Autoinduction expression of Bst DNA polymerase using lac operon-controlled expression systems in Escherichia coli

Abstract

Autoinduction simplified the steps for protein production by omitting the need to monitor the correct time for addition of inducer. This method is preferable for industrially production of protein. By using lac operon-controlled expression system, it is possible to produce the protein without the addition of IPTG as inducer. In a conventional way, IPTG was added at the exponential growth phase. By using autoinduction, IPTG could be replaced by lactose in the lac operon-controlled expression systems. Lactose was already supplemented in the medium and it was more cost efficient than IPTG. Therefore, this study aims to employ autoinduction method for expression of our protein target as it is a more convenient way and it is suitable for industrial application. In this study, DNA polymerase from Geobacillus stearothermophilus (Bst DNA polymerase), an enzyme which generally used in loop-mediated isothermal amplification (LAMP) assay, was expressed using lac operon-controlled expression systems in Escherichia coli. Bst DNA polymerase was successfully expressed using autoinduction expression method in LB medium containing 0.2% Lactose.