代谢工程构建重组耶氏解脂酵母生产中长链聚羟基脂肪酸酯

Medium-chain-length polyhydroxyalkanoates (mcl-PHAs) are a large class of biopolymers that have attracted extensive attention as renewable and biodegradable bio-plastics. They are naturally synthesized via fatty acid de novo biosynthesis pathway or β-oxidation pathway from Pseudomonads. The unconventional yeast Yarrowia lipolytica has excellent lipid/fatty acid catabolism and anabolism capacity depending of the mode of culture. Nevertheless, it cannot naturally synthesize PHA, as it does not express an intrinsic PHA synthase. Here, a genetically modified strain of Y. lipolytica was constructed by heterologously expressing PhaC1 gene from P. aeruginosa PAO1 encoding PHA synthase with a peroxisomal signal (PTS1) at the C terminal. The gene was coden optimized and linked onto the vector of pINA1312 to construct pINA1312-oPHA. The expression cassette derived from pINA1312-oPHA was integrated onto the genome randomly through zeta element above the vector resulting strain PSOC. The recombinant yeast of PSOC barely produced mcl-PHA when grew in YPD, but can produce 0.67% DCW of PHA after 72 cultivation in YPD medium containing 0.5% oleic acid. Furthermore, when PSOC was grown in the medium containing triolein, PHA accumulated up to 1.51% DCW. It successfully demonstrated the potential use of Y. lipolytica as a promising microbial cell factory for mcl-PHA production, which laid the foundation for using food waste that contains lipids and other essential nutrients to produce mcl-PHA.