Study Reveals How to Improve Beta-carotene Production
2013-10-18
Beta-carotene is a kind of natural tetraterpenes pigment and known to exhibit a number of pharmacological and nutraceutical benefits to human health. Nowadays, beta-carotene has also gained increasing attention in food and feed additives, cosmetics, and health food and pharmaceutical industries. Metabolic engineering of beta-carotene biosynthesis in Saccharomyces cerevisiae has been attracting the interest of many science researchers.
LI Qian, under the supervison of Prof. ZHANG Yansheng from Wuhan Botanical Garden, achieved much improvement in beta-carotene production in S. cerevisiae by transferring the crtI (phytoene desaturase) gene and crtYB (phytoene synthase) gene from Xanthophyllomyces dendrorhous and improving the codon usage of some specific site optimization of these two genes, in which five codons of crtI and eight codons of crtYB were rationally mutated. At the same time, the HMGR (3-hydroxy-3-methylglutaryl coenzyme A reductase) from Staphylococcus aureus, which is the enzyme that is the major rate-limiting enzyme in MVA (mevalonate) pathway, got overexpressed in S. cerevisiae. As the result, the growth of the strains wasn’t infected.
Results were published in FEMS Microbiology Letters (2013, 345(2), 94-101) entitled “Enhancing beta-carotene production in Saccharomyces cerevisiae by metabolic engineering”.
The low usage codons (＜15%) of (a) crtI and (b) crtYB gene from Xanthophyllomyces dendrorhous (Image by LI Qian)
Colors of different carotenoids-producing S. cerevisiae transformants. (a) WAT11/pRS406, (b) WAT11/pRS406W, (c) WAT11/pRS406M, (d) WAT11/pRS406M-HIS, (e) WAT11/pRS406M-tHMG1, and (f) WAT11/pRS406M-mva. These transformants were grown in YNB–2% glucose medium. (Image by LI Qian)
