Impact of the heterologous expression of xylose isomerase gene on the biosynthesis of 1,3-propanediol by Klebsiella pneumoniae

Abstract:

[Objective] In order to enhance the production of 1,3-propanediol by Klebsiella pneumoniae, the regeneration of reducing power was strengthened. [Methods] The xylose isomerase gene (xylA) from Escherichia coli was cloned and expressed in Klebsiella pneumoniae. The relevant metabolites and NADH concentrations of the recombinant strain were analyzed when it was cultured with xylose and glycerol as co-substrates. [Results] The intracellular reducing equivalent of the recombinant Klebsiella pneumoniae was increased by 0.1?0.3 fold. The titer of 1,3-propanediol of the recombinant strain reached 23.31 g/L, which was 20% higher than that of the parent strain. The conversion rate of 1,3-propanediol of the genetic engineered Klebsiella pneumoniae was improved from 0.60 mol/mol to 0.73 mol/mol. [Conclusion] The xylose metabolic pathway and intracellular reducing power is enhanced with the expression of xylA gene, resulted in the improved 1,3-propanediol concentration.

Key words:Klebsiella pneumoniae, 1,3-Propanediol, Xylose, Xylose isomerase, NADH