利用代谢工程改造解脂耶式酵母合成角黄素

Modification of Yarrowia lipolytica for the biosynthesis of canthaxanthin by metabolic engineering

角黄素是一种橙红色的二酮类胡萝卜素,作为着色剂和抗氧化剂被广泛应用于食品、饲料和化妆品等领域。为生产高水平的角黄素,改造解脂耶氏酵母,通过增加内源牻牛儿基牻牛儿基焦磷酸供给、引入外源β-胡萝卜素生物合成路径、过表达DNA修复基因rad52、增强还原能量及前体物供应,构建了高产β-胡萝卜素的工程菌株。进一步引入副球菌来源的β-胡萝卜素酮化酶基因,增加基因拷贝数及β-胡萝卜素的前体物供应,回补营养缺陷型标签,构建的工程菌株在摇瓶条件下合成了301.1 mg/L的角黄素。实验结果报告了目前微生物合成角黄素的最高摇瓶产量,可为角黄素的商业化生产提供理论指导,同时也为其它类胡萝卜素的生物合成提供理论依据。

Canthaxanthin,an orange-red ketocarotenoid,is widely used as a colorant and antioxidant in food,feed,and cosmetic industries.In order to produce high levels of canthaxanthin,Yarrowia lipolytica was modified to construct a highβ-carotene-producing strain achieved by enhancing the flux of endogenous geranylgeranyl diphosphate,strengthening the exogenousβ-carotene biosynthetic pathway,overexpressing the DNA repair gene rad52,and enhancing NADPH supply and precursors.The study further introduced aβ-carotene ketolase gene from Paracoccus sp.,increased gene copy number and the supply ofβ-carotene precursors,and complemented auxotrophic markers.The final engineered strain synthesized 301.1 mg/L of canthaxanthin under shake-flask fermentation conditions.The results of the experiment were reported the highest shake-flask production of canthaxanthin by microorganisms to date,providing theoretical guidance for the commercial production of canthaxanthin and serving as a reference for the synthesis of other carotenoids.