Related Experiment Video
Updated: Aug 6, 2026
10:17
Analysis of Fucosylated Human Milk Trisaccharides in Biotechnological Context Using Genetically Encoded Biosensors
Published on: April 13, 2019
Plasmid- and Inducer-Free Biosynthesis of Difucosyllactose through Rational Fusion Enzyme Engineering and Systematic
Zhiqiang Liu1,2, Binglin Li1,2, Jieying Deng1,2
1Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
ACS Synthetic Biology
|July 18, 2026
Summary
Researchers developed a novel, plasmid- and inducer-free Escherichia coli strain for efficient difucosyllactose (DFL) production. This engineered strain significantly enhances DFL biosynthesis while minimizing intermediate accumulation, paving the way for cost-effective industrial applications.
Area of Science:
- Biotechnology and Metabolic Engineering
- Microbial Synthesis of Human Milk Oligosaccharides
Background:
- Difucosyllactose (DFL), a fucosylated human milk oligosaccharide, has significant industrial potential.
- Current microbial DFL production is hindered by intermediate (2'-FL) accumulation and high costs from antibiotics/inducers.
Purpose of the Study:
- To engineer a plasmid- and inducer-free Escherichia coli strain for enhanced DFL biosynthesis.
- To minimize 2'-fucosyllactose (2'-FL) accumulation during DFL production.
Main Methods:
- Established the de novo DFL pathway using various α-1,3-fucosyltransferases (α-1,3-FucT).
- Employed combinatorial metabolic engineering and the iMARS framework for enzyme design (FucTaY218K-L60-FutC).
- Engineered a beneficial mutant (FucTaY218K/W31R) and modified the lactose operon for improved growth and production.
Main Results:
- Achieved a DFL titer of 74 g/L with a productivity of 0.96 g/L/h in a 5-L bioreactor.
- Demonstrated the highest reported DFL productivity to date.
- Successfully minimized 2'-FL accumulation through rational enzyme engineering.
Conclusions:
- Developed a robust, environmentally friendly platform for industrial-scale DFL production.
- The study provides a viable strategy for microbial synthesis of other valuable human milk oligosaccharides.
Related Concept Videos
01:22Bioreactor Controls-III
Strain improvement is a foundational strategy in industrial microbiology aimed at maximizing microbial productivity, particularly because natural isolates typically yield commercially valuable products in very low concentrations. Although optimizing the culture medium and environmental conditions can improve yields, these adjustments are inherently limited by the organism’s genetic potential. As a result, the focus shifts toward genetic modifications to enhance biosynthetic capacity. The...
01:30Production of Pharmaceuticals
Industrial insulin production uses genetically engineered E. coli expressing a proinsulin gene controlled by a tryptophan promoter and containing a methionine linker for later cleavage. The cells also carry ampicillin resistance for selective growth. Seed cultures are stored at −80 °C and production begins by thawing a small amount to inoculate starter cultures, which are progressively scaled to a 50,000-L bioreactor. In the bioreactor, E. coli grow in nutrient-rich media under sterile, tightly...
01:25Inducible Operons: lac Operon
The lac operon in Escherichia coli is a model for understanding inducible gene regulation and metabolic flexibility. It integrates local control by lactose and global regulation through catabolite repression, enabling E. coli to preferentially metabolize glucose when available and switch to lactose utilization when glucose is scarce.Structure and Function of the lac OperonThe lac operon contains three structural genes: lacZ (β-galactosidase), lacY (lactose permease), and lacA (thiogalactoside...
01:27Upstream Processing
Upstream processing represents a critical phase in biomanufacturing, wherein biological systems such as microorganisms, mammalian cells, or insect cells are cultivated to produce therapeutic proteins, vaccines, enzymes, or other biologically derived products. This phase encompasses all steps from the selection and genetic manipulation of the production organism to the cultivation of cells in bioreactors under tightly controlled environmental conditions.Host Selection and Genetic OptimizationThe...