High Cell Density Fermentation Strategy for High-Level Soluble Expression of Glucagon-like Peptide-1 Analogue in Escherichia coli

Glucagon-like peptide-1 (GLP-1) is an incretin hormone and therapeutic agent for Type II diabetes mellitus. However, recombinant production in E. coli yields insufficient quantities, increasing manufacturing costs and limiting patient access. Improving yield and productivity is crucial to make GLP-1 treatments more affordable. An optimized bioprocess was developed to enhance the yield of recombinant GLP-1 (rGLP-1) analogues. Expression constructs encoding monomeric and concatemeric GLP-1 fused to GST were designed. Batch fermentations of these clones at varying pre-induction specific growth rates guided the fed-batch strategy for yield enhancement. The specific yield of monomer construct exhibited higher yields than the concatemer. Process optimization achieved a specific yield (Yp/x) of 116.7 mg/g, a dry cell weight of 88.9 g/L, and a volumetric yield of 10.3 g/L. The specific productivity of soluble rGLP-1 reached 0.4 g/L/h. Purification via affinity chromatography and enterokinase cleavage yielded authentic GLP-1 peptide confirmed by Western blot and mass spectrometry. The developed high-yield fermentation process significantly enhances rGLP-1 productivity in E. coli, potentially reducing upstream production costs by 20–30% and enabling wider accessibility to affordable GLP-1 therapies.