Optimized expression of large fragment DNA polymerase I from in expression system.

DNA polymerase is a DNA polymerase derived from has a strand-displacement activity, and is used in loop-mediated isothermal amplification (LAMP) for rapid detection of COVID-19. Despite its potential to be employed in the detection of COVID-19, using commercially available enzymes is not economically feasible. The use of noncommercial enzyme for routine use is desirable. However, research on DNA polymerase is still limited in Indonesia. For those reasons, a preliminary study of scale-up production of recombinant polymerase was conducted. Therefore, the optimization of expression conditions was performed. The optimum conditions for polymerase expression were as follows: 1 mM of IPTG, post-induction incubation time of 6 h, and induction at OD 1.1. Employing optimum conditions could result in 2.8 times increase in protein yield compared to the initial conditions. Subsequently, an operation in 1 L working volume by a lab-scale bioreactor had been performed, followed by purification and dialysis. The optimum result for a 1 L lab-scale bioreactor was achieved by applying 100 rpm and 3 vvm, giving 11.7 mg/L of protein yield. polymerase was successfully purified showing 813.56 U/mg of polymerase activity.