title: Overexpression of ZWF1 and POS5 improves carotenoid biosynthesis in recombinant Saccharomyces cerevisiae.
abstract: 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 β-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 β-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 β-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.
  
  
  CONCLUSIONS
  NADPH is a key cofactor for carotenoid biosynthesis. Glucose-6-phosphate dehydrogenase (Zwf1) and an NADH kinase (Pos5) are effective NADPH-supplying sources in Saccharomyces cerevisiae. When ZWF1 and POS5 were overexpressed in a carotenoid-producing S. cerevisiae strain individually, the total yield of lycopene and β-carotene increased by 59·9% and 81·4%, respectively, and the final product β-carotene yield increased by 18·8% and 65·6% respectively. This suggests the improvement of NADPH supply as a useful strategy for carotenoids biosynthesis.
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China.|Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.|Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, China.
authors.forename: X
authors.initials: X
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China.|Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.|Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, China.
authors.forename: F
authors.initials: F
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China.|Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.
authors.forename: W
authors.initials: W
authors.lastname: Zhan
mesh_terms: D002338:Carotenoids / Q000096:biosynthesis*; D005954:Glucosephosphate Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D000077276:Lycopene; D024101:Mitochondrial Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D009249:NADP / Q000737:chemistry*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics; D019207:beta Carotene / Q000096:biosynthesis*
chemical_list: D024101:Mitochondrial Proteins; D029701:Saccharomyces cerevisiae Proteins; D019207:beta Carotene; D002338:Carotenoids; D009249:NADP; D005954:Glucosephosphate Dehydrogenase; D017853:Phosphotransferases (Alcohol Group Acceptor); C060670:POS5 protein, S cerevisiae; D000077276:Lycopene
keywords: NADPH supply; POS5; Saccharomyces cerevisiae; ZWF1; lycopene; β-carotene