Wax esters (WEs) are neutral lipids of major industrial importance used as components of lubricants, pharmaceuticals, and cosmetics. Large-scale production of WEs is based on chemical processes, which utilize petroleum-derived feedstocks and generate hazardous waste. Comparably small amounts of natural WEs can be obtained from Simmondsia chinensis (jojoba), the only plant known to use WEs as major storage lipids. Despite recent advances in lipid biotechnology, platforms for efficient bio-based WE production are not yet available. Metabolic engineering of oilseeds for WE accumulation represents a promising strategy for renewable, sustainable, and environment-friendly production of lipids tailored to industrial applications
The formation of WEs from acyl-CoAs and fatty alcohols requires the activity of only two enzymes: a fatty acyl reductase (FAR) and a wax synthase (WS). Numerous studies demonstrated the establishment of the WE biosynthetic pathway in seeds of non-food plants, such as Arabidopsis thaliana, Camelina sativa, and Crambe abyssinica. However, seeds with high amounts of WEs showed reduced germination rates and defects during post-germinative growth, most probably due to poor WE catabolism and/or accumulation of potentially toxic fatty alcohols [1].
In the current approaches aimed at producing WEs in oilseeds, two pathways are the main focus: WE synthesis and mobilisation. The isolation and characterisation of FARs and WSs of various origins and different specificities opened the possibility of modifying the chemical structure of the WEs accumulated in the seeds. Meanwhile, studying WE mobilisation in jojoba seeds led to identification of three enzymatic activities required in this process: a lipase, a fatty alcohol oxidase (FAO), and a fatty aldehyde dehydrogenase (FADH) [2].
During the talk, I will focus on the strategies of WE production in seeds, including the investigation of the substrate specificity of the selected FARs and WSs [3], and on characterisation of WE-hydrolysing activity of lipases from jojoba [4], C. sativa, and C. abyssinica.
- Domergue, F., Miklaszewska, M., 2022. The production of wax esters in transgenic plants: towards a sustainable source of bio-lubricants. J Exp Bot 73, 2817–2834. https://doi.org/10.1093/jxb/erac046.
- Rajangam, A.S., Gidda, S.K., Craddock, C., Mullen, R.T., Dyer, J.M., Eastmond, P.J., 2013. Molecular characterization of the fatty alcohol oxidation pathway for wax-ester mobilization in germinated jojoba seeds. Plant Physiol 161, 72–80. https://doi.org/10.1104/pp.112.208264.
- Miklaszewska, M., Banaś, A., 2016. Biochemical characterization and substrate specificity of jojoba fatty acyl-CoA reductase and jojoba wax synthase. Plant Science 249, 84–92. https://doi.org/10.1016/j.plantsci.2016.05.009.
- Kawiński, A., Miklaszewska, M., Stelter, S., Głąb, B., Banaś, A., 2021. Lipases of germinating jojoba seeds efficiently hydrolyze triacylglycerols and wax esters and display wax ester-synthesizing activity. BMC Plant Biol 21, 50. https://doi.org/10.1186/s12870-020-02823-4.