Observation of 2,3-butanediol biosynthesis in Lys regulator mutated Klebsiella pneumoniae at gene transcription level.
Microorganisms that produce 2,3-butanediol (2,3-BDO) are mostly mixed acid fermentation microorganisms, and they synthesize 2,3-BDO in order to suppress medium acidification. The 2,3-BDO operon (budBAC) is activated by the LysR regulator protein derived from the budR. In this study, the effect of the budR on 2,3-BDO-biosynthesis was observed at gene transcription level. The Klebsiella pneumoniae strains (wabG-deleted strain (SGSB100), budR over-expressed strain (SGSB101), and the budR-deleted strain (SGSB102)) were constructed. The resulting strains were cultivated in unified conditions. Samples were obtained at the lag-, log-, and stationary-phase of cell growth, and gene transcription levels of the budR, 2,3-BDO-biosynthesis-related (budB, budA, and budC), and acid-biosynthesis-related (ldhA and ack) genes were observed. During the lag-phase of cell growth in SGSB101, the budR transcription level increased approximately 8-fold, and 2,3-BDO production increased approximately 2-fold, when compared to SGSB100. Also in SGSB101 the transcription level of the acid-biosynthesis-related genes (ldhA and ack) increased approximately up to 11-fold during the lag-phase of cell growth compared to SGSB100. On contrast, in SGSB102 budR transcription was not detected, and the transcription level of the acid-biosynthesis-related genes (ldhA and ack) decreased approximately 70-fold during the lag-phase of cell growth compared to SGSB100. This is by far the first observation of 2,3-BDO regulation mechanism at gene transcription level in K. pneumoniae, and therefore may be useful for understanding and improving 2,3-BDO biosynthesis metabolic network.
Department of Chemical and Biomolecular Engineering, Sogang University, Seoul 121-742, South Korea.
Soojin
S
Lee
Borim
B
Kim
Daun
D
Jeong
Minkyu
M
Oh
Youngsoon
Y
Um
Young-Rok
YR
Kim
Jungwook
J
Kim
Jinwon
J
Lee
D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002072:Butylene Glycols / Q000138:chemical synthesis / Q000378:metabolism*; D005285:Fermentation; D007711:Klebsiella pneumoniae / Q000235:genetics / Q000378:metabolism*; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; D002072:Butylene Glycols; D014157:Transcription Factors; C026978:2,3-butylene glycol; C073470:LysR protein, Bacteria
2,3-Butanediol; Klebsiella pneumoniae; Putative LysR-family transcriptional regulator; Real-time PCR; budR