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A metabolic pathway for catabolizing levulinic acid in bacteria
Jacqueline M Rand1, Tippapha Pisithkul2, Ryan L Clark1
1Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA.
Nature Microbiology
|September 27, 2017
Summary
Researchers identified a seven-gene operon enabling levulinic acid (LA) breakdown in Pseudomonas putida. This discovery advances biorefining by enabling efficient use of biomass-derived LA as a feedstock for industrial bioconversions.
Area of Science:
- Microbiology
- Biochemistry
- Metabolic Engineering
Background:
- Microorganisms offer potential for industrial bioconversions but metabolic pathways for feedstocks like levulinic acid (LA) are often unknown.
- LA is a biomass-derived carbon source, yet its catabolism genetics remain uncharacterized.
Purpose of the Study:
- To identify and characterize the genetic basis of levulinic acid (LA) catabolism in Pseudomonas putida KT2440.
- To enable efficient utilization of LA in biorefining and metabolic engineering.
Main Methods:
- Identification and characterization of a seven-gene operon responsible for LA assimilation.
- Reconstitution of the pathway with purified proteins to analyze intermediates.
- Adaptive evolution of Escherichia coli for robust LA growth using the identified enzymes.
Main Results:
- A seven-gene operon enabling LA catabolism in P. putida was identified.
- Four acyl-CoA intermediates, including novel 4-phosphovaleryl-CoA, were observed.
- Engineered E. coli demonstrated robust growth on LA, utilizing enzymes from the P. putida operon.
Conclusions:
- The identified operon provides the genetic framework for levulinic acid assimilation.
- This work facilitates metabolic engineering for enhanced bioconversion of biomass hydrolysates.
- Enables more efficient use of LA as a sustainable feedstock.
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