(191an) Construction of a Zeaxanthin Biosynthetic Pathway As the Base for Crocin Synthesis in Saccharomyces Cerevisiae

Crocin is a pharmacologically active carotenoid pigment mainly present in the stigmas of Crocus sativus. It has been well explored in experimental animal models of cognitive impairments, depression, anxiety and epilepsy.But extraction from plant is the only way for its production. Crocin synthetic pathway in Crocus sativus shown that four steps progressed from β-carotene to crocin. The intermediate productss are zeaxanthin, crocetin dialdehyde, crocetin, and the final crocin.

Synthetic biology provides many novel approaches for microbiology that many plant intermediate products can be produce in microbe. Our study use correlation technique to construct a new system aimed to produce crocin.

Based on a high-level β-carotene production yeast strain from Yu Hongwei, our main work is construct a high-level zeaxanthin product strain. β-carotene hydroxylase(BCH), which is the key enzyme for the reaction, can be found in many species. We worked on 8 bch genes ,which were screened out and condon optimized. Then we set up the a best zeaxanthin biosynthesis system in yeast cell.

Of the next three steps to produce crocin, only one reaction was not clear about its enzyme and conditions. Our study also do some work to find out the undiscovered enzyme and try to assembly the other components for steps, to prepare for the crocin-producing yeast strain.