Affiliation:
1. Austrian Centre of Industrial Biotechnology (acib GmbH), Petersgasse 14, 8010 Graz, Austria
2. Institute of Molecular Biotechnology, Graz University of Technology, NAWI Graz, BioTechMed Graz, Petersgasse 14, 8010 Graz, Austria
Abstract
Fatty acids have been supplied for diverse non-food, industrial applications from plant oils and animal fats for many decades. Due to the massively increasing world population demanding a nutritious diet and the thrive to provide feedstocks for industrial production lines in a sustainable way, i.e., independent from food supply chains, alternative fatty acid sources have massively gained in importance. Carbohydrate-rich side-streams of agricultural production, e.g., molasses, lignocellulosic waste, glycerol from biodiesel production, and even CO2, are considered and employed as carbon sources for the fermentative accumulation of fatty acids in selected microbial hosts. While certain fatty acid species are readily accumulated in native microbial metabolic routes, other fatty acid species are scarce, and host strains need to be metabolically engineered for their high-level production. We report the metabolic engineering of Pichia pastoris to produce palmitoleic acid from glucose and discuss the beneficial and detrimental engineering steps in detail. Fatty acid secretion was achieved through the deletion of fatty acyl-CoA synthetases and overexpression of the truncated E. coli thioesterase ‘TesA. The best strains secreted >1 g/L free fatty acids into the culture medium. Additionally, the introduction of C16-specific ∆9-desaturases and fatty acid synthases, coupled with improved cultivation conditions, increased the palmitoleic acid content from 5.5% to 22%.
Funder
Austrian Research Promotion Agency FFG
Ministry of Climate Protection
Styrian Business Promotion Agency, SFG
TU Graz Open Access Publishing Fund
Reference107 articles.
1. A Brief Journey into the History of and Future Sources and Uses of Fatty Acids;Cerone;Front. Nutr.,2021
2. Dartiailh, C., Cicek, N., Sorensen, J.L., and Levin, D.B. (2020). The Handbook of Polyhydroxyalkanoates, CRC Press.
3. De Carvalho, C.C.C.R., and Caramujo, M.J. (2018). The Various Roles of Fatty Acids. Molecules, 23.
4. Storage Lipids of Yeasts: A Survey of Nonpolar Lipid Metabolism in Saccharomyces cerevisiae, Pichia pastoris, and Yarrowia lipolytica;Koch;FEMS Microbiol. Rev.,2014
5. Revisiting Metabolic Engineering Strategies for Microbial Synthesis of Oleochemicals;Yan;Metab. Eng.,2020