title: Biosynthesis of di-rhamnolipids and variations of congeners composition in genetically-engineered Escherichia coli.
abstract: OBJECTIVE
  To engineer Escherichia coli for the heterologous production of di-rhamnolipids, which are important biosurfactants but mainly produced by opportunistic pathogen Pseudomonas aeruginosa.
  
  
  RESULTS
  The codon-optimized rhlAB and rhlC genes originating from P. aeruginosa and Burkholderia pseudomallei were combinatorially expressed in E. coli to produce di-rhamnolipids with varied congeners compositions. Genes involved in endogenous upstream pathways (rhamnose and fatty acids synthesis) were co-overexpressed with rhlAB-rhlC, resulting in variations of rhamnolipids production and congeners compositions. Under the shake-flask condition, co-overexpression of rfbD with rhlAB-rhlC increased rhamnolipids production (0.64 ± 0.02 g l-1) than that in strain only expressing rhlAB-rhlC (0.446 ± 0.009 g l-1), which was mainly composed of di-rhamnolipids congeners Rha-Rha-C10-C10.
  
  
  CONCLUSIONS
  Biosynthesis of di-rhamnolipids and variations of congeners composition in genetically engineered E. coli strains were achieved via combiniations of mono-/di-rhamnolipids synthesis modules and endogenous upstream modules.
authors.affiliation: The Institute of Seawater Desalination and Multipurpose Utilization, SOA, Tianjin, 300192, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Du
authors.affiliation: The Institute of Seawater Desalination and Multipurpose Utilization, SOA, Tianjin, 300192, China.
authors.forename: Aijun
authors.initials: A
authors.lastname: Zhang
authors.affiliation: The Institute of Seawater Desalination and Multipurpose Utilization, SOA, Tianjin, 300192, China.
authors.forename: Jian'an
authors.initials: J
authors.lastname: Hao
authors.affiliation: The Institute of Seawater Desalination and Multipurpose Utilization, SOA, Tianjin, 300192, China. 13820529296@163.com.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D016957:Burkholderia pseudomallei / Q000201:enzymology / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D015870:Gene Expression; D006017:Glycolipids / Q000096:biosynthesis*; D060847:Metabolic Engineering; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D011550:Pseudomonas aeruginosa / Q000201:enzymology / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D006017:Glycolipids; D011994:Recombinant Proteins; C051310:rhamnolipid hemolysin, Pseudomonas aeruginosa
keywords: Di-rhamnolipids congeners; Escherichia coli; Fatty acids synthesis; Rhamnolipids; Rhamnose synthesis