β-胡萝卜素是一种天然色素，属于四萜类化合物，有很高的药理学及营养学价值，现在已广泛应用于医药、保健品、食品添加剂及化妆品等行业。构建高效合成β-胡萝卜素的微生物菌株具有良好的应用前景。
中国科学院武汉植物园天然产物合成生物学学科组硕士研究生李倩在章焰生研究员的指导下，于酿酒酵母中重构了β-胡萝卜素的生物合成途径，将来源于红发夫酵母中与β-胡萝卜素合成相关的基因crtYB（八氢番茄红素合成酶及番茄红素环化酶基因）和crtI（八氢番茄红素脱氢酶基因）转入酿酒酵母，并对这两个基因进行了密码子的优化；同时通过过量表达异戊稀代谢途径中的关键限速酶HMGR（3-羟基-3-甲基戊二酰辅酶A还原酶）基因，发现菌株β-胡萝卜素的产量提高了很多，且对酿酒酵母的生长无影响，最终得到具备高效合成β-胡萝卜素能力的酿酒酵母工程菌株。
该研究为酿酒酵母大规模生产β-胡萝卜素提供依据，也为酿酒酵母中萜类物质生物合成及代谢工程改造提供了一定的理论基础。相关研究结果发表在国际学术期刊FEMS Microbiology Letters（2013， 345(2)， 94-101）上（生物谷Bioon.com）。
生物谷推荐的英文摘要
FEMS Microbiology Letters DOI: 10.1111/1574-6968.12187
Enhancing beta-carotene production in Saccharomyces cerevisiae by metabolic engineering
Qian Li1，2， Zhiqiang Sun1，2， Jing Li1，2， Yansheng Zhang1，*
Beta-carotene is known to exhibit a number of pharmacological and nutraceutical benefits to human health. Metabolic engineering of beta-carotene biosynthesis in Saccharomyces cerevisiae has been attracting the interest of many researchers. A previous work has shown that S. cerevisiae successfully integrated with phytoene synthase (crtYB) and phytoene desaturase (crtI) from Xanthophyllomyces dendrorhous could produce beta-carotene. In the present study， we achieved around 200% improvement in beta-carotene production in S. cerevisiae through specific site optimization of crtI and crtYB， in which five codons of crtI and eight codons of crtYB were rationally mutated. Furthermore， the effects of the truncated HMG-CoA reductase (tHMG1) from S. cerevisiae and HMG-CoA reductase (mva) from Staphylococcus aureus on the production of beta-carotene in S. cerevisiae were also evaluated. Our results indicated that mva from a prokaryotic organism might be more effective than tHMG1 for beta-carotene production in S. cerevisiae.
