Part:BBa_K3331009
B.S galU+B.S pgmA
The yield of EPS can be significantly increased by overexpressing two key enzymes galU and pgmA at the same time. Reference：Levander Fredrik et al. Applied and environmental microbiology,2002,68(2).
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
Overview
In order to increase the production of exopolysaccharides (EPSs), we altered the levels of enzymes in the central metabolism. We selected and overexpressed two key enzymes, galU and pgmA at the same time. And we found we successfully enhance the production of EPSs in E.coli.DH5α
Characterization
The test plasmid was constructed by Golden Gate Assembly and was confirmed by colony PCR. The length of the B.S galU fragment is 951bp, and the length of B.S pgmA is 1875bp. The following results showed successful constructions.
Our strain was cultured in ampicillin-resistant LB medium with strictly control variables. We stop the culture after 24 hours of culture. We measure the expression of EPS and the level of gene transcription during this period. RT-qPCR was conducted to test their expressions. And we can see these two genes were transcribed successfully.
Anthrone sulfuric acid method was used to detect EPS yields. Compared with the blank strain, the EPS yield of the engineering strain increased by 29%. The results of this study clearly show that it is possible to enhance the production of EPSs in DH5α by altering the expression of B.S. pgmA and B.S. galU.
We also measured the growth of DH5α transferred into the plasmid by enzyme labeling instrument. We measure the OD value of bacteria every hour under the wavelength of 600nm and fit the results. It was compared with the blankDH5α and the growth curve was drawn.
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