Types segmentation focuses on expression systems, including E. coli, Mammalian Cells, Yeast, and Other Expression Systems. E. coli (40% market share) is preferred for cost-efficient recombinant protein production, particularly in academic and small-scale biopharma applications. Mammalian Cells (35%) dominate complex protein purification, such as post-translationally modified biologics, due to their eukaryotic machinery. Yeast (15%) balances cost and functionality for simpler proteins. Other systems (10%) include insect, fungal, or plant-based platforms, addressing niche applications. This segmentation underscores technological diversity: E. coliโs scalability vs. mammalian cellsโ bioactivity fidelity. Each systemโs adoption correlates with target protein complexity and regulatory requirements, defining the Protein Expression and Purification Services market structure.