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Engineering E. coli for simultaneous glucose-xylose utilization during methyl ketone production.
Xi Wang1,2, Ee-Been Goh1,2, Harry R Beller3,4,5
1Joint BioEnergy Institute (JBEI), 5885 Hollis St., Emeryville, CA, 94608, USA.
Microbial Cell Factories
|January 29, 2018
Summary
Engineered E. coli efficiently consumes both glucose and xylose simultaneously, boosting methyl ketone production for biofuels and fragrances. This overcomes previous limitations in sugar utilization for industrial applications.
Area of Science:
- Metabolic Engineering
- Synthetic Biology
- Biotechnology
Background:
- Developed E. coli for medium-chain methyl ketone overproduction.
- Strain optimized for glucose utilization, but not xylose.
- Lignocellulosic hydrolysates contain both glucose and xylose.
Purpose of the Study:
- Engineer E. coli for simultaneous glucose and xylose consumption.
- Improve methyl ketone production efficiency.
- Overcome carbon catabolite repression for enhanced biofuel precursor synthesis.
Main Methods:
- Genetic manipulation to alleviate carbon catabolite repression.
- Engineered constitutive expression of xylose transport and metabolism genes (xylF and xylA).
- Implemented chromosomal deletion of pgi and downregulated CRP expression.
Main Results:
- Synchronized glucose and xylose consumption achieved with xylF and xylA constitutive expression.
- Initial engineered strain showed a fivefold decrease in methyl ketone titer.
- Deletion of pgi and CRP downregulation restored and maintained methyl ketone titer.
- Optimized strain demonstrated simultaneous sugar utilization without titer compromise at 1-2% total sugar.
Conclusions:
- Demonstrated a strategy for engineering simultaneous C6 and C5 sugar utilization in E. coli.
- Achieved efficient methyl ketone production with dual sugar consumption.
- Enabled potential for improved biofuel and flavor/fragrance compound synthesis from lignocellulosic biomass.
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