| 초록 |
Mannheimia succiniciproducens MBEL55E produces succinic acid in high concentrations as a fermentation end product. The cells could not grow below 8.74 mM of dissolved CO2, indicating that there is a threshold level of CO2 to sustain the growth of M. succiniciproducens. Succinic acid yield on glucose was 1.49 and 1.52 times higher at 141 mM CO2 than those obtained from 8.74 mM CO2, respectively. Through the result of enzyme activities, we focus on the efficient carboxylation of phosphoenolpyruvate (PEP) to oxaloacetate, in which CO2-fixation occurs by both PEP carboxykinase (PckA) and PEP carboxylase (Ppc), allows M. succiniciproducens to produce substantial amounts of succinic acid. In particular, the activity of PckA was more than 50 times higher than those of Ppc and malic enzyme (SfcA). [This work was supported by the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government (MOST) (2005-01294). Further supports by the LG Chem Chair Professorship, IBM SUR program, Microsoft, and by the KOSEF through the Center for Ultramicrochemical Process Systems are appreciated.]. |
