Biosynthesis of di-rhamnolipids and variations of congeners composition in genetically-engineered Escherichia coli
To engineer Escherichia coli for the heterologous production of di-rhamnolipids, which are important biosurfactants but mainly produced by opportunistic pathogen Pseudomonas aeruginosa.
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.
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.
KeywordsDi-rhamnolipids congeners Escherichia coli Fatty acids synthesis Rhamnolipids Rhamnose synthesis
This work was supported by the National Natural Science Foundation of China (Foundation for Young Scholars: 21406042), and Public Science and Technology Research Funds Projects of Ocean (201505032). We also acknowledge Prof. Yingjin Yuan (Tianjin University) for supplying the vectors YX210, YX211, YX213 and YX214.
Supplementary Table 1—Strains and plasmids used in this study.
Supplementary Table 2—Primers used in this study.
Supplementary Table 3—Sequences of codon-optimized genes.
Supplementary Table 4—Rhamnolipids production and yield in engineered E. coli strains.
Supplementary Figure 1—Plasmids diagram of DJ202 and DJ204.
Supplementary Figure 2—Base peak ion intensity chromatograms and mass spectrometry (MS) data of engineered E. coli strains.
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