Department of Biology and Biological Engineering, Systems and Synthetic Biology, Chalmers University of Technology, Kemivägen 10, 412 96, Gothenburg, Sweden.
Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Kemivägen 10, 412 96, Gothenburg, Sweden.
Microb Cell Fact. 2019 Mar 11;18(1):49. doi: 10.1186/s12934-019-1098-9.
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. 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.
We 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).
Changing 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.
长链脂肪酸（LCFAs），即碳链长度超过 18 个碳原子的脂肪酸（>C18），是从这些脂肪酸衍生出的特种化合物生产的研究热点。这些化合物包括游离脂肪酸，如芥酸（C22:1-Δ13），伯脂肪酸醇（FOHs），如二十二烷醇（C22:0-FOH），以及与霍霍巴油相似的蜡酯（WEs）（C38-WE 至 C44-WE），它们是（非常）长链脂肪酸和（非常）长链 FOH 的酯。特别是，FA、FOH 和 WE 用于生产化学品、药品和化妆品。霍霍巴籽油富含二不饱和 WE，其中超过 70%的成分由 C18:1-C24:1 单不饱和 FOH 和单不饱和 FA 组成。在这项研究中，我们旨在通过增加非常长链的单不饱和 FAs 的量并同时表达合成 WE 所需的酶，在酵母酿酒酵母中生产类似霍霍巴的 WE。
我们表明，植物衍生的脂肪酸延长酶（FAE/KCS）来自非洲油芥（CaKCS）与酵母固有脂肪酸去饱和酶（FAD）Ole1p 的联合表达导致 S. cerevisiae 中 C20:1 和 C22:1 FAs 的增加。我们还证明，用于 S. cerevisiae 中 C24:1 FA 生产的最佳酶候选物是来自海栖费氏弧菌（Marinobacter aquaeolei VT8）的 FAE（LaKCS）。CaKCS 和 Ole1p 的联合过表达，再加上来自中华相思树（Simmondsia chinensis）的脂肪酰基还原酶（FAR/FAldhR）和来自沙氏乳杆菌（Marinobacter aquaeolei VT8）的蜡合酶（WS）（MaFAldhR），在过量表达参与 FA 合成和延长的一系列其他酶的酿酒酵母菌株中，可产生大量单不饱和 FOH（最高可达 C22:1-FOH）和二不饱和 WE（最高可达 C46:2-WE）。
通过组合过表达来自各种来源的内源性和异源酶（例如，海洋桡足类或植物），可以改变酵母酿酒酵母的 FA 谱，使其向非常长链单不饱和 FA 转变。该策略用于在酿酒酵母中生产类似霍霍巴的 WE，并可潜在扩展到其他源自非常长链 FAs 的商业上有价值的产品。
