Enhancing expression of recombinant protein LTB of Escherichia coli in competent cells, Escherichia coli BL21 (DE3)

Abstract

The study on improvement of the recombinant protein LTB expression level in E. coli strain
BL21 (DE3) encoding gene eltB of E. coli was conducted. The studied results showed that
TB and YJ media have given the best growth of E. coli BL21 (DE3) in comparison with other
media in the same 2 % initial seed inoculum size (OD600 = 0.8), shaking 200 rpm at 370C for
9 hours. The highest level of fusion protein (6xHis-LTB) was obtained from YJ and HSG media
in the same optimum culture condition (1.2 mM Isopropyl β-D-1-thiogalactopyranoside (IPTG)
for 8 hours at 250C-350C). Molecular weight of purified 6xHis-LTB protein from 6xHis affinity
chromatography was about 35 kDa.