Optimization of Fermentation Process for Taq DNA Polymerase Production by Recombinant Escherichia coli

Abstract

Taq DNA polymerase is a thermostable enzyme and widely used in PCR technology. In order to improve the production of Taq DNA polymerase by recombinant Escherichia coli, in this study the enzyme yield and specific activity of the enzyme were taken as the inspection indicators. The single factors producing Taq DNA polymerase content were optimized through single factor test: fermentation temperature, pH, amount of IPTG inducer, induction time, and inoculation amount. The results showed that fermentation temperature, pH, concentration of IPTG inducer had a significant impact on the specific enzyme activity of Taq DNA polymerase produced by the genetic engineering strain, while induction culture time and inoculation amount had no significant impact on the specific enzyme activity of Taq DNA polymerase produced by the genetic engineering strain. So fermentation temperature, pH and IPTG inducer concentration were selected as three factors of response surface to optimize the fermentation process of recombinant Escherichia coli for Taq DNA polymerase production. The response surface analysis results showed and that the order of significance for the specific activity of enzymes were: IPTG inducer concentration>fermentation temperature>pH, and the optimal fermentation process parameters were: fermentation temperature 37.2 ℃, pH 7.5, IPTG inducer concentration 0.800 mmol/L. Under this condition, the specific activity of Taq DNA polymerase reached (43.822±0.878) kU/mg.

Keywords

• recombinant escherichia coli
• taq dna polymerase
• specific activity of enzyme
• fermentation process
• response surface methodolog