Heterologous Expression, Purification and Characterization of Fusion-type Pediocin PA-1 in Escherichia coli

Abstract

Pediocin PA-1 is a 4.6 kDa bacteriocin that shows strong antimicrobial activity against some Gram-positive pathogens such as Listeria monocytogenes and Enterococcus faecalis. Due to broad inhibitory spectrum as well as pH and temperature stability, pediocin has a potential application in food preservation as well as in the pharmaceutical industry. For higher manufactory efficiency, pediocin has been expressed in some other heterologous expression systems, mostly on Escherichia coli with different strategies. Here, we show a new strategy to produce pediocin from E. coli BL21(DE3) system as a fusion form by using the expression vector pET43.1a which contains the NusA tag. Our results showed that NusA-fused pediocin almost presented in soluble form with high efficiency (79.8 mg/L obtained by Ni-NTA purification). After removing the fusion tag, recombinant pediocin showed antimicrobial activity against L. monocytogenes ATCC 13932 as 23.5×103 AU/mg of specific activity as well as against E. faecalis, Lactobacillus plantarum and Streptococcus thermophilus. Recombinant pediocin was stable at the wide range of pH (1-12 for 60 min) and high temperature (100oC for 15 min) as well as sensitive to protease treatment as the nature pediocin. These characteristics have opened prospects for applying pediocin as a biological preservative in the food industry.