title: Over-expression of glucose dehydrogenase improves cell growth and riboflavin production in Bacillus subtilis.
abstract: Ribulose 5-phosphate is a precursor for riboflavin biosynthesis. Alteration of carbon flow into the pentose phosphate pathway will affect the availability of ribulose 5-phosphate and the riboflavin yield. We have modulated carbon flow in Bacillus subtilis through the gluconate bypass by over-expression of glucose dehydrogenase under the control of the constitutively expressed P43 promoter. Over-expression of glucose dehydrogenase resulted in low acid production (acetate and pyruvate). The substantial reduction in acid production is accompanied by increased riboflavin production and an increased rate of growth while glucose consumption remained unchanged. Metabolic analysis indicated that over-expression of glucose dehydrogenase increased intracellular pool of ribulose 5-phosphate. The high concentrations of ribulose 5-phosphate could explain the increased riboflavin production.
authors.affiliation: Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, P. R. China.
authors.forename: Yingbo
authors.initials: Y
authors.lastname: Zhu
authors.forename: Xun
authors.initials: X
authors.lastname: Chen
authors.forename: Tao
authors.initials: T
authors.lastname: Chen
authors.forename: Shuobo
authors.initials: S
authors.lastname: Shi
authors.forename: Xueming
authors.initials: X
authors.lastname: Zhao
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D001412:Bacillus subtilis / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D003001:Cloning, Molecular; D042843:Glucose 1-Dehydrogenase / Q000096:biosynthesis* / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D011401:Promoter Regions, Genetic; D019289:Pyruvic Acid / Q000378:metabolism; D012256:Riboflavin / Q000096:biosynthesis*
chemical_list: D019289:Pyruvic Acid; D042843:Glucose 1-Dehydrogenase; D019342:Acetic Acid; D012256:Riboflavin