The Biosynthesis Of Hydroxy Fatty Acid Based On Rhodospridium Toruloides

Fatty acids are an important part of lipid,among which C16 and C18 fatty acids account for more than 90% of the total fatty acids.In addition to C16 and C18 fatty acids,lipids also have other trace fatty acids.Fatty acids are a class of highly diversified molecules with variable chain length,number of double bonds and hydroxylation sites.They and their derivatives have their own application value.The four excellent oleaginous yeasts,Rhodospridium toruloides,Trichosporon cutaneum,Lipomyces starkeyi and Cryptococcus curvatus were selected to analysis fatty acid profile of oleaginous yeast.Then R.toruloides was been a research object to investigate the influence of carbon sources,temperature,and pH on their fatty acid profiles.Finally,R.toruloides was been a chassis cell to construct the producing hydroxy fatty acids strains.Results as following:1)Analyzed the fatty acid composition of R.toruloides,T.cutaneum,L.starkeyi and C.curvatus indicating that the lipid of oleaginous yeast is composed of at least 18 fatty acids,namely hexanoic acid,heptanoic acid,octanoic acid,nonanoic acid,decanoic acid,lauric acid,cinnamic acid,pentadecanoic acid,palmitoleic acid,palmitic acid,10-heptadecenoic acid,Heptacolic acid,oleic acid,stearic acid,eicolic acid,dicarboxylic acid,Tricosanoicacid acid,eicosanoic acid,lignoceric acid.Linoleic acid,pentacosanoic acid,hexacosanoic acid were only detected in R.toruloides,L.starkeyi and C.curvatus.2)The thesis studied the effects of commonly used carbon sources,temperature and pH on the fatty acid composition of R.toruloides.It was found that the carbon source and temperature had a greater influence on the fatty acid composition of lipids,and mainly affect the composition ratio of C16 and C18 fatty acids,SCFA and VLCFA in grease.But the initial pH value affected the yield and content of lipids.3)In this paper,the expression vectors of 10-hydroxystearic acid and ricinoleic acid were constructed by introducing codon-optimized oleic acid hydrase and 12-hydroxylase.And we successfully obtained ricinoleic acid producing strain,in which ricinoleic acid accounted for 0.06% of the total fatty acids.