Cloning and Expression of Phytoene Desaturase Gene from Undaria pinnatifida Suringar

The phytoene desaturase is a key enzyme involved in the carotenoids biosynthesis pathway, which catalyzes the conversion of zeta-carotene from phytoene. Undaria pinnatifida Suringar is an edible economic brown algae that produces high concentrations of fucoxanthin. In this study, the PDS gene (UpPDS) was isolated and characterized from U. pinnatifida, and the full-length cDNA sequence was 1707 bp in length and encoded 568 amino acid residues. Furthermore, the putative protein sequence showed a high homology to the PDS from other known plants. Phylogenetic analysis showed that the UpPDS was more related to that of brown algae compared to other species. By heterologous complementation and high-performance liquid chromatography analysis, desaturation activity of recombinant UpPDS was confirmed by production of zeta-carotene in engineering E. coli co-transformed with crtE, crtB and UpPDS. The L-9(3(4)) orthogonal test was used to optimize zeta-carotene fermentation conditions of the engineering bacteria. The results showed that temperature had the most significant effect on zeta-carotene production, the maximal yield of zeta-carotene could reach 5.0mg/L under the optimal conditions.