Activity evaluation of glycolytic promoters from Escherichia coli and application for mevalonate biosynthesis

Promoters are the most important tools to control and regulate gene expression in synthetic biology and metabolic engineering. The expression of target genes in Escherichia coli is usually controlled by inducible promoters which may cause excessive metabolic load on the host and may be uneconomical due to inducer cost. Therefore, it is important to identify more constitutive promoters that are capable of avoiding these limitations. In this study, using the monomeric red fluorescent protein (mRFP) as the reporter gene, ten promoters from the glycolytic pathway of E. coli were cloned and characterized. We found that glycolytic promoters exhibited the advantages of constitutive promoters and higher strength compared with the commonly used inducible promoter Plac. We further introduced glycolytic promoters into the mevalonate biosynthesis system. The maximum mevalonate titer produced by engineered E. coli under the control of glycolytic promoters was obviously higher than that under the control of Plac, indicating the superiority of glycolytic promoter for the metabolic engineering of E. coli. This set of glycolytic promoters significantly expands the range of engineering tools available for E. coli and can be applied in future metabolic engineering studies.