title: Metabolic engineering of Bacillus subtilis to enhance the production of tetramethylpyrazine.
abstract: OBJECTIVE
  Bacillus subtilis BS2, which can produce tetramethylpyrazine (TTMP) from glucose, was engineered by knockout of the 2,3-butanediol (2,3-BD) dehydrogenase gene (bdhA) and then regulated through the addition of 2,3-BD to enhance the TTMP yield.
  
  
  RESULTS
  The bdhA of B. subtilis BS2 was disrupted to construct a TTMP-producing strain termed BSA. In microaerobic flask fermentation, the BSA strain produced 27.8 g TTMP/l. This was 6 g/l higher than that produced by the initial strain. Compared with that in BS2, the maximum yield of acetoin, which is a TTMP precursor, also increased from 11.3 to 16.4 g/l in BSA. The TTMP production by BS2 was enhanced by 2,3-BD supplemented to the fermentation medium. The maximum TTMP and acetoin yields were improved from 21.8 to 29.7 g/l and from 11.3 to 15.4 g/l, respectively, as the 2,3-BD concentration increased from 0 to 3 g/l. Conversely, the yields did not increase when the 2,3-BD concentration in the matrix was ≥4 g/l.
  
  
  CONCLUSIONS
  This study provides valuable information to enhance the TTMP productivity of mutagenic strains through gene manipulation and fermentation optimization.
authors.affiliation: Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, TEDA, Tianjin, 300457, China.|Key Laboratory of Shandong Microbial Engineering, Qilu University of Technology, Jinan, 250353, China.
authors.forename: Wu
authors.initials: W
authors.lastname: Meng
authors.affiliation: Key Laboratory of Shandong Microbial Engineering, Qilu University of Technology, Jinan, 250353, China.
authors.forename: Ruiming
authors.initials: R
authors.lastname: Wang
authors.affiliation: Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, TEDA, Tianjin, 300457, China. xiao99@tust.edu.cn.
authors.forename: Dongguang
authors.initials: D
authors.lastname: Xiao
mesh_terms: D000332:Aerobiosis; D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism*; D002072:Butylene Glycols / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D005285:Fermentation; D017353:Gene Deletion; D005947:Glucose / Q000378:metabolism; D060847:Metabolic Engineering / Q000379:methods*; D010088:Oxidoreductases / Q000235:genetics; D011719:Pyrazines / Q000378:metabolism*; D014665:Vasodilator Agents / Q000378:metabolism*
chemical_list: D002072:Butylene Glycols; D003470:Culture Media; D011719:Pyrazines; D014665:Vasodilator Agents; C026978:2,3-butylene glycol; D010088:Oxidoreductases; D005947:Glucose; C017953:tetramethylpyrazine
keywords: 2,3-Butanediol; 2,3-Butanediol dehydrogenase; Acetoin; Bacillus subtilis; Metabolic engineering; Tetramethylpyrazine