P124: Enhanced zeaxanthin production from metabolically engineered Escherichia coli harboring exogenous mevalonate pathway

Carotenoids are C40 isoprenoids which consist of eight isoprene units and can be divided in two major groups of carotenes and xanthophylls. Xanthophylls are oxygenated derivatives of carotenes with epoxy, keto or hydroxyl groups. Zeaxanthin (β,β-carotene-3,3'-diol) is the most common xanthopyll (carotenoid alcohol) found in nature. It is the yellow pigment that gives corn, saffron, and many other plants their characteristic color, and moreover, is found in some bacteria including Pantoea agglomerans and Pantoea ananatis. Carotenoids including zeaxanthin are derived from IPP and DMAPP which are building blocks of isoprenoids. Generally, IPP and DMAPP are synthesized from methyl erythritol phosphate (MEP) or mevalonate (MVA) pathway. We have produced the precursors of zeaxanthin, lycopene and β-carotene, using recombinant Escherichia coli harboring heterologous combinatorial MVA pathway. β-Carotene is converted to zeaxanthin by hydroxylase via β-cryptoxanthin (β,β-carotene-3-ol). The crtZ genes encoding β-carotene hydroxylases were amplified from Pantoea agglomerans and Pantoea ananatis, and introduced to the β-carotene producing E. coli for zeaxanthin production. We successfully produced high amount of zeaxanthin using the recombinant E. coli.

This work was supported by the Intelligent Synthetic Biology Center of Global Frontier Project funded by the MEST (2011-0031964), a grant from the Next-Generation BioGreen 21 Program (SSAC PJ0081842012), Rural Development Administration, and a BK21 Program of Korea.