title: Metabolic engineering ofSerratia marcescensMG1 for enhanced production of (3R)-acetoin.
abstract: BACKGROUND
  Optically pure acetoin (AC) is an important platform chemical which has been widely used to synthesize novel optically active α-hydroxyketone derivatives and liquid crystal composites.
  
  
  RESULTS
  In this study,slaC andgldA encodingmeso-2,3-butanediol dehydrogenase (meso-2,3-BDH) and glycerol dehydrogenase (GDH), respectively, inS. marcescensMG1 were knocked out to block the conversion from AC to 2,3-butanediol (2,3-BD). The resulting strain MG14 was found to produce a large amount of optically pure (3R)-AC with a little 2,3-BD, indicating that another enzyme responsible for 2,3-BD formation exceptmeso-2,3-BDH and GDH existed in the strain MG1. Furthermore, SlaR protein, a transcriptional activator of AC cluster, was overexpressed usingPCpromoter in the strain MG14, leading to enhancement of the (3R)-AC yield by 29.91%. The recombinant strain with overexpression of SlaR, designated asS. marcescensMG15, was used to perform medium optimization for improving (3R)-AC production.
  
  
  CONCLUSIONS
  Under the optimized conditions, 39.91 ± 1.35 g/l (3R)-AC was produced by strain MG15 with the productivity of 1.11 g/l h and the conversion rate of 80.13%.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, East China University of Science and Technology, Shanghai, 200237 China.
authors.forename: Xin
authors.initials: X
authors.lastname: Lv
authors.affiliation: State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, East China University of Science and Technology, Shanghai, 200237 China.
authors.forename: Lu
authors.initials: L
authors.lastname: Dai
authors.affiliation: State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, East China University of Science and Technology, Shanghai, 200237 China.
authors.forename: Fangmin
authors.initials: F
authors.lastname: Bai
authors.affiliation: State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, East China University of Science and Technology, Shanghai, 200237 China.
authors.forename: Zhanqing
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian China.
authors.forename: Liaoyuan
authors.initials: L
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, East China University of Science and Technology, Shanghai, 200237 China.
authors.forename: Yaling
authors.initials: Y
authors.lastname: Shen
keywords: (3R)-AC; 3-Butanediol dehydrogenase; Glycerol dehydrogenase; Meso-2; Serratia marcescens MG1; SlaR; Transcriptional regulator