Metabolic Engineering of an Oleaginous Yeast for the Production of Omega-3 Fatty Acids

Zhu, Quinn; Xue, Zhixiong; Yadav, Naren; Damude, Howard G.; Pollak, Dana Walters; Rupert, Ross; Seip, John E.; Hollerbach, Dieter; Macool, Daniel; Zhang, Hongxiang; Bledsoe, Sidney A; Short, David R.; Tyréus, Björn D.; Kinney, Anthony J.; Picataggio, Stephen

doi:10.1016/b978-1-893997-73-8.50007-4

Cited by 16 publications

(22 citation statements)

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“…The overall strategy being to genetically modify existing organisms that have oil deposition as a major trait and thus combine this with the n-3 LC-PUFA biosynthesis trait. Potential candidates include other oleaginous microorganisms or conventional oilseed crops to produce entirely novel sources of de novo n-3 LC-PUFA (Zhu et al, 2010;Sayanova and Napier, 2011).…”

Section: Transgenicsmentioning

confidence: 99%

Omega-3 long-chain polyunsaturated fatty acids and aquaculture in perspective

2015

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Abbreviations: ARA, arachidonic acid (20:4n-6); CVD, cardiovascular disease; DHA, docosahexaenoic acid (22:6n-3); DPA, docosapentaenoic acid (22:5n-3); EFA, essential fatty acid; Elovl, fatty acid elongase; EPA, eicosapentaenoic acid (20:5n-3); Fads, fatty acyl desaturase; FM, fishmeal; FO, fish oil; LC-PUFA, long-chain polyunsaturated fatty acids (≥ C20 ≥ 3 double bonds); LOA, linoleic acid (18:2n-6); LNA, linolenic acid (18:3n-3); PUFA, polyunsaturated fatty acid; TAG, triacylglycerol; VO, vegetable oil. ABSTRACTIn the 40 years since the essentiality of polyunsaturated fatty acids (PUFA) in fish was first established by determining quantitative requirements for 18:3n-3 and 18:2n-6 in rainbow trout, essential fatty acid (EFA) research has gone through distinct phases. For 20 years the focus was primarily on determining qualitative and quantitative EFA requirements of fish species. Nutritional and biochemical studies showed major differences between fish species based on whether C 18 PUFA or long-chain (LC)-PUFA were required to satisfy requirements. In contrast, in the last 20 years, research emphasis shifted to determining "optimal" levels of EFA to support growth of fish fed diets with increased lipid content and where growth expectations were much higher. This required greater knowledge of the roles and functions of EFA in metabolism and physiology, and how these impacted on fish health and disease. Requirement studies were more focused on early life stages, in particular larval marine fish, defining not only levels, but also balances between different EFA. Finally, a major driver in the last 10-15 years has been the unavoidable replacement of fish oil and fishmeal in feeds and the impacts that this can have on n-3 LC-PUFA contents of diets and farmed fish, and the human consumer. Thus, dietary n-3 in fish feeds can be defined by three levels.Firstly, the minimum level required to satisfy EFA requirements and thus prevent nutritional pathologies. This level is relatively small and easy to supply even with today's current high demand for fish oil. The second level is that required to sustain maximum growth and optimum health in fish being fed modern high-energy diets. The balance between different PUFA and LC-PUFA is important and defining them is more challenging, and so ideal levels and balances are still not well understood, particularly in relation to fish health. The third level is currently driving much research; how can we supply sufficient n-3 LC-PUFA to maintain the nutritional quality of farmed fish at the same level as 20 years ago, and similar or better than in wild fish? This level far exceeds the biological requirements of the fish itself and to satisfy it we require entirely new sources of n-3 LC-PUFA. We cannot rely on the finite and limited marine resources that we can sustainably harvest or 3 efficiently recycle. We need to produce n-3 LC-PUFA de novo and all possible options should be considered.Keywords: Fish oil; essential fatty acids; nutrition; health; metabolism; sustainability 4 Highl...

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Section: Transgenicsmentioning

confidence: 99%

Omega-3 long-chain polyunsaturated fatty acids and aquaculture in perspective

2015

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“…De-pending on the product of interest, other hosts may be more suitable. In the case of omega-3 fatty acid production, Y. lipolytica has proven to be an excellent host due to its friendly genetic system, easy fermentation scale-up, and ability to accumulate oil [14]. As for plant hosts, the competition of native enzymes for pathway intermediates could reduce the carbon flux and lead to formation of unintended products [64,65].…”

Section: Resultsmentioning

confidence: 99%

“…LA and ALA can be converted to EPA and DHA by adding more carbon atoms and unsaturated bonds. These reactions are catalyzed by a series of elongases and desaturases [12][13][14]. There are two possible pathways to synthesize EPA from LA and ALA.…”

Section: Biosynthetic Pathways Of Omega-3 Fatty Acidsmentioning

confidence: 99%

“…Integration events are predominantly random, and favorable integration events can be selected [24]. The general strategy of pathway engineering in this organism is to clone genes related to omega-3 biosynthesis with appropriate promoters and terminators and express these genes in the chromosome [14].Three methods are used to increase gene expression: (i) selection of promoters with appropriate strength; (ii) optimization of codon usage for each foreign gene; and (iii) integration of multiple copies of genes in the chromosome.To identify promoters with appropriate strength, the E. coli β-glucuronidase reporter system is used. A suite of promoters, including GPM, GPD, and FBA are useful for gene expression.…”

Section: Bioengineering Of Yarrowia Lipolytica For Omega-3 Fatty Acidmentioning

confidence: 99%

“…Starting with Δ6-desaturase, both LA and ALA can be converted to EPA with a combination of C 18/20 -elongase, Δ5-desaturase, and/or Δ17-desaturase. Multiple copies of genes encoding these elongases and desaturases were inserted into the Y. lipolytica chromosome [14]. In addition, two copies of C 16/18 -elongase and 3 copies of Δ12-desaturase were added to increase the flux from palmitic acid.…”

Section: Bioengineering Of Yarrowia Lipolytica For Omega-3 Fatty Acidmentioning

confidence: 99%

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Metabolic engineering for the production of clinically important molecules: Omega‐3 fatty acids, artemisinin, and taxol

Bhatia

2011

Biotechnology Journal

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Driven by requirements for sustainability as well as affordability and efficiency, metabolic engineering of plants and microorganisms is increasingly being pursued to produce compounds for clinical applications. This review discusses three such examples of the clinical relevance of metabolic engineering: the production of omega-3 fatty acids for the prevention of cardiovascular disease; the biosynthesis of artemisinic acid, an anti-malarial drug precursor, for the treatment of malaria; and the production of the complex natural molecule taxol, an anti-cancer agent. In terms of omega-3 fatty acids, bioengineering of fatty acid metabolism by expressing desaturases and elongases, both in soybeans and oleaginous yeast, has resulted in commercial-scale production of these beneficial molecules. Equal success has been achieved with the biosynthesis of artemisinic acid at low cost for developing countries. This is accomplished through channeling the flux of the isoprenoid pathway to the specific genes involved in artemisinin biosynthesis. Efficient coupling of the isoprenoid pathway also leads to the construction of an Escherichia coli strain that produces a high titer of taxadiene-the first committed intermediate for taxol biosynthesis. These examples of synthetic biology demonstrate the versatility of metabolic engineering to bring new solutions to our health needs.

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