Expression of the Genes Encoding Ectoine Synthases from Cobetia marina CICC10367 in E. coli BL21

In order to investigate the effects of the concentration of NaCl, the medium components and the recombinant type on the expression of the ectoine synthase genes ectABC in Escherichia coli BL21, ectABC and their promotor sequence from Cobetia marina CICC10367 were cloned. The cloned sequence was restructured with expression vector pET43.1 and then the recombinant vector was transformed into E. coli BL21. Two types of recombinant were obtained including recombinant ect03, the restructured ectABC and recombinant pect21, the restructured ectABC with promotor. The expression products of these two recombinants were identified by 1H-NMR and the effect of induction method and condition on the expression of ectoine was investigated. The result indicated that low concentration of NaCl was conducive to the expression of ectoine in recombinant ect03. The highest concentration of ectoine from recombinant ect03 was 216.1 g/L in MMG medium under 0.5% NaCl. The use of monosodium glutamate improved the expression of ectoine significantly. Higher concentration of NaCl (3%) was conducive to the expression of ectoine in recombinant pect21.