title: [Construction and optimization of Escherichia coli for producing rhamnolipid biosurfactant].
abstract: Rhamnolipid biosurfactant is mainly produced by Pseudomonas aeruginosa that is the opportunistic pathogenic strain and not suitable for future industrial development. In order to develop a relatively safe microbial strain for the production of rhamnolipid biosurfactant, we constructed engineered Escherichia coli strains for rhamnolipid production by expressing different copy numbers of rhamnosyltransferase (rhlAB) gene with the constitutive synthetic promoters of different strengths in E. coli ATCC 8739. We further studied the combinatorial regulation of rhlAB gene and rhaBDAC gene cluster for dTDP-1-rhamnose biosynthesis with different synthetic promoters, and obtained the best engineered strain-E. coli TIB-RAB226. Through the optimization of culture temperature, the titer of rhamnolipd reached 124.3 mg/L, 1.17 fold higher than that under the original condition. Fed-batch fermentation further improved the production of rhamnolipid and the titer reached the highest 209.2 mg/L within 12 h. High performance liquid chromatography-mass spectrometry (LC-MS) analysis showed that there are total 5 mono-rhamnolipid congeners with different nuclear mass ratio and relative abundance. This study laid foundation for heterologous biosynthesis of rhanomilipd.
authors.forename: Zhijin
authors.initials: Z
authors.lastname: Gong
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Peng
authors.forename: Yuting
authors.initials: Y
authors.lastname: Zhang
authors.forename: Guotian
authors.initials: G
authors.lastname: Song
authors.forename: Wujiu
authors.initials: W
authors.lastname: Chen
authors.forename: Shiru
authors.initials: S
authors.lastname: Jia
authors.forename: Qinhong
authors.initials: Q
authors.lastname: Wang
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D061249:Batch Cell Culture Techniques; D003651:Decanoates; D004926:Escherichia coli / Q000378:metabolism*; D005285:Fermentation; D006017:Glycolipids / Q000096:biosynthesis*; D006602:Hexosyltransferases / Q000235:genetics; D007218:Industrial Microbiology / Q000379:methods*; D005810:Multigene Family; D011401:Promoter Regions, Genetic; D011550:Pseudomonas aeruginosa; D012210:Rhamnose / Q000031:analogs & derivatives / Q000096:biosynthesis; D013501:Surface-Active Agents / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D003651:Decanoates; D006017:Glycolipids; D013501:Surface-Active Agents; C418382:rhamnolipid; C085734:rhamnopyranosyl-3-hydroxydecanoyl-3-hydroxydecanoate; D006602:Hexosyltransferases; D012210:Rhamnose