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The Phosphotransferase System in Solventogenic Clostridia.
1School of Life Sciences, Heriot-Watt University, Edinburgh, UK.
Journal of Molecular Microbiology and Biotechnology
|July 11, 2015
Summary
Understanding sugar uptake by solventogenic clostridia is key to improving biofuel production. Targeting the phosphotransferase system (PTS) and carbon catabolite repression can enhance butanol fermentation performance.
Area of Science:
- Microbiology
- Biotechnology
- Metabolic Engineering
Background:
- Acetone-butanol-ethanol (ABE) fermentation by solventogenic clostridia was historically significant but declined.
- Renewed interest in butanol as a biofuel necessitates optimizing ABE fermentation processes.
- Bacterial carbohydrate utilization, particularly sugar uptake via the phosphotransferase system (PTS), is crucial for efficient fermentation.
Purpose of the Study:
- To investigate the role of phosphotransferase systems (PTS) in clostridial carbohydrate metabolism.
- To understand the regulation of sugar utilization, including glucose repression of other carbon sources.
- To explore strategies for improving fermentation performance by targeting regulatory mechanisms.
Main Methods:
- Genomic analysis to identify phosphotransferases in Clostridium acetobutylicum and C. beijerinckii.
- Experimental characterization of phosphotransferase functions in sugar uptake and phosphorylation.
- Investigation of carbon catabolite repression mechanisms, including the CcpA-dependent pathway.
Main Results:
- Clostridial genomes encode numerous phosphotransferases involved in hexose, hexose derivative, and disaccharide metabolism.
- Glucose significantly represses the utilization of other sugars like xylose and arabinose.
- Targeting the CcpA-dependent carbon catabolite repression pathway effectively reduces glucose repression.
Conclusions:
- Phosphotransferase systems are critical for clostridial sugar metabolism and biofuel production.
- Understanding and manipulating carbon catabolite repression offers a viable strategy for strain improvement.
- Optimizing sugar utilization pathways in clostridia holds promise for enhanced biofuel fermentation.
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