Pyruvate formation and suppression in recombinant Bacillus megaterium cultivation

• Published in: Journal of biotechnology 2004-07, Vol.111 (1), p.89-96
• Main Authors: Hollmann, Rajan, Deckwer, Wolf-Dieter
• Format: Article
• Language: English
• Subjects: B. megaterium; Bacillus megaterium; Bacillus megaterium - classification; Bacillus megaterium - genetics; Bacillus megaterium - growth & development; Bacillus megaterium - metabolism; Biological and medical sciences; Bioreactors - microbiology; Biotechnology; Cell Culture Techniques - methods; Fundamental and applied biological sciences. Psychology; Genetic Enhancement - methods; Glucosyltransferases - genetics; Glucosyltransferases - metabolism; High cell density cultivation; Pyruvate; Pyruvic Acid - metabolism; Recombination, Genetic - genetics; Species Specificity; Sucrose - metabolism
• ISSN: 0168-1656; 1873-4863
• DOI: 10.1016/j.jbiotec.2004.03.006

A recombinant Bacillus megaterium strain showed the ability to secrete large amounts of pyruvate (up to 27.8 g l −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.