title: Metabolic engineering of Rhodopseudomonas palustris for squalene production.
abstract: Squalene is a strong antioxidant used extensively in the food, cosmetic and medicine industries. Rhodopseudomonas palustris TIE-1 was used as the host because of its ability to grow photosynthetically using solar energy and carbon dioxide from atmosphere. The deletion of the shc gene resulted in a squalene production of 3.8 mg/g DCW, which was 27-times higher than that in the wild type strain. For constructing a substrate channel to elevate the conversion efficiency, we tried to fuse crtE gene with hpnD gene. By fusing the two genes, squalene content was increased to 12.6 mg/g DCW, which was 27.4 % higher than that resulted from the co-expression method. At last, the titer of squalene reached 15.8 mg/g DCW by co-expressing the dxs gene, corresponding to 112-fold increase relative to that for wild-type strain. This study provided novel strategies for improving squalene yield and demonstrated the potential of producing squalene by Rhodopseudomonas palustris.
authors.affiliation: Department of Pathogen Biology, School of Basic Medical Science, Xi'an Medical University, Xi'an, 710021, Shaanxi, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Xu
authors.affiliation: Department of Pathogen Biology, School of Basic Medical Science, Xi'an Medical University, Xi'an, 710021, Shaanxi, China.
authors.forename: Changbin
authors.initials: C
authors.lastname: Chai
authors.affiliation: Department of Pathogen Biology, School of Basic Medical Science, Xi'an Medical University, Xi'an, 710021, Shaanxi, China.
authors.forename: Lingqiao
authors.initials: L
authors.lastname: Shao
authors.affiliation: Department of Pathogen Biology, School of Basic Medical Science, Xi'an Medical University, Xi'an, 710021, Shaanxi, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Yao
authors.affiliation: Department of Pathogen Biology, School of Basic Medical Science, Xi'an Medical University, Xi'an, 710021, Shaanxi, China. yang.wang@xiyi.edu.cn.
authors.forename: Yang
authors.identifier: http://orcid.org/0000-0002-0984-6956
authors.initials: Y
authors.lastname: Wang
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism; D017353:Gene Deletion; D005798:Genes, Bacterial / Q000235:genetics; D060847:Metabolic Engineering; D010788:Photosynthesis; D012241:Rhodopseudomonas / Q000235:genetics* / Q000378:metabolism*; D013185:Squalene / Q000378:metabolism*
chemical_list: D002245:Carbon Dioxide; D013185:Squalene
keywords: Fusion expression; Rhodopseudomonas palustris; Squalene; Squalene-hopene cyclase