Analysis and expression of the carotenoid biosynthesis genes from Deinococcus wulumuqiensis R12 in engineered Escherichia coli

Deinococcus wulumuqiensis R12 is a red-pigmented extremophilic microorganism with powerful antioxidant properties that was isolated from radiation-contaminated soil in Xinjiang Uyghur Autonomous Region of China. The key carotenoid biosynthesis genes, crtE, crtB and crtI, which are related to the cells' antioxidant defense, were identified in the sequenced genome of R12 and analyzed. In order to improve the carotenoid yield in engineered Escherichia coli, the origin of carotenoid biosynthesis genes was discussed, and a strain containing the R12 carotenoid biosynthesis genes was constructed to produce lycopene, an important intermediate in carotenoid metabolism. The gene order and fermentation conditions, including the culture medium, temperature, and light, were optimized to obtain a genetically engineered strain with a high lycopene production capacity. The highest lycopene content was 688 mg L^-1 in strain IEB, which corresponds to a 2.2-fold improvement over the original recombinant strain EBI.