title: Production of a periplasmic trehalase in Gluconobacter oxydans and growth on trehalose.
abstract: Gluconobacter strains are specialized in the incomplete oxidation of monosaccharides. In contrast, growth and product formation from disaccharides is either very low or impossible. A pathway that allows growth on trehalose was rationally designed to broaden the substrate range of Gluconobacter oxydans. Expression vectors containing different signal sequences and the gene encoding alkaline phosphatase, phoA, from Escherichia coli were constructed. The signal peptide that exhibited the strongest periplasmic PhoA activity was used to generate a G. oxydans strain able to utilize the model disaccharide trehalose as a carbon and energy source by expressing the periplasmic trehalase TreA from E. coli. The strain had a doubling time of 3.7h and reached a final optical density of 1.7 when trehalose was used as a growth substrate. In comparison, the wild-type harboring the empty vector and the strain expressing treA without a signal sequence grew slowly to a final OD of only 0.15. The trehalose concentration in treA expressing cultures decreased continuously during the exponential growth phase indicating that the substrate was hydrolyzed to glucose by TreA. In contrast to the wild-type growing on glucose, the treA expression strain mainly formed acetate and 5-ketogluconate as end products rather than gluconate.
authors.affiliation: Institute of Microbiology and Biotechnology, University of Bonn, 168 Meckenheimer Allee, 53115 Bonn, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Kosciow
authors.affiliation: Institute of Microbiology and Biotechnology, University of Bonn, 168 Meckenheimer Allee, 53115 Bonn, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Zahid
authors.affiliation: Missouri State University, Biology Department, 901 S. National Avenue, Springfield, MO 65897, United States.
authors.forename: P
authors.initials: P
authors.lastname: Schweiger
authors.affiliation: Institute of Microbiology and Biotechnology, University of Bonn, 168 Meckenheimer Allee, 53115 Bonn, Germany. Electronic address: udeppen@uni-bonn.de.
authors.forename: U
authors.initials: U
authors.lastname: Deppenmeier
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D005798:Genes, Bacterial; D020600:Gluconobacter oxydans / Q000378:metabolism*; D021382:Protein Sorting Signals / Q000502:physiology; D014198:Trehalase / Q000378:metabolism*; D014199:Trehalose / Q000378:metabolism*
chemical_list: D021382:Protein Sorting Signals; D014199:Trehalose; D014198:Trehalase; D019342:Acetic Acid
keywords: Acetic acid bacteria; Genetic tool; Incomplete oxidation; Signal peptide; Substrate spectrum