title: Glucosamine as carbon source for amino acid-producing Corynebacterium glutamicum.
abstract: Corynebacterium glutamicum grows with a variety of carbohydrates and carbohydrate derivatives as sole carbon sources; however, growth with glucosamine has not yet been reported. We isolated a spontaneous mutant (M4) which is able to grow as fast with glucosamine as with glucose as sole carbon source. Glucosamine also served as a combined source of carbon, energy and nitrogen for the mutant strain. Characterisation of the M4 mutant revealed a significantly increased expression of the nagB gene encoding the glucosamine-6P deaminase NagB involved in degradation of glucosamine, as a consequence of a single mutation in the promoter region of the nagAB-scrB operon. Ectopic nagB overexpression verified that the activity of the NagB enzyme is in fact the growth limiting factor under these conditions. In addition, glucosamine uptake was studied, which proved to be unchanged in the wild-type and M4 mutant strains. Using specific deletion strains, we identified the PTS(Glc) transport system to be responsible for glucosamine uptake in C. glutamicum. The affinity of this uptake system for glucosamine was about 40-fold lower than that for its major substrate glucose. Because of this difference in affinity, glucosamine is efficiently taken up only if external glucose is absent or present at low concentrations. C. glutamicum was also examined for its suitability to use glucosamine as substrate for biotechnological purposes. Upon overexpression of the nagB gene in suitable C. glutamicum producer strains, efficient production of both the amino acid L-lysine and the diamine putrescine from glucosamine was demonstrated.
authors.affiliation: Institute of Biochemistry, University of Cologne, 50674 Cologne, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Uhde
authors.forename: Jung-Won
authors.initials: JW
authors.lastname: Youn
authors.forename: Tomoya
authors.initials: T
authors.lastname: Maeda
authors.forename: Lina
authors.initials: L
authors.lastname: Clermont
authors.forename: Christian
authors.initials: C
authors.lastname: Matano
authors.forename: Reinhard
authors.initials: R
authors.lastname: Krämer
authors.forename: Volker F
authors.initials: VF
authors.lastname: Wendisch
authors.forename: Gerd M
authors.initials: GM
authors.lastname: Seibold
authors.forename: Kay
authors.initials: K
authors.lastname: Marin
mesh_terms: D019747:Aldose-Ketose Isomerases / Q000235:genetics / Q000378:metabolism; D000596:Amino Acids / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002244:Carbon / Q000378:metabolism; D048230:Corynebacterium glutamicum / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D005944:Glucosamine / Q000378:metabolism*; D017354:Point Mutation; D011401:Promoter Regions, Genetic
chemical_list: D000596:Amino Acids; D001426:Bacterial Proteins; D002244:Carbon; C020582:glucosamine-6-phosphate isomerase; D019747:Aldose-Ketose Isomerases; D005944:Glucosamine