Metabolic Engineering Of De Novo Synthesis Of Nervonic Acid By Yarrowia Lipolytica

Fatty acids and their derivatives have a wide range of application prospects:nervonic acid(cis-tetracos-15-enoic acid)is the main very long chain monounsaturated fatty acid in mammalian brain white matter,which plays an important role in the treatment of nerve division and nerve development.At present,fatty acids and their derivatives are mainly obtained by natural extraction or chemical synthesis.These methods are limitated by natural resources and production costs,thus the development of biosynthesis methods become important application value and theoretical significance.In this study,the de novo synthetic pathway of nervonic acid was constructed in Yarrowia lipolytica for the first time by means of synthetic biology,and the yield of nervonic acid was further improved by metabolic engineering and fermentation optimization.The biosynthesis of nervonic acid is considered to be realized from oleic acid through fatty acid prolongation.In the study of the de novo synthesize nervonic acid by Y.lipolytica,we explored the adaptability of exogenous gene and chassis cell,and combined with promoter engineering,gene expression optimization and fermentation medium selection.The effective strategy of improving the production of nervonic acid by Y.lipolytica is proposed.First of all,we integrated the previous experience of our group on fatty acid prolongation,and explored the effect of fatty acid elongase on the synthesis of nervonic acid in cells.It was found that the coexpression of MaELO3,AtKCS,CraKCS and CgKCS is used for heterologous synthesis of nervonic acid by Y.lipolytica.In order to further improve the production of nervonic acid,this study introduced Δ15 desaturase into the cell,and achieved the increase of the content of neural acid by optimizing the expression of fatty acid extender and desaturase.In addition,we also found that the engineering strain can extend the exogenous fatty acids,due to the extension occurs at the carboxyl end of fatty acids,so the added ω-9 cis enoic acid can be extended to C24 therewith nervonic acid biosynthesized.Moreover,the addition of colleseed oil greatly improved the production of nervonic acid,which reached 59.1 mg/L in flaskIn this study,we first reported the de novo synthesis of nervonic acid by oleaginous yeast Y.lipolytica,and further improved the production of nervonic acid by metabolic engineering.This study offer significante reference value for the production of super long chain fatty acids by other yeast.