The influence of budA deletion on glucose metabolism related in 2,3-butanediol production by Klebsiella pneumoniae

• We attempted to understand the effects of blocked 2,3-BDO pathway on K. pneumoniae.
• We constructed K. pneumoniaeΔwabGΔbudA.
• We analyzed carbon flux distribution, transcriptome and extracellular amino acid concentration.
• This study provides an insight of K. pneumoniae glucose metabolism.

Klebsiella pneumoniae (K. pneumoniae), which is a promising microorganism for industrial bulk production of 2,3-butanediol (2,3-BDO), naturally converts glucose to 2,3-BDO. The 2,3-BDO biosynthesis from glucose is composed of three steps; α-acetolactate biosynthesis by α-acetolactate synthase (budB); acetoin biosynthesis by α-acetolactate decarboxylase (budA); and 2,3-BDO biosynthesis by acetoin reductase (budC). In an effort to understand the influence of blocked 2,3-BDO pathway on K. pneumoniae glucose metabolism by budA deletion, we constructed K. pneumoniaeΔwabGΔbudA (SGSB106). Carbon flux distribution analysis, transcriptome analysis and extracellular amino acid concentration analysis were carried out to understand the effects of the budA deletion, and K. pneumoniaeΔwabG (SGSB100) was used as a control strain. Approximately 50.3% decrease in CO2 emission; and approximately 3.8-fold increase in amino acid production was observed in SGSB106. In addition to, among the amino acids, valine production significantly increased, suggesting that the branched-chain amino acid biosynthesis (BACC) in SGSB106 was activated by deletion of budA. Furthermore, whole genome transcriptome analysis of SGSB106 and SGSB100, correlates with the results from carbon distribution and amino acids concentration analyses.