title: Metabolic engineering for synthesis of aryl carotenoids in Rhodococcus.
abstract: Rhodococcus erythropolis naturally synthesizes monocyclic carotenoids: 4-keto-gamma-carotene and gamma-carotene. The genes and the pathway for carotenoid synthesis in R. erythropolis were previously described. We heterologously expressed a beta-carotene desaturase gene (crtU) from Brevibacterium in Rhodococcus to produce aryl carotenoids such as chlorobactene. Expression of the crtU downstream of a chloramphenicol resistance gene on pRhBR171 vector showed higher activity than expression downstream of a native 1-deoxyxylulose-5-phosphate synthase gene (dxs) on pDA71 vector. Expression of the crtU in the beta-carotene ketolase (crtO) knockout Rhodococcus host produced higher purity chlorobactene than expression in the wild-type Rhodococcus host. Growth of the engineered Rhodococcus strain in eight different media showed that nutrient broth yeast extract medium supplemented with fructose gave the highest total yield of chlorobactene. This medium was used for growing the engineered Rhodococcus strain in a 10-l fermentor, and approximately 18 mg of chlorobactene was produced as the almost exclusive carotenoid by fermentation.
authors.affiliation: Biological and Chemical Sciences and Engineering, Central Research and Development, EI DuPont de Nemours Inc., Wilmington, DE 19880-0328, USA.
authors.forename: Luan
authors.initials: L
authors.lastname: Tao
authors.forename: L Winona
authors.initials: LW
authors.lastname: Wagner
authors.forename: Pierre E
authors.initials: PE
authors.lastname: Rouvière
authors.forename: Qiong
authors.initials: Q
authors.lastname: Cheng
mesh_terms: D001709:Biotechnology / Q000379:methods; D001951:Brevibacterium / Q000201:enzymology* / Q000235:genetics; D002338:Carotenoids / Q000096:biosynthesis*; D003470:Culture Media; D044943:Fatty Acid Desaturases / Q000235:genetics / Q000378:metabolism*; D005285:Fermentation; D005818:Genetic Engineering / Q000379:methods*; D012240:Rhodococcus / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D019207:beta Carotene / Q000378:metabolism
chemical_list: D003470:Culture Media; D019207:beta Carotene; C006980:chlorobactene; D002338:Carotenoids; D044943:Fatty Acid Desaturases