Overexpression of ZWF1 and POS5 improves carotenoid biosynthesis in recombinant Saccharomyces cerevisiae

Recombinant Saccharomyces cerevisiae expressing exogenous carotenogenic genes can synthesize carotenoids. NADPH is a key cofactor for carotenoid biosynthesis, while glucose-6-phosphate dehydrogenase (Zwf1) and an NADH kinase (Pos5) are the two main NADPH-supplying sources in S. cerevisiae. Here, the effect of ZWF1 and POS5 overexpression on carotenoid yield in recombinant S. cerevisiae was explored. The initial carotenogenic strain Sc-EYBIH+I which expressed crtE, crtYB, crtI, cHMG1 and another copy of crtI could synthesize 1.35 +/- 0.13 mg l(-1) of lycopene and 0.32 +/- 0.02 mg l(-1) of beta-carotene. When ZWF1 was overexpressed (Sc-EYBIZH+I), glucose-6-phosphate dehydrogenase activity increased by 103-fold, the transcription level of crtE and crtI increased significantly, the lycopene and beta-carotene yield increased to 2.29 +/- 0.06 and 0.38 +/- 0.02 mg l(-1) respectively. When POS5 was overexpressed (Sc-EYBIPH+I), NAD kinase activity increased by 5.5-fold, the transcription level of crtE, crtYB and crtI increased obviously, the lycopene and beta-carotene yield increased to 2.50 +/- 0.11 and 0.53 +/- 0.03 mg l(-1) respectively. Therefore, improvement of NADPH supply contributed to carotenoids biosynthesis in S. cerevisiae and overexpression of POS5 was more effective than overexpression of ZWF1. This study provides a new strategy for enhancing carotenoid biosynthesis.