The role of acyl-CoA thioesterase ACOT8I in mediating intracellular lipid metabolism in oleaginous fungus Mortierella alpina
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Thioesterases (TEs) play an essential role in the metabolism of fatty acids (FAs). To explore the role of TEs in mediating intracellular lipid metabolism in the oleaginous fungus Mortierella alpina, the acyl-CoA thioesterase ACOT8I was overexpressed. The contents of total fatty acids (TFAs) were the same in the recombinant strains as in the wild-type M. alpina, whilst the production of free fatty acids (FFAs) was enhanced from about 0.9% (wild-type) to 2.8% (recombinant), a roughly threefold increase. Linoleic acid content in FFA form constituted about 9% of the TFAs in the FFA fraction in the recombinant strains but only about 1.3% in the wild-type M. alpina. The gamma-linolenic acid and arachidonic acid contents in FFA form accounted for about 4 and 25%, respectively, of the TFAs in the FFA fraction in the recombinant strains, whilst neither of them in FFA form were detected in the wild-type M. alpina. Overexpression of the TE ACOT8I in the oleaginous fungus M. alpina reinforced the flux from acyl-CoAs to FFAs, improved the production of FFAs and tailored the FA profiles of the lipid species.
KeywordsMortierella alpina ACOT8I Free fatty acids Overexpression Fatty acid profiles
JG carried out the experiments and drafted the manuscript. HC and BY performed the complementation experiments. HC and YQC analyzed the data and helped to draft the manuscript. WC and HZ conceived and coordinated the study and revised the manuscript. All authors read and approved the final manuscript.
Compliance with ethical standards
This research was supported by the National Natural Science Foundation of China (nos. 31571810, 31530056); the Fundamental Research Funds for the Central Universities (no. JUSRP51702A); the program of “Collaborative innovation center of food safety and quality control in Jiangsu Province”.
Conflict of interest
The authors declare that they have no competing interests.
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