| Summary: | 碩士 === 國立中興大學 === 生命科學系所 === 102 === In the post-genome era, synthetic biology is a new approach to design a new biological system or to re-design natural biological systems for new function. Carotenoids, including β-carotene, canthaxanthin and zeaxanthin, are antioxidants and the downstream product, astaxanthin, is the stronger one but the lower contestant. We propose to develop a “cell factory” for producing carotenoids, via a synthetic biology tool, PGASO, that can simultaneously transform and regulatory express multiple gene in the yeast. In this proposal, engineering of the carotenogenic pathway will be achieved in a thermo- and toxin-tolerant yeast, Kluyveromyces marxianus KY3. The suitable Astaxanthin synthesis genes, including crtE, crtYB, crtI, tHMG1, crtS, crtR, bkt, and chyb, from suitable host, such as Xanthophyllomyces dendrorhous and green algae (Chlamydomonas reinhardtii, Chlorella zofingiensis, and Haematococcus pluvialis) were selected. We check the conformation of the engineered strain Cz30 via high performance liquid chromatography (HPLC) and it contains β-carotene and canthaxanthin in the red color cell. Compared to the wild type strain, the engineered strain showed higher ethanol tolerance and higher bio-ethanol productivity, in addition to producing carotenoids. The results suggested that the production of antioxidant carotenoids can improve toxin tolerance, damage recovering, and cell membrane maintenance via free radical removal. Furthermore, the strain could utilize glycerol, which is a common waste product from biodiesel industry, to improve the cost-effectiveness of carotenoids production. In conclusion, this system can serve as a biorefinery for both biofuel and value-added metabolites production
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