title: Heterologous expression of lactose- and galactose-utilizing pathways from lactic acid bacteria in Corynebacterium glutamicum for production of lysine in whey.
abstract: The genetic determinants for lactose utilization from Lactobacillus delbrueckii subsp. bulgaricus ATCC 11842 and galactose utilization from Lactococcus lactis subsp. cremoris MG 1363 were heterologously expressed in the lysine-overproducing strain Corynebacterium glutamicum ATCC 21253. The C. glutamicum strains expressing the lactose permease and beta-galactosidase genes of L. delbrueckii subsp. bulgaricus exhibited beta-galactosidase activity in excess of 1000 Miller units/ml of cells and were able to grow in medium in which lactose was the sole carbon source. Similarly, C. glutamicum strains containing the lactococcal aldose-1-epimerase, galactokinase, UDP-glucose-1-P-uridylyltransferase, and UDP-galactose-4-epimerase genes in association with the lactose permease and beta-galactosidase genes exhibited beta-galactosidase levels in excess of 730 Miller units/ml of cells and were able to grow in medium in which galactose was the sole carbon source. When grown in whey-based medium, the engineered C. glutamicum strain produced lysine at concentrations of up to 2 mg/ml, which represented a 10-fold increase over the results obtained with the lactose- and galactose-negative control, C. glutamicum 21253. Despite their increased catabolic flexibility, however, the modified corynebacteria exhibited slower growth rates and plasmid instability.
authors.affiliation: Dairy Products Research Centre, Teagasc, Moorepark, Fermoy, Ireland.
authors.forename: Eoin
authors.initials: E
authors.lastname: Barrett
authors.forename: Catherine
authors.initials: C
authors.lastname: Stanton
authors.forename: Oskar
authors.initials: O
authors.lastname: Zelder
authors.forename: Gerald
authors.initials: G
authors.lastname: Fitzgerald
authors.forename: R Paul
authors.initials: RP
authors.lastname: Ross
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003352:Corynebacterium / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D003470:Culture Media; D005690:Galactose / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005818:Genetic Engineering / Q000379:methods; D007778:Lactobacillus / Q000201:enzymology / Q000235:genetics; D013294:Lactococcus lactis / Q000201:enzymology / Q000235:genetics; D007785:Lactose / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D008894:Milk Proteins / Q000378:metabolism*; D014169:Transformation, Bacterial; D000067816:Whey Proteins; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D026901:Membrane Transport Proteins; D008894:Milk Proteins; D000067816:Whey Proteins; C021499:lactose permease; D001616:beta-Galactosidase; D007785:Lactose; D008239:Lysine; D005690:Galactose