Background

As health management becomes a national priority, obesity and diabetes have emerged as "silent killers" threatening public health. According to data from the World Health Organization, more than 2 billion people worldwide suffer from overweight or obesity, with China’s adult obesity rate approaching 10%. Meanwhile, diabetes cases are equally alarming, with over 140 million patients in China alone. Since obesity often leads to metabolic disorders, the combination of "healthy weight loss + blood glucose management" has become an essential public demand.

Semaglutide

Against this backdrop, Semaglutide (also known as Somaglutide, a long-acting glucagon-like peptide-1 receptor [GLP-1R] agonist) has risen to prominence for its weight-loss and glucose-lowering benefits, with market demand soaring. In 2024, its global sales demonstrated strong momentum, and by Q1 2025, it even surpassed Keytruda (Pembrolizumab) to become the world’s best-selling drug.

Traditional chemical synthesis involves multiple steps with low recovery rates, leading to high costs and long production cycles. By contrast, novel biosynthetic methods employ prokaryotic or eukaryotic expression systems to ferment and synthesize the main peptide chain. The precursor peptide is extracted and purified from the fermentation broth, the solubility-enhancing tag is enzymatically cleaved, and the N-terminal amino acid (including non-proteinogenic amino acids) is conjugated, ultimately yielding Semaglutide.

Meanwhile, peptide-based drugs—thanks to their high activity, low toxicity, and strong specificity—are increasingly favored for treating diabetes, cancer, autoimmune diseases, and more. The construction of peptide biosynthesis fermentation systems, along with strict control of host cell DNA (HCD) and host cell protein (HCP) residues, directly determines the safety and efficacy of peptide products.

Biosynthesis: E. coli Fermentation Process

• Gene Design & Vector Construction

• Based on the target peptide’s amino acid sequence, codon optimization enhances expression efficiency. The synthesized gene fragment is inserted into an expression vector (e.g., pET system plasmid), equipped with a strong promoter (e.g., T7 lac), antibiotic resistance marker, and replication origin.

• Engineered Strain Cultivation & Induced Expression

• The recombinant plasmid is introduced into E. coli host cells (e.g., BL21(DE3) strain). High-density fermentation is carried out in bioreactors with temperature and pH monitored and optimized via fermentation kinetics models. Once cell density reaches a critical level, IPTG induction or temperature shift triggers target peptide expression.

• Harvesting & Cell Lysis/Clarification

• Induced cells are harvested by centrifugation, followed by mechanical disruption (high-pressure homogenization) or chemical lysis (alkaline treatment) to release intracellular components. Fermentation broth undergoes continuous-flow centrifugation at 4–10 °C to separate biomass, yielding wet cell paste. The paste is resuspended in cold buffer containing protease inhibitors and lysed under controlled temperature. Lysates are clarified via centrifugation and depth filtration, generating crude extract for downstream purification.

• Extraction & Purification

• Ultrafiltration membranes remove macromolecular impurities while retaining target proteins. Affinity chromatography enables highly selective separation by specific ligand-peptide binding. The purification process typically involves centrifugation, filtration, and chromatography to eliminate impurities and byproducts.

HCD/HCP Residual Risk & Testing Necessity

Target peptides in fermentation lysates coexist with impurities such as host proteins, host nucleic acids, and endotoxins. The mainstream purification strategy includes three-step chromatography (affinity – ion exchange – size exclusion).

• HCD (host cell DNA) consists of DNA fragments derived from E. coli cells. Its biosafety risks include carcinogenicity, infectivity, and immunogenic reactions.

• HCP (host cell proteins) are highly complex, with more than 2,000 proteins potentially present in an E. coli lysate. Their biosafety risks include protease-mediated degradation of therapeutic proteins and immunogenic reactions.

To ensure product safety, regulatory agencies have established strict limits on residual E. coli HCD and HCP levels.

Hzymes Biotech Peptide Product Portfolio

01.  Biosynthetic GLP-1 29 Peptide

Hzymes independently develops and manufactures GLP-1 (29 amino acids), expressed recombinantly in E. coli. Following enzymatic cleavage, chromatography purification, and lyophilization, a freeze-dried powder is obtained. Compared to chemical synthesis, this approach enables large-scale continuous production with high purity, low impurities, high yield, and reduced cost.

02. Recombinant Enterokinase (High Specificity)

Recombinant enterokinase (rEK) is produced via genetic engineering, offering high purity, activity, and specificity. It recognizes and cleaves proteins containing the Asp-Asp-Asp-Asp-Lys (DDDDK) motif.

• Applications:
• Fusion protein processing in genetic engineering: removes N-terminal tags to ensure proper folding and functionality.
• Peptide drug manufacturing: processes insulin, its analogs, GLP-1, and others by removing N-terminal tags while preserving bioactivity.

03.  E. coli HCD Detection

Hzymes’ E. coli residual DNA detection kit adopts qPCR probe-based technology, combined with automated nucleic acid extraction systems for high-throughput applications. It provides accurate and efficient HCD detection solutions, suitable for quality control at various peptide production stages.

04. E. coli HCP Detection

Enzyme-linked immunosorbent assay (ELISA) remains the most widely used method for HCP detection. The Chinese Pharmacopoeia recommends ELISA for host protein analysis, while the USP <1132> chapter also highlights ELISA as the preferred method.

Hzymes’ E. coli HCP kit uses a double-antibody sandwich one-step format, reducing detection time to just 2 hours, and enables rapid quantitative analysis of HCP content in samples.

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