Metabolic Engineering of Escherichia coli for High-Titer Biosynthesis of 3'-Sialyllactose.
J Agric Food Chem
; 72(10): 5379-5390, 2024 Mar 13.
Article
in En
| MEDLINE
| ID: mdl-38420706
ABSTRACT
3'-Sialyllactose (3'-SL) is among the foremost and simplest sialylated breast milk oligosaccharides. In this study, an engineered Escherichia coli for high-titer 3'-SL biosynthesis was developed by introducing a multilevel metabolic engineering strategy, including (1) the introduction of precursor CMP-Neu5Ac synthesis pathway and high-performance α2,3-sialyltransferase (α2,3-SiaT) genes into strain BZ to achieve de novo synthesis of 3'-SL; (2) optimizing the expression of glmS-glmM-glmU involved in the UDP-GlcNAc and CMP-Neu5Ac synthesis pathways, and constructing a glutamine cycle system, balancing the precursor pools; (3) analysis of critical intermediates and inactivation of competitive pathway genes to redirect carbon flux to 3'-SL biosynthesis; and (4) enhanced catalytic performance of rate-limiting enzyme α2,3-SiaT by RBS screening, protein tag cloning. The final strain BZAPKA14 yielded 9.04 g/L 3'-SL in a shake flask. In a 3 L bioreactor, fed-batch fermentation generated 44.2 g/L 3'-SL, with an overall yield and lactose conversion of 0.53 g/(L h) and 0.55 mol 3'-SL/mol, respectively.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Sialic Acids
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Cytidine Monophosphate
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Escherichia coli
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Metabolic Engineering
Limits:
Humans
Language:
En
Journal:
J Agric Food Chem
Year:
2024
Document type:
Article
Affiliation country: