Production of eicosapentaenoic acid by application of a delta-6 desaturase with the highest ALA catalytic activity in algae

Abstract Dunaliella salina is a unicellular green alga with a high α-linolenic acid (ALA) level, but a low eicosapentaenoic acid (EPA) level. In a previous analysis of the catalytic activity of delta 6 fatty acid desaturase (FADS6) from various species, FADS6 from Thalassiosira pseudonana (TpFADS6),...

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Main Authors: Haisu Shi, Xue Luo, Rina Wu, Xiqing Yue
Format: Article
Language:English
Published: BMC 2018-01-01
Series:Microbial Cell Factories
Subjects:
Online Access:http://link.springer.com/article/10.1186/s12934-018-0857-3
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author Haisu Shi
Xue Luo
Rina Wu
Xiqing Yue
author_facet Haisu Shi
Xue Luo
Rina Wu
Xiqing Yue
author_sort Haisu Shi
collection DOAJ
description Abstract Dunaliella salina is a unicellular green alga with a high α-linolenic acid (ALA) level, but a low eicosapentaenoic acid (EPA) level. In a previous analysis of the catalytic activity of delta 6 fatty acid desaturase (FADS6) from various species, FADS6 from Thalassiosira pseudonana (TpFADS6), a marine diatom, showed the highest catalytic activity for ALA. In this study, to enhance EPA production in D. salina, FADS6 from D. salina (DsFADS6) was identified, and substrate specificities for DsFADS6 and TpFADS6 were characterized. Furthermore, a plasmid harboring the TpFADS6 gene was constructed and overexpressed in D. salina. Our results revealed that EPA production reached 21.3 ± 1.5 mg/L in D. salina transformants. To further increase EPA production, myoinositol (MI) was used as a growth-promoting agent; it increased the dry cell weight of D. salina transformants, and EPA production reached 91.3 ± 11.6 mg/L. The combination of 12% CO2 aeration with glucose/KNO3 in the medium improved EPA production to 192.9 ± 25.7 mg/L in the Ds-TpFADS6 transformant. We confirmed that the increase in ALA was optimal at 8 °C; the EPA percentage reached 41.12 ± 4.78%. The EPA yield was further increased to 554.3 ± 95.6 mg/L by supplementation with 4 g/L perilla seed meal (PeSM), 500 mg/L MI, and 12% CO2 aeration with glucose/KNO3 at varying temperatures. EPA production and the percentage of EPA in D. salina were 343.8-fold and 25-fold higher than those in wild-type D. salina, respectively. Importance FADS6 from Thalassiosira pseudonana, which demonstrates high catalytic activity toward α-linolenic acid, was used to enhance EPA production by Dunaliella salina. Transformation of FADS6 from Thalassiosira pseudonana into Dunaliella salina with myoinositol, CO2, low temperatures, and perilla seed meal supplementation substantially increased EPA production in Dunaliella salina to 554.3 ± 95.6 mg/L. Accordingly, D. salina could be a potential alternative source of EPA and is suitable for its large-scale production.
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spelling doaj.art-e63a66a1c1054fd8bccb44e2ecda7e3f2022-12-21T23:18:24ZengBMCMicrobial Cell Factories1475-28592018-01-0117111510.1186/s12934-018-0857-3Production of eicosapentaenoic acid by application of a delta-6 desaturase with the highest ALA catalytic activity in algaeHaisu Shi0Xue Luo1Rina Wu2Xiqing Yue3College of Food Science, Shenyang Agricultural UniversityCollege of Food Science, Shenyang Agricultural UniversityCollege of Food Science, Shenyang Agricultural UniversityCollege of Food Science, Shenyang Agricultural UniversityAbstract Dunaliella salina is a unicellular green alga with a high α-linolenic acid (ALA) level, but a low eicosapentaenoic acid (EPA) level. In a previous analysis of the catalytic activity of delta 6 fatty acid desaturase (FADS6) from various species, FADS6 from Thalassiosira pseudonana (TpFADS6), a marine diatom, showed the highest catalytic activity for ALA. In this study, to enhance EPA production in D. salina, FADS6 from D. salina (DsFADS6) was identified, and substrate specificities for DsFADS6 and TpFADS6 were characterized. Furthermore, a plasmid harboring the TpFADS6 gene was constructed and overexpressed in D. salina. Our results revealed that EPA production reached 21.3 ± 1.5 mg/L in D. salina transformants. To further increase EPA production, myoinositol (MI) was used as a growth-promoting agent; it increased the dry cell weight of D. salina transformants, and EPA production reached 91.3 ± 11.6 mg/L. The combination of 12% CO2 aeration with glucose/KNO3 in the medium improved EPA production to 192.9 ± 25.7 mg/L in the Ds-TpFADS6 transformant. We confirmed that the increase in ALA was optimal at 8 °C; the EPA percentage reached 41.12 ± 4.78%. The EPA yield was further increased to 554.3 ± 95.6 mg/L by supplementation with 4 g/L perilla seed meal (PeSM), 500 mg/L MI, and 12% CO2 aeration with glucose/KNO3 at varying temperatures. EPA production and the percentage of EPA in D. salina were 343.8-fold and 25-fold higher than those in wild-type D. salina, respectively. Importance FADS6 from Thalassiosira pseudonana, which demonstrates high catalytic activity toward α-linolenic acid, was used to enhance EPA production by Dunaliella salina. Transformation of FADS6 from Thalassiosira pseudonana into Dunaliella salina with myoinositol, CO2, low temperatures, and perilla seed meal supplementation substantially increased EPA production in Dunaliella salina to 554.3 ± 95.6 mg/L. Accordingly, D. salina could be a potential alternative source of EPA and is suitable for its large-scale production.http://link.springer.com/article/10.1186/s12934-018-0857-3Delta 6 fatty acid desaturaseEicosapentaenoic acidPerilla seed meal
spellingShingle Haisu Shi
Xue Luo
Rina Wu
Xiqing Yue
Production of eicosapentaenoic acid by application of a delta-6 desaturase with the highest ALA catalytic activity in algae
Microbial Cell Factories
Delta 6 fatty acid desaturase
Eicosapentaenoic acid
Perilla seed meal
title Production of eicosapentaenoic acid by application of a delta-6 desaturase with the highest ALA catalytic activity in algae
title_full Production of eicosapentaenoic acid by application of a delta-6 desaturase with the highest ALA catalytic activity in algae
title_fullStr Production of eicosapentaenoic acid by application of a delta-6 desaturase with the highest ALA catalytic activity in algae
title_full_unstemmed Production of eicosapentaenoic acid by application of a delta-6 desaturase with the highest ALA catalytic activity in algae
title_short Production of eicosapentaenoic acid by application of a delta-6 desaturase with the highest ALA catalytic activity in algae
title_sort production of eicosapentaenoic acid by application of a delta 6 desaturase with the highest ala catalytic activity in algae
topic Delta 6 fatty acid desaturase
Eicosapentaenoic acid
Perilla seed meal
url http://link.springer.com/article/10.1186/s12934-018-0857-3
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