Expression of the Extracellular Levansucrase and Invertase Genes from Zymomonas mobilis in Escherichia coli Cells

We investigated the expression and localization in Escherichia coli of sucZE2 and sucZE3, encoding Zymomonas mobilis extracellular levansucrase and invertase, respectively, and lacking a typical N-terminal secretion signal. Levansucrase and invertase were expressed efficiently under the lac and tac promoters in E. coli cells, and some of the levansucrase produced was localized in the periplasmic space. The sucZE2 expression was not lethal to E. coli in the presence of 5% sucrose, and led to the accumulation of levan from sucrose.