title: Expression of Vitreoscilla hemoglobin enhances cell growth and dihydroxyacetone production in Gluconobacter oxydans.
abstract: Dihydroxyacetone (DHA) is an important ketose sugar, which is extensively used in the cosmetic, chemical, and pharmaceutical industries. DHA has been industrially produced by Gluconobacter oxydans with a high demand of oxygen. To improve the production of DHA, the gene vgb encoding Vitreoscilla hemoglobin (VHb) was successfully introduced into G. oxydans, where it was stably maintained, and expressed at about 76.0 nmol/g dry cell weight. Results indicated that the constitutively expressed VHb improved cell growth and DHA production in G. oxydans under different aeration conditions. Especially at low aeration rates, the VHb-expressing strain (VHb(+)) displayed 23.13% more biomass and 37.36% more DHA production than those of VHb-free strain (VHb(-)) after 32 h fermentation in bioreactors. In addition, oxygen uptake rate (OUR) was also increased in VHb(+) strain relative to the control strain during fermentation processes.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, Institute of Newworld Biotechnology, East China University of Science and Technology, Shanghai, China. limh09@hotmail.com
authors.forename: Minghua
authors.initials: M
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Wu
authors.forename: Jinping
authors.initials: J
authors.lastname: Lin
authors.forename: Dongzhi
authors.initials: D
authors.lastname: Wei
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D019149:Bioreactors; D004098:Dihydroxyacetone / Q000096:biosynthesis*; D005285:Fermentation; D015870:Gene Expression; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D024861:Genetic Enhancement / Q000379:methods; D005822:Genetic Vectors; D020600:Gluconobacter oxydans / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D021141:Nucleic Acid Amplification Techniques; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption / Q000235:genetics; D010957:Plasmids; D011994:Recombinant Proteins / Q000096:biosynthesis; D011995:Recombination, Genetic; D014169:Transformation, Bacterial; D054793:Truncated Hemoglobins / Q000235:genetics* / Q000378:metabolism*; D020589:Vitreoscilla / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D054793:Truncated Hemoglobins; C082613:hemoglobin protein, Vitreoscilla; D004098:Dihydroxyacetone; D010100:Oxygen