The Synthesis Of ?-hydroxy Fatty Acids By Metabolic Engineering Escherichia Coli

Hydroxy fatty acids are natural organic compounds that are existing in nature.The hydroxyl and carboxyl functional groups on the carbon chain of ?-hydroxy fatty acids provide special properties that make hydroxy fatty acids widely used in industrial and medical fields.In this study,a whole cell biocatalysis strategy has been established to increase?-hydroxydecanoic acid production based on AlkBGT hydroxylation system from Pseudomonas putida GPo1.Firstly,the ribosome binding site between each protein of AlkBGT was optimized to get the optimized expression plasmid pBGT,and then the synthesis system was further optimized by using decanoic acid as a substrate.Then,blocking the?-oxidation of fatty acids and enhancing the transportation of fatty acids were also investigated.When fadE and fadD were deleted,the consumption of fatty acids decreased,however,the yield of ?-hydroxydecanoic acid enhanced significantly to 276.23 mg/L,and the conversion reached 69.83%.Additionally,to enhance the fatty acids transport capability of E.coli,the plasmid pBGT-fadL was constructed.As a result,the concentration and conversion of ?-hydroxydecanoic acid in NH03(pBGT-fadL)increased to 309.98 mg/L and 85.65%,respectively.In addition,the bio-catalytic stragategy also showed a good performance on octanoic acid and dodecanoic acid.In NH03(pBGT-fadL),the accumulation of?-hydroxyoctanoic acid and ?-hydroxydodecanoic acid reached 275.48 mg/L and 249.03 mg/L,the conversion was 62.99%and 58.69%respectively.This study demonstrated that AlkBGT coupling with the native FadL is an efficient strategy to catalyze ?-hydroxydecanoic acid from decanoic acid in the fadE and fadD mutant E.coli strains.