Pyruvate formation and suppression in recombinant Bacillus megaterium cultivation.
A recombinant Bacillus megaterium strain showed the ability to secrete large amounts of pyruvate (up to 27.8 gl( -1)) for growth rates larger than 0.15 h(-1). Cultivation below this growth rate avoids pyruvate formation while minimizing acetate and succinate production. Using exponential feeding, final biomass concentrations of up to 80 g l(-1) were achieved. Overall molar yields for the experiments with pyruvate formation were as high as 0.79 mol mol(-1). Pyruvate formation was caused by the discrepancy between glycolytic and pyruvate dehydrogenase reaction/tricarboxylic acid cycle capacities during glucose excess. High pyruvate resulted in deceleration and subsequent cessation of growth. In addition, this inhibitory effect is likely associated with the phoshoenolpyruvate:glucose phosphotransferase system used by B. megaterium as the main importer for glucose.
Hollmann
Rajan
R
TU-BCE, Technical University Braunschweig, Mascheroder Weg 1, 38124 Braunschweig, Germany.
Deckwer
Wolf-Dieter
WD
D001410:Bacillus megaterium / Q000145:classification / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000379:methods*; D024861:Genetic Enhancement / Q000379:methods*; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D019289:Pyruvic Acid / Q000378:metabolism*; D011995:Recombination, Genetic / Q000235:genetics; D013045:Species Specificity; D013395:Sucrose / Q000378:metabolism*
D013395:Sucrose; D019289:Pyruvic Acid; D005964:Glucosyltransferases; C020025:dextransucrase