Engineering <i>Escherichia coli</i> for the High-Titer Biosynthesis of Lacto-<i>N</i>-tetraose
Miaomiao Hu, Mengli Li, Ming Miao, Tao Zhang
Journal of Agricultural and Food Chemistry
Abstract
Lacto-<i>N</i>-tetraose (LNT), a member of the human milk oligosaccharides family, has received widespread attention because of its importance in infant health. We constructed a whole-cell biotransformation method in <i>Escherichia coli</i> BL21(DE3) for high-titer LNT synthesis. The approach was performed by using a systematic design and metabolic engineering based on the metabolic pathway of LNT. The <i>lgtA</i> (encoding β-1,3-<i>N</i>-acetylglucosaminyltransferase) and <i>wbgO</i> (encoding β-1,3-galactosyltransferase) genes were introduced into the engineered <i>E. coli</i> BL21(DE3) to construct an LNT-producing starting strain B1 (0.22 g/L). Then, the genes related to the LNT metabolic pathway were screened in two vectors to evaluate LNT synthesis. The <i>lgtA</i>-<i>wbgO</i> and <i>galE</i>-<i>galT</i>-<i>galK</i> genes were overexpressed through the two-plasmid system in <i>E. coli</i> BL21(DE3). The titer of LNT (3.42 g/L) had a gain of 14.55 times compared with that of B1. Furthermore, the <i>ugd</i> gene, which was associated with the UDP-Gal bypass pathway, was inactivated to further improve LNT production in shake-flask cultivation (4.14 g/L). The final fed-batch cultivation of the engineered strain produced 31.56 g/L of LNT. This study provided a strategy for the effective production of LNT in <i>E. coli</i>.
Extracted Claims
3 claims extracted from this paper into the knowledge graph
Lacto-N-tetraose (LNT) synthesized in E. coli BL21(DE3)
“The lgtA (encoding β-1,3-N-acetylglucosaminyltransferase) and wbgO (encoding β-1,3-galactosyltransferase) genes were introduced into the engineered E. coli BL21(DE3) to construct an LNT-producing star...”
final fed-batch cultivation produced 31.56 g/L of LNT
“The final fed-batch cultivation of the engineered strain produced 31.56 g/L of LNT.”
LNT production improved by inactivating the ugd gene
“Furthermore, the ugd gene, which was associated with the UDP-Gal bypass pathway, was inactivated to further improve LNT production in shake-flask cultivation (4.14 g/L).”