Fig. 5

Functional identification of PsCrtY as a lycopene cyclase. (a) HPLC analysis (460 nm) of β-carotene production through co-expression of PsCrtY with the lycopene biosynthetic enzymes. (i) E. coli BL21(DE3)/pAC-LYCipi (negative control) producing lycopene (retention time: 14.8 min), (ii) E. coli BL21(DE3)/pAC-LYCipi+pOKF91 (pAC-LYCipi+PsCrtY) producing β-carotene (retention time: 13.3 min), (iii) E. coli BL21(DE3)/pAC-BETAipi (positive control) producing β-carotene (retention time: 13.3 min). Color change of harvested cells due to the co-expression of PsCrtY with pAC-LYCipi in E. coli BL21(DE3) is shown on the right. (b) A comparison of the UV spectra of β-carotene produced by E. coli BL21(DE3)/pAC-LYCipi+pOKF91 with β-carotene produced by the positive control and lycopene produced by the negative control