新型可再生工业用油脂的代谢工程

Metabolic Engineering to Produce Novel Renewable Industrial Fatty Acids in Oilseeds

植物种子油是一种可再生资源,亦用作生物燃油和化学工业原料.一些野生植物能高水平合成积累羟化、环氧化和共轭脂肪酸等具有重要工业应用价值的特异脂肪酸.催化这些特异脂肪酸合成的酶主要是类脂肪酸去胞和酶2(类FAD2).由特异脂肪酸合成到三酰基甘油脂(TAG)形成还需要酰基转移酶(如DGAT)的参与.在油料作物种子中表达类FAD2酶及其相关基因(如DGAT),已培育出了能合成积累一定含量特异脂肪酸的工程油料品系,为基于农作物生产高附加值工业用油脂开辟了新途径.本文论述了参与特异脂肪酸生物合成途径的关键酶基因、油料作物代谢工程策略,以及应用工程油料作物大规模生产重要工业用脂肪酸的研究进展、存在问题和应用前景等.

Plant oilseeds represent renewable sources, and also serve as both biofuel and chemical feedstock. A number of non-agronomic plant species synthesize and accumulate high levels of unusual fatty acids including hydroxy, epoxy and conjugated fatty acids in their seeds, which are extremely valuable for industrial applications. The fatty acid desaturase 2 （FAD2）-like enzymes are the major enzymes that catalyze the synthesis of many industrial-value fatty acids in plant seeds. Acyhransferases such as DGAT1 and DGAT2 are a group of key enzymes responsible for the channel of unusual fatty acids into storage in triaeylglycerols （TAG）. Metabolic engineering by seed-specific coexpressing FAD2-like enzyme and other related genes （e. g. DGATs ） has developed the novel engineered oilseed lines that are capable of synthesizing a moderate amount of the target fatty acids in their seeds, opening up a new way for the crop-based production of high-value industrial lipids. Here, we provide an overview of unusual fatty acids biosynthesis pathway and the associated key enzymes, describe the strategies for metabolic engineering of unusual fatty acids in oilseeds, and highlight the recent advances in this field. We also discussed the future perspectives in the commercial production of industrial-value fatty acids by transgenie oil crops along with some of the technical hurdles encountered so far.