title: The metabolic flux regulation of Klebsiella pneumoniae based on quorum sensing system.
abstract: Quorum-sensing (QS) systems exist universally in bacteria to regulate multiple biological functions. Klebsiella pneumoniae, an industrially important bacterium that produces bio-based chemicals such as 2,3-butanediol and acetoin, can secrete a furanosyl borate diester (AI-2) as the signalling molecule mediating a QS system, which plays a key regulatory role in the biosynthesis of secondary metabolites. In this study, the molecular regulation and metabolic functions of a QS system in K. pneumoniae were investigated. The results showed that after the disruption of AI-2-mediated QS by the knockout of luxS, the production of acetoin, ethanol and acetic acid were relatively lower in the K. pneumoniae mutant than in the wild type bacteria. However, 2,3-butanediol production was increased by 23.8% and reached 54.93 g/L. The observed enhancement may be attributed to the improvement of the catalytic activity of 2,3-butanediol dehydrogenase (BDH) in transforming acetoin to 2,3-butanediol. This possibility is consistent with the RT-PCR-verified increase in the transcriptional level of budC, which encodes BDH. These results also demonstrated that the physiological metabolism of K. pneumoniae was adversely affected by a QS system. This effect was reversed through the addition of synthetic AI-2. This study provides the basis for a QS-modulated metabolic engineering study of K. pneumoniae.
authors.affiliation: College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China.
authors.forename: Shujing
authors.initials: S
authors.lastname: Sun
authors.affiliation: College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China.
authors.forename: Haiyang
authors.initials: H
authors.lastname: Zhang
authors.affiliation: College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China.
authors.forename: Shuyi
authors.initials: S
authors.lastname: Lu
authors.affiliation: College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China.
authors.forename: Chunfen
authors.initials: C
authors.lastname: Lai
authors.affiliation: Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266580, PR China.
authors.forename: Huijun
authors.initials: H
authors.lastname: Liu
authors.affiliation: Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266580, PR China.|College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China.
authors.forename: Hu
authors.initials: H
authors.lastname: Zhu
mesh_terms: D000093:Acetoin / Q000378:metabolism*; D001881:Borates / Q000378:metabolism*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000378:metabolism*; D002072:Butylene Glycols / Q000378:metabolism*; D007711:Klebsiella pneumoniae / Q000378:metabolism*; D053038:Quorum Sensing / Q000502:physiology*
chemical_list: C531128:3A-methyl-5,6-dihydrofuro(2,3-d)(1,3,2)dioxaborole-2,2,6,6A-tetraol; D001881:Borates; D019086:Bridged Bicyclo Compounds, Heterocyclic; D002072:Butylene Glycols; C026978:2,3-butylene glycol; D000093:Acetoin