期刊
METABOLIC ENGINEERING
卷 12, 期 5, 页码 446-454出版社
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.ymben.2010.05.002
关键词
Clostridium acetobutylicum; Disruption of ccpA; D-glucose/D-xylose mixture utilization
资金
- National Basic Research Program of China [973: 2007CB707803]
- National High-tech Research and Development Program of China [863: 2007AA05Z407]
- Chinese Academy of Sciences [KSCX2-YW-G-075]
- Planned Scientific Program of Science and Technology Commission of Shanghai Municipality [08dz1207100]
- National Natural Science Foundation of China
d-xylose utilization is a key issue for lignocellulosic biomass fermentation, and a major problem in this process is carbon catabolite repression (CCR). In this investigation, solvent-producing bacterium Clostridium acetobutylicum ATCC 824 was metabolically engineered to eliminate d-glucose repression of d-xylose utilization. The ccpA gene, encoding the pleiotropic regulator CcpA, was experimentally characterized and then disrupted. Under pH-controlled conditions, the ccpA-disrupted mutant (824ccpA) can use a mixture of d-xylose and d-glucose simultaneously without CCR. Moreover, this engineered strain produced acetone, butanol and ethanol (ABE) at a maximal titer of 4.94, 12.05 and 1.04 g/L, respectively, which was close to the solvent level of maize- or molasses-based fermentation by wild type C. acetobutylicum. Molar balance analysis for improved process of mixed sugars utilization also revealed less acid accumulation and more butanol yield by the engineered strain as compared to the wild type. This study offers a genetic modification strategy for improving simultaneous utilization of mixed sugars by Clostridium, which is essential for commercial exploitation of lignocellulose for the production of solvents and biofuels. (C) 2010 Elsevier Inc. All rights reserved.
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