Heterologous expression of lactose- and galactose-utilizing pathways from lactic acid bacteria in Corynebacterium glutamicum for production of lysine in whey.
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.
Barrett
Eoin
E
Dairy Products Research Centre, Teagasc, Moorepark, Fermoy, Ireland.
Stanton
Catherine
C
Zelder
Oskar
O
Fitzgerald
Gerald
G
Ross
R Paul
RP
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
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