A comparison between aerobic growth of Bacillus licheniformis in continuous culture and partial-recycling fermentor, with contributions to the discussion on maintenance energy demand

• Published in: Archives of microbiology Vol. 152; no. 5; pp. 499 - 507
• Main Authors: Bulthuis, Ben A., Koningstein, Gregory M., Stouthamer, Adriaan H., van Verseveld, Henk W.
• Format: Journal Article
• Language: English
• Published: 01-10-1989
• ISSN: 0302-8933; 1432-072X
• DOI: 10.1007/BF00446937

Energy costs of biomass synthesis are relatively higher at low than at high specific growth rates ( mu ) because of an increased protein content of the cell and increased costs of protein synthesis as such at low mu values. A comparison of aerobic, glucose limited cultures of Bacillus licheniformis in a chemostat and in a partial-recycling fermentor indicated that pulse-wise nutrient addition increased the maintenance energy demand (m). In the chemostat experiments, we also found a striking deviation from linearity between substrate consumption and mu , with large implications for the maintenance coefficient. The deviation is mainly due to a large shift in metabolic carbon flows at specific growth rates between 50 and 100% of mu sub(max). At those growth rates, uncoupled growth occurs, presumably as a necessary condition for faster growth, since uncoupling results in a faster energy-supply for biosynthetic purposes.