Clean synthesis of isoprene with six E. coli engineering strains

Abstract

Isoprene is one of the most important platform chemicals containing conjugated double bonds and utilized as the precursor material of varieties of chemical raw materials. Currently, isoprene is mostly produced by petroleum smelting, which produces CO2 and some pollution. In that case, the clean production method of isoprene is still the focus of current research. Isoprene synthase (IspS) catalyzes isoprene formation from a metabolic intermediate DMAPP. The expression level and enzyme activity of IspS from different strains affect the amount of isoprene production. In this study, six IspS protein sequences were obtained by searching literatures and NCBI database based on the phylogenetic analysis. We analysed the conservation of their catalytic structures and constructed pBAD expression frameworks for them. The isoprene synthesis systems in E. coli were built and worked in the best induction condition predicted in our study. We used toluene to collect the isoprene produced in the system detected and compared the productivity of each strain. Our results show that the production in cells were 1.55-5.51 μg/L/h.