title: Improved eicosapentaenoic acid production in Pythium splendens RBB-5 based on metabolic regulation analysis.
abstract: Eicosapentaenoic acid (EPA) is an essential polyunsaturated fatty acid for human beings. At present, the production of commercially available long-chain polyunsaturated fatty acids, mainly from wild-caught ocean fish, is struggling to meet the increasing demand for EPA. Production of EPA by microorganisms may be an alternative, effective and economical method. The oleaginous fungus Pythium splendens RBB-5 is a potential source of EPA, and thanks to the simple culture conditions required, high yields can be achieved in a facile manner. In the study, lipid metabolomics was performed in an attempt to enhance EPA biosynthesis in Pythium splendens. Synthetic, metabolic regulation and gene expression analyses were conducted to clarify the mechanism of EPA biosynthesis, and guide optimization of EPA production. The results showed that the Δ6desaturase pathway is the main EPA biosynthetic route in this organism, and ∆6, ∆12and Δ17desaturases are the rate-limiting enzymes. All the three desaturase genes were separately introduced into the parent strain to increase the flow of fatty acids into the Δ6desaturase pathway. Enhanced expression of these key enzymes, in combination with improved regulation of metabolism, resulted in a maximum yield of 1.43 g/L in the D12 transgenic strain, which represents a tenfold increase over the parent strain before optimization. This is the higher EPA production yield yet reported for a microbial system. Our findings may allow the production of EPA at an industrial scale, and the strategy employed could be used to increase the production of EPA or other lipids in oleaginous microorganisms.
authors.affiliation: Institute of Resource Biology and Biotechnology, Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, No. 1037 Luoyu Road, Wuhan, 430074, China.|Department of Environmental and Bio-chemical Engineering, Wuhan Vocational College of Software and Engineering, Wuhan, 430205, China.|Key Laboratory of Molecular Biophysics, Ministry of Education, Wuhan, 430074, China.|Wuhan Institute of Biotechnology, Wuhan, 430075, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Ren
authors.affiliation: Institute of Resource Biology and Biotechnology, Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, No. 1037 Luoyu Road, Wuhan, 430074, China.|Key Laboratory of Molecular Biophysics, Ministry of Education, Wuhan, 430074, China.|Wuhan Institute of Biotechnology, Wuhan, 430075, China.
authors.forename: Pengpeng
authors.initials: P
authors.lastname: Zhou
authors.affiliation: Institute of Resource Biology and Biotechnology, Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, No. 1037 Luoyu Road, Wuhan, 430074, China.|Key Laboratory of Molecular Biophysics, Ministry of Education, Wuhan, 430074, China.|Wuhan Institute of Biotechnology, Wuhan, 430075, China.
authors.forename: Yuanmin
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Institute of Resource Biology and Biotechnology, Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, No. 1037 Luoyu Road, Wuhan, 430074, China.|Key Laboratory of Molecular Biophysics, Ministry of Education, Wuhan, 430074, China.|Wuhan Institute of Biotechnology, Wuhan, 430075, China.
authors.forename: Ruijiao
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Institute of Resource Biology and Biotechnology, Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, No. 1037 Luoyu Road, Wuhan, 430074, China. yulongjiang@hust.edu.cn.|Key Laboratory of Molecular Biophysics, Ministry of Education, Wuhan, 430074, China. yulongjiang@hust.edu.cn.|Wuhan Institute of Biotechnology, Wuhan, 430075, China. yulongjiang@hust.edu.cn.
authors.forename: Longjiang
authors.initials: L
authors.lastname: Yu
mesh_terms: D053898:Biosynthetic Pathways / Q000235:genetics*; D015118:Eicosapentaenoic Acid / Q000378:metabolism*; D044943:Fatty Acid Desaturases / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D011775:Pythium / Q000235:genetics / Q000378:metabolism*
chemical_list: D015118:Eicosapentaenoic Acid; D044943:Fatty Acid Desaturases
keywords: EPA synthesis optimization; Eicosapentaenoic acid; Fatty acid metabolism; Pythium splendens; Transgenic strains