated that jojoba-like wax ester (WE) can be synthesized in metabolically engineered S. cerevisiae strains by combined overexpression of the yeast intrinsic Elo2p together with a fatty acyl reductase (FAR) from M. aquaeolei and a wax synthase (WS) from S. chinensis, but the products were restricted to saturated very long-chain WEs (C40:0-WE and C42:0WE) [21]
We investigated the effect of overexpressing the endogenous Ole1p either together with the yeast intrinsic Elo2p or together with a heterologous plantderived fatty acid elongases (FAEs)/KCS enzyme in S. cerevisiae

Summary

Introduction

Fatty acids (FAs) with a chain length of more than 18 carbon atoms (> C18) are interesting for the production of specialty compounds derived from these FAs. We aim for the production of jojoba-like WEs in the yeast Saccharomyces cerevisiae by increasing the amount of very long-chain, monounsaturated FAs and simultaneously expressing enzymes required for WE synthesis. Fatty acids (FAs) play a major role during growth and maintenance of all living cells, since they are components of cell membrane lipids, organelle membrane lipids as well as storage lipids. They can function as signaling compounds in the form of sphingolipids. The FAs naturally found in the yeast Saccharomyces cerevisiae comprise mostly C16 and C18 species. MATa MAL2-8c SUC2 ura elo3Δ X-2::pMPC3::ACC1** X-3::IFA38::PHS1::TSC13::ACB1.

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