Simple approach for expression and rapid purification of Taq DNA polymerase in three Escherichia coli strains

Background and objectives: One of the most commonly employed bacterial hosts for the synthesis of recombinant proteins is Escherichia coli (E. coli). Choosing an ideal host for the production of the protein of interest is an important step in the large-scale production process. Due to its thermostable characteristic, Taq Pol I, which was first isolated from the bacterium Thermus aquaticus (Taq), is now a typical enzyme found in many laboratories. This study aimed to identify the ideal host for large-scale production of Taq Pol I and purify the enzyme under a simple and rapid purification method. Methods: Taq Pol I gene in pSE420 plasmid was overexpressed in E. coli strains DH5α, TOP10 and BL21(DE3) pLysS. The enzyme was purified using Pluthero’s method and dialyzed using Amicon® Ultra-4 Centrifugal Filter. Results: The host strain E. coli TOP10 produced the highest amounts of Taq Pol I, followed by DH5α and BL21(DE3) pLysS. An estimated 4.5 U/μL of Taq Pol I was produced from a 200 mL culture of TOP10 host. Conclusion: This study provides data on the capacity of the E. coli strains used for Taq Pol I protein production. This information can be used to accelerate future targeted strain selection for the production of a specific protein of interest.