Influence of carbon sources on biosynthesis of 1,3-propandiol,raw material of PTT,and its regulation to DhaB in Klebsiella pneumonia

The yield of 1,3-propandiol(PDO) is a bottleneck of the industrial application of polytrimethylene tereph thalate(PTT).In order to increase the titer of PDO,the influences of different carbon sources on the carbon fluxes and the transcription and activity of key enzyme DhaB during the biosynthesis of PDO by Klebsiella pneumonia ZG25 were studied.The results indicated that glucose can not be directly used for synthesis of PDO in the presence of K.pneumonia ZG25.The PDO yield of K.pneumonia ZG25 by using glycerol as the sole carbon source achieved 9 g /L and cell growth is inhibited to a certain extent.When glycerol is used as the substrate and 5 g /L glucose was applied as supplementary carbon source,the biomass was increased by 66.7%,the mRNA level of DhaB and the activity of DhaB were also increased by 20% and 64%,respectively,and the yield of PDO was increased to 1.5 times.These results suggest that the mixed carbon sources strategy can activate the transcription of DhaB,enhance the activity of DhaB and strengthen the synthesis of PDO by K.pneumonia.