Fig. 3From: Metabolic engineering for high yield synthesis of astaxanthin in Xanthophyllomyces dendrorhousIntegration of additional copies of crtE and crtS using a Cre/lox-P system [59]. The Cre–loxP recombination system allows selectable markers recycling. Holding the transitory expression of cre (encoding Cre recombinase) controlled by an unstable vector, the selectable marker flanked by loxP sites were removed along with the Cre vectorBack to article page