Development of a Propionibacterium-Escherichia coli Shuttle Vector for Metabolic Engineering of Propionibacterium jensenii, an Efficient Producer of Propionic Acid

Abstract

ABSTRACTPropionic acid (PA) is an important chemical building block and is widely applied for organic synthesis, food, feedstuff, and pharmaceuticals. To date, the strains that can efficiently produce PA have includedPropionibacterium thoenii,P. freudenreichii, andP. acidipropionici. In this report, we show thatP. jenseniiATCC 4868 is also able to produce PA in much higher yields than the previously reported strains. To further improve the production capacity, aP. jensenii-Escherichia colishuttle vector was developed for the metabolic engineering ofP. jensenii. Specifically, a 6.9-kb endogenous plasmid, pZGX01, was isolated fromP. acidipropioniciATCC 4875 and sequenced. Since the sequencing analysis indicated that pZGX01 could encode 11 proteins, the transcriptional levels of the corresponding genes were also investigated. Then, aP. jensenii-Escherichia colishuttle vector was constructed using the pZGX01 plasmid, theE. colipUC18 plasmid, and a chloramphenicol resistance gene. Interestingly, not only could the developed shuttle vector be transformed intoP. jenseniiATCC 4868 and 4870, but it also could be transformed intofreudenreichiiATCC 6207 subspecies ofP. freudenreichii. Finally, the glycerol dehydrogenase gene (gldA) fromKlebsiella pneumoniaewas expressed inP. jenseniiATCC 4868 with the constructed shuttle vector. In a 3-liter batch culture, the PA production by the engineeredP. jenseniiATCC 4868 strain reached 28.23 ± 1.0 g/liter, which was 26.07% higher than that produced by the wild-type strain (22.06 ± 1.2 g/liter). This result indicated that the constructed vector can be used a useful tool for metabolic engineering ofP. jensenii.