title: Engineering Bacillus subtilis for acetoin production from glucose and xylose mixtures.
abstract: As a vital flavor compound, acetoin is extensively used in dairy products and drinks industry. In this study, Bacillus subtilis was engineered to metabolize glucose and xylose as substrates for acetoin production. Initially, gene araE from B. subtilis, encoding the xylose transport protein AraE, was placed under the control of the constitutive promoter P43 for over-expression. Batch cultures showed that 10 g/L xylose was depleted completely in 32 h. Subsequently, genes xylA and xylB from Escherichia coli, encoding xylose isomerase and xylulokinase respectively, were introduced into B. subtilis, and the recombinant turned out to assimilate glucose and xylose without preference. In shake-flask fermentations, 5.5 g/L acetoin with a yield of 0.70 mol(mol sugar)(-1) was obtained by the optimum strain BSUL13 under microaerobic conditions, which offered a metabolic engineering strategy on engineering microbe as cell factory for the production of high-valued chemicals from renewable resource.
authors.affiliation: Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin 300072, People's Republic of China; Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China. Electronic address: chentao@tju.edu.cn.
authors.forename: Tao
authors.initials: T
authors.lastname: Chen
authors.forename: Wei-xi
authors.initials: WX
authors.lastname: Liu
authors.forename: Jing
authors.initials: J
authors.lastname: Fu
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.forename: Ya-jie
authors.initials: YJ
authors.lastname: Tang
mesh_terms: D000093:Acetoin / Q000138:chemical synthesis / Q000378:metabolism*; D001412:Bacillus subtilis / Q000201:enzymology / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005285:Fermentation; D005818:Genetic Engineering; D005947:Glucose / Q000737:chemistry / Q000378:metabolism; D060847:Metabolic Engineering; D014994:Xylose / Q000737:chemistry / Q000378:metabolism
chemical_list: D014994:Xylose; D000093:Acetoin; D005947:Glucose
keywords: Acetoin; Bacillus subtilis; Carbon catabolite repression; Metabolic engineering; Xylose