Identification of Δ9-Elongation Activity from Thraustochytrium aureum by Heterologous Expression in Pichia pastoris

• Published in: Biotechnology and bioprocess engineering 2008-10, Vol.13 (5), p.524-532
• Main Authors: Lee, J.C. (Inha University, Incheon, Republic of Korea), Anbu, Periasamy (Inha University, Incheon, Republic of Korea), Kim, W.H. (Inha University, Incheon, Republic of Korea), Noh, M.J. (Inha University, Incheon, Republic of Korea), Lee, S.J. (Molecular Bioprocess Research Centre, Jeonbuk Branch Institute, KRIBB, Jeongeup, Republic of Korea), Seo, J.W. (Molecular Bioprocess Research Centre, Jeonbuk Branch Institute, KRIBB, Jeongeup, Republic of Korea), Hur, B.K. (Inha University, Incheon, Republic of Korea), E-mail: [e-mail]
• Format: Article
• Language: English
• Subjects: ACIDE GRAS POLYINSATURE; ACIDOS GRASOS POLIINSATURADOS; Biotechnology; Chemistry; Chemistry and Materials Science; eicosadienoic acid; eicosatrienoic acid; elongase; Industrial and Production Engineering; POLYUNSATURATED FATTY ACIDS; Thraustochytrium aureum
• ISSN: 1226-8372; 1976-3816
• DOI: 10.1007/s12257-008-0032-5

The Δ9-elongase isolated from Thraustochytrium aureum, which contains a high level of polyunsaturated fatty acids (PUFAs), was demonstrated to be associated with the synthesis of C20 PUFAs. The TaELO gene contains a 825 bp ORF that encodes a protein of 274 amino acids that shares a high similarity with other PUFA elongases. The expression of the TaELO gene in Pichia pastoris resulted in the elongation of linoleic acid (LA, C18:2; n-6) and α-linolenic acid (ALA, C18:3; n-3) to eicosadienoic acid (EDA, C20:2; n-6) and eicosatrienoic acid (ETrA, C20:3; n-3), respectively. The endogenous conversion rate of LA and ALA to EDA and ETrA was 32.68 and 38.57%, respectively. In addition, TaELO was also able to synthesize eicosenoic acid (C20:1; n-9) from oleic acid (OA, C18:1; n-9), even though the conversion level was low (2.81%). Furthermore, TaELO was able to carry out the Δ6-elongation of γ-linolenic acid (GLA, C18:3; n-6) to dihomo-γ-linolenic acid (DGLA, C20:3; n-6) and Δ5-elongation of eicosapentaenoic acid (EPA, C20:5; n-3) to docosapentaenoic acid (DPA, C22:5; n-3). The conversion rate of GLA to DGLA and EPA to DPA were 93 and 28.36%, respectively. The TaELO protein was confirmed to have multifunctional activities, such as Δ9, Δ6, and Δ5-elongations as well as the elongation of monounsaturated fatty acid.