Genetic code expansion (GCE) represents a pinnacle of translational engineering, allowing for the site-specific incorporation of non-canonical amino acids (ncAAs) into proteins within living cells. At CD BioGlyco, we recognize that the success of GCE is inherently tied to the robustness of the host organism. As an expert synthetic glycobiology specialist, I have seen how traditional expression systems often struggle with the metabolic burden and low fidelity of ncAA incorporation. We are aware of the challenges that traditional expression systems often face in terms of metabolic burden and low fidelity of ncAA incorporation.
Our genetic code expansion service is designed to overcome these hurdles. By engineering specialized chassis strains, we provide a foundation where the translation machinery is optimized for an expanded alphabet. This technology is particularly transformative for glycobiology, enabling the installation of "clickable" handles for precise glycan attachment, the study of site-specific post-translational modifications (PTMs), and the development of next-generation biotherapeutics. Whether you are looking to engineer a microbial factory or a complex eukaryotic system, CD BioGlyco offers the technical sophistication required to redefine the chemical boundaries of your biological products.
Key Technologies
Orthogonal Translation Systems (OTS)
We develop and integrate pairs of engineered aminoacyl-tRNA synthetases (aaRS) and suppressor tRNAs that do not cross-react with the host's endogenous translation machinery. This "orthogonality" is crucial for maintaining high fidelity and preventing the misincorporation of natural amino acids at the intended site.
Genome Refactoring and Codon Reassignment
A significant bottleneck in GCE is the competition with termination factors at stop codons. We utilize advanced genome editing to delete or modify release factors (e.g., RF1) and reassign codons like UAG or UGA exclusively for ncAA incorporation, effectively creating "genomically recoded organisms."
Directed Evolution of aaRS Libraries
Not all ncAAs fit perfectly into natural synthetase pockets. We employ high-throughput positive and negative selection cycles to evolve aaRS variants with superior affinity and specificity for over 200 different ncAAs, ensuring that your chassis is tailored to your specific chemical target.
Revolutionizing Synthetic Glycobiology: Genetic Code Expansion Service
At CD BioGlyco, our service scope is meticulously designed to support every phase of chassis strain development service. We don't just provide a plasmid; we engineer a living platform. Our primary focus is on the systematic modification of host organisms, ranging from Escherichia coli and Saccharomyces cerevisiae to mammalian cell lines, to serve as high-performance chassis for GCE. The implementation of our services begins with a deep analysis of the metabolic flux within the target chassis. Incorporating ncAAs requires a delicate balance between the synthetic pathway of the OTS, the availability of the ncAA (whether exogenously supplied or biosynthetically produced), and the global health of the cell. We provide comprehensive development methods that include:
Host Selection and Adaptation: Identifying the best starting strain based on your final application (e.g., protein yield vs. complex glycosylation needs).
Genomic Integration of OTS: Moving beyond unstable plasmid-based systems to stable, genomically integrated OTS cassettes that ensure long-term expression consistency during scale-up.
Metabolic Rewiring: Engineering uptake transporters to increase the intracellular concentration of ncAAs or developing biosynthetic pathways so the chassis produces the ncAA de novo from simple carbon sources.
Fidelity and Yield Optimization: Fine-tuning the expression levels of the tRNA and aaRS components to minimize the "metabolic burden" and maximize the incorporation efficiency at one or multiple sites.
By situating our GCE services within the broader framework of chassis development, we ensure that the final strain is not only capable of expanded chemistry but is also robust enough for industrial-scale fermentation and production.
Workflow
Project Consultation and Strategy Design
Every project begins with a detailed assessment of the target ncAA and the desired protein product. We determine the optimal codon to be reassigned (e.g., UAG) and select the most appropriate host system.
OTS Screening and Optimization
Using our proprietary library of orthogonal aaRS/tRNA pairs, we identify candidates that show high activity for your specific ncAA. If a perfect match does not exist, we initiate a directed evolution campaign to evolve a bespoke synthetase.
Chassis Engineering and Genome Integration
We utilize gene editing technology to integrate the OTS into the chassis genome. This step often includes the deletion of release factors or the modification of the host's tRNA pool to reduce cross-reactivity.
ncAA Incorporation and Expression Testing
The engineered chassis is tested for its ability to produce the target protein with the ncAA. We utilize reporter systems, such as green fluorescent protein (GFP) variants with internal amber codons, to quantify incorporation efficiency and fidelity.
Multi-omics Validation and Characterization
To ensure the chassis is performing optimally, we conduct transcriptomic and metabolomic profiling. This helps us identify any stress responses triggered by GCE and allows for iterative optimization of the strain's growth and production parameters.
Process Scale-up and Final Delivery
Once the strain is validated at the bench scale, we provide protocols for scale-up in bioreactors. The final deliverable includes the engineered chassis strain, comprehensive characterization data, and optimized cultivation protocols.
Publication Data
DoI: 10.3390/microorganisms13020353
Journal: Microorganisms
IF: 4.2
Published: 2025
Results: This study applies genetic code expansion to control surfactin production in a high cell-density Bacillus subtilis strain (AH2). An amber stop codon was integrated into the surfactin-synthesizing srfA operon, and an orthogonal aminoacyl-tRNA synthetase/tRNA pair from Methanococcus jannaschii was chromosomally inserted to enable site-specific incorporation of the non-canonical amino acid O-methyl-L-tyrosine (OMeY). Without OMeY, no surfactin was produced; with 0.5-1 mM OMeY, shake flasks yielded up to 136 ± 18 mg/L surfactin. In fed-batch bioreactors, feed-associated OMeY addition achieved a maximum surfactin titer of 10.8 g/L, 2.25-fold higher than single OMeY addition. Proteomics revealed OMeY-induced adaptations: increased SrfA proteins, elevated branched-chain amino acid/fatty acid precursor enzymes, reduced motility proteins, and decreased iron acquisition proteins (due to surfactin's chelating ability). This work demonstrates precise, post-transcriptional control of surfactin biosynthesis, advancing microbial cell factory design for bioactive metabolites.
Fig.1 The principle of surfactin biosynthesis based on genetic code expansion. (Hermann, et al., 2025)
Applications
Therapeutic Glycoprotein Engineering
Site-specifically incorporating ncAAs with bio-orthogonal handles allows for the precise, chemical attachment of complex glycans, creating homogeneous glycoforms of monoclonal antibodies or hormones.
Enzyme Evolution and Biocatalysis
By introducing ncAAs with novel chemical groups into the active sites of enzymes, we develop biocatalysts with enhanced thermal stability, broader substrate specificity, or entirely new-to-nature catalytic functions for industrial use.
Site-Specific Bioconjugation
GCE provides the "gold standard" for creating antibody-drug conjugates (ADCs). The ability to place a single reactive handle at a specific residue ensures a defined drug-to-antibody ratio (DAR), improving safety and efficacy.
Biosensor and Biomaterial Development
We develop chassis capable of producing proteins with fluorescent ncAAs or metal-chelating side chains, facilitating the creation of highly sensitive biological sensors and functionalized biopolymers for tissue engineering.
Advantages
Unrivaled Fidelity
Our engineered OTS pairs undergo rigorous negative selection, ensuring that the target site is occupied by the ncAA with >99% purity, virtually eliminating natural amino acid "leakage."
Broad Host Compatibility
CD BioGlyco offers validated GCE chassis across diverse taxa, including specialized bacterial, yeast, and mammalian systems optimized for glycoscience applications.
High-Yield Engineering
We specialize in minimizing the metabolic burden associated with expanded codes, achieving protein yields that are competitive with standard recombinant expression systems.
Stable Genomic Integration
By avoiding plasmid-based expression, our chassis maintain genetic stability over many generations, making them ideal for long-duration industrial fermentation processes.
Frequently Asked Questions
Customer Review
"The team at CD BioGlyco successfully engineered an E. coli chassis for our site-specific labeling project. The fidelity of incorporation was remarkable, and the technical support provided during the scale-up phase was invaluable for our therapeutic pipeline."
– Q.W., Biopharma Firm
"We struggled with low yields using standard GCE kits. CD BioGlyco's genomic integration approach transformed our results, giving us a stable yeast chassis that consistently produces our modified enzymes at industrial titers."
– E.W., Department of Bioengineering
"As a group focusing on glycoengineering, the ability to install clickable handles via GCE has been a game-changer. CD BioGlyco's expertise in both glycobiology and synthetic biology is a rare and powerful combination."
By providing a comprehensive, end-to-end service, from the selection of orthogonal pairs to the delivery of a validated, high-performance chassis, CD BioGlyco empowers researchers to explore chemical spaces that were previously inaccessible. Our commitment to precision, efficiency, and customer success makes us the ideal partner for your next-generation biological project. Please feel free to contact us to provide technical consultation and customized project plans tailored to your specific research.
References
Hermann, A.; et al. Genetic code expansion for controlled surfactin production in a high cell-density Bacillus subtilis strain. Microorganisms. 2025, 13: 353. (Open Access)
For research use only. Not intended for any clinical use.
Fig.1 The principle of surfactin biosynthesis based on genetic code expansion. (Hermann, et al., 2025)
