3'-Sialyllactose (3'-SL) is a pivotal acidic human milk oligosaccharide (HMO) that plays an indispensable role in neonatal brain development, immune system priming, and gut health. Composed of a sialic acid (N-acetylneuraminic acid) molecule linked to the galactose unit of lactose via a ɑ-2,3-glycosidic bond, 3'-SL is more than just a nutrient; it is a bioactive signaling molecule. Unlike neutral HMOs, the sialylated nature of 3'-SL provides specific anti-inflammatory and neuroprotective benefits, particularly in the protection against necrotizing enterocolitis (NEC). CD BioGlyco provides an industry-leading 3'-SL production service within our Synthetic Glycobiology division. By bypassing the high costs and ethical concerns of mammalian milk extraction, we utilize precision-engineered microbial factories to deliver human-identical 3'-SL with unmatched purity and scalability for global research and commercialization.
Core Technologies
CD BioGlyco integrates advanced synthetic biology tools to optimize the biosynthesis of acidic glycans:
Sialyltransferase (ST) Engineering
We utilize a library of high-activity ɑ-2,3-sialyltransferases (e.g., from Neisseria meningitidis or Pasteurella multocida) engineered for superior regiospecificity and substrate affinity.
CMP-Neu5Ac Regeneration Systems
To drive the reaction forward, we implement a multi-enzyme cycle (NeuA, NeuB, NeuC) that regenerates the high-energy donor CMP-sialic acid in situ from low-cost precursors.
Chassis Refactoring
Our E. coli and B. subtilis hosts are engineered to be deficient in sialic acid aldolases and sialidases, preventing the degradation of the target 3'-SL product.
Membrane Permeability Optimization
We modulate the expression of lactose permeases (LacY) and sialic acid transporters to maintain optimal intracellular concentrations for maximum biocatalytic efficiency.
Nurturing Innovation through Sialylated Glycobiology: Your Partner in Bio-Identical HMO Excellence.
The 3'-SL production service at CD BioGlyco is a cornerstone of our comprehensive synthetic glycobiology platform. Our scope covers the entire development cycle, providing a seamless transition for clients from early-stage discovery to market-ready production. We offer custom strain development, where we refactor microbial hosts to utilize specific carbon sources, reducing overall production costs. Our process engineering service focuses on maximizing the space-time yield of 3'-SL, ensuring that our clients receive a product that is not only high in purity but also economically viable for large-scale applications.
In addition to manufacturing, we provide analytical support and regulatory documentation, including detailed impurity profiles and safety data required for Novel Food filings. We offer stable isotope labeling (13C/15N) for 3'-SL, which is critical for pharmacokinetic studies in clinical research. Our service also includes formula development consultation, assisting clients in the complex integration of 3'-SL with other neutral HMOs like 2'-FL to create optimized, human-milk-mimetic blends. Whether you are a pharmaceutical firm developing gut-brain axis therapeutics or a nutritional company enhancing infant formula, our service scope is designed to provide the technical depth and industrial reliability your project demands.
Workflow
1. Pathway Integration & Host Selection
We initiate the process by selecting the most suitable microbial host, prioritizing strains with a generally recognized as safe (GRAS) certification and a proven history in industrial fermentation, such as specific derivatives of E. coli or Saccharomyces cerevisiae. The core sialylation biosynthetic module, encompassing genes for CMP-sialic acid synthesis (e.g., neuA, neuB, neuC) and the specific α-2,3-sialyltransferase, is designed in silico for optimal codon usage and expression. This module is then stably and precisely integrated into a neutral site of the host genome using high-efficiency, markerless CRISPR/Cas9 genome editing. This technique ensures seamless insertion without leaving antibiotic resistance genes or other selectable markers, resulting in a genetically stable production strain suitable for food and pharmaceutical applications.
2. Flux Balancing:
To achieve high-yield sialyllactose production, we employ a dynamic, data-driven approach to balance the intracellular supply of the activated sugar donor (CMP-sialic acid) with the consumption capacity of the sialyltransferase. This involves real-time metabolic monitoring through techniques like intracellular metabolomics and enzyme activity assays. Based on this data, we fine-tune the expression levels of the donor-synthesis operon and the transferase gene using tunable promoters and ribosomal binding sites. The primary objective is to create a matched flux, thereby preventing the wasteful accumulation or depletion of key intermediates like CMP-sialic acid or sialic acid, which can be toxic or lead to metabolic inefficiency and by-product formation.
3. Optimization of Fermentation Parameters:
We leverage parallel high-throughput microbioreactor systems (scaled down to 2L) to rapidly and systematically explore the multidimensional fermentation parameter space. Using design of experiments (DoE) methodologies, we screen and identify the optimal combination of critical process variables. These include the precise temperature and pH setpoints that maximize both cell growth and sialyltransferase activity, as well as the feeding strategy for key substrates. The timing, rate, and ratio of lactose (acceptor) and precursor molecules for sialic acid biosynthesis are optimized to ensure continuous, high-rate product formation while avoiding substrate inhibition or catabolite repression.
4. Scaling to Industrial Titer
Once optimal conditions are established at the bench scale, the validated strain and process are transferred to our pilot-scale and subsequently large-scale fermentation suites. The core strategy is a high-cell-density fed-batch process, meticulously scaled by maintaining constant critical parameters such as oxygen transfer rate (kLa), mixing time, and specific substrate uptake rates. Advanced process control algorithms dynamically adjust the feed rates of carbon, nitrogen, and specific precursors to sustain a prolonged production phase, driving the titer of sialyllactose to industrially and economically relevant concentrations, typically targeting tens of grams per liter.
5. Refined Downstream Purification:
The harvested fermentation broth is processed through a proprietary, sequential purification platform designed to isolate high-purity sialyllactose. The initial steps involve clarification and decolorization using activated carbon or specific adsorbents to remove pigments and media components. This is followed by deionization via ion-exchange chromatography to strip away salts and charged impurities. A critical polishing step employs tailored nanofiltration membranes to concentrate the product and remove low molecular weight contaminants, residual monosaccharides, and salts. The final product is recovered either as a highly pure crystalline solid through controlled crystallization or as a fine powder via spray-drying.
6. Structural Integrity Validation:
Every production batch is subjected to a rigorous, multi-layered analytical quality control protocol. High-performance liquid chromatography (HPLC) with appropriate detectors is used for quantitative purity assessment, ensuring levels exceed 98%. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) provides exact mass confirmation and screens for trace contaminants. The definitive proof of structure and linkage specificity is obtained through proton nuclear magnetic resonance (1H-NMR) spectroscopy, which confirms the characteristic anomeric proton signal of the α-2,3-glycosidic bond. Additionally, assays are performed to guarantee the absence of residual host cell proteins (HCP), DNA (HC-DNA), and endotoxins, ensuring product safety and compliance.
Publication Data
Journal: Processes
DOI: org/10.3390/pr9060932
IF: 2.8
Published: 2021
Results: In this study, the authors developed an efficient one-pot biosynthesis system for producing 3′-SL, a significant human milk oligosaccharide, using a single whole-cell approach. They engineered an E. coli strain to co-express four key enzymes, CMP-sialic acid synthetase (CSS), α-2,3-sialyltransferase (ST), CMP kinase (CMK), and polyphosphate kinase (PPK), through compatible plasmids, creating an integrated catalytic pathway for 3′-SL generation and CTP regeneration. The researchers optimized critical parameters, including temperature (35°C), pH (7.0), and concentrations of cell extracts, polyphosphate, CMP, and MgCl2, while also enhancing cell permeability with Triton X-100. Under these conditions, the system achieved high yields of 53.0 mM in a 25 mL scale and 52.8 mM in a 4 L scale, with substrate conversion rates exceeding 97%. This multi-enzyme cascade demonstrates a simplified, scalable, and economically viable process for 3′-SL production, highlighting its potential for industrial applications.
Application
Necrotizing Enterocolitis (NEC) Prevention
3'-SL has been shown in clinical models to reduce the incidence and severity of NEC by modulating intestinal epithelial cell signaling.
Pathogen Decoy Therapy
Acts as a receptor analogue that binds to sialic-acid-recognizing pathogens, such as certain strains of Salmonella and influenza viruses, preventing their attachment to host cells.
Immune System Priming
3'-SL interacts with immune cells in the gut-associated lymphoid tissue (GALT), promoting the maturation of the immune system and reducing the risk of allergies.
Microbiome Engineering
Used to selectively stimulate the growth of beneficial Bifidobacterium species that possess specific sialidase enzymes, enhancing gut microbial diversity.
Advantages
High Regiospecificity
Our engineered sialyltransferases provide exclusive α-2,3 linkages, ensuring your 3'-SL is structurally distinct from 6'-SL and identical to its natural counterpart.
Donor Sugar Recycling
Our proprietary metabolic loops regenerate CMP-Neu5Ac efficiently, significantly lowering the cost of production compared to enzymatic synthesis using expensive substrates
Rapid Scale-Up Capability
Our modular fermentation infrastructure allows for a quick transition from lab-scale pilot runs to multi-ton production batches.
Comprehensive Analytical Data
Every batch is accompanied by 1H-NMR and LC-MS spectra, providing definitive proof of structural identity and chemical purity.
Frequently Asked Questions
Customer Review
"The 3'-SL provided by CD BioGlyco exhibited exceptional purity. It was the only product that gave us consistent results in our receptor-binding assays."
– Dr. L.V., Senior Scientist, Neonatal Health
"We were impressed with the analytical documentation provided. The NMR data gave us the confidence we needed regarding the ɑ-2,3 linkage specificity."
– Dr. A.M., Principal Investigator, Neuroscience
"We've tried various sources for 3'-SL, but CD BioGlyco's biosynthetic material is consistently the most reliable and cost-effective for our microbiome studies."
– Dr. S.B., Associate Professor, Microbiology
Associated Services
Ascorbyl Glucoside Production Service
High-stability Vitamin C derivatives for health and beauty applications.
Acetyl Chitosamine Production Service
Specialized synthesis for dietary and tissue engineering research.
Trehalose Production Service
Production of protective disaccharides for protein stabilization and food safety.
CD BioGlyco is a world-class leader in the synthetic glycobiology space, offering specialized 3'-SL production services. By combining advanced enzyme engineering with industrial fermentation, we provide a reliable, sustainable, and high-purity supply of this essential milk oligosaccharide. Whether for infant nutrition or therapeutic research, CD BioGlyco is your partner in engineering the future of human health. To learn more about our 3'-SL production capabilities or to discuss a custom project with our scientific experts, please contact us today.
Reference
Li, Z.; et al. Efficient production of 3'-sialyllactose by single whole-cell in one-pot biosynthesis. Processes. 2021, 9(6): 932. (Open Access)
For research use only. Not intended for any clinical use.
