APPLICATIONS OF TECHNOLOGY:
- Precursors of industrial chemicals
- Improves isopentenol production at fermentor scale
- Allows for improved isopentenol generation under anaerobic or microaerobic conditions
- Provides a screening platform with enhanced efficiency for screening various mutant libraries
A research team led by Taek Soon Lee at the Joint BioEnergy Institute (JBEI) has invented a technology to identify a phosphomevalonate decarboxylase (PMD) enzyme with higher activity to increase production of isopentenol, a biofuel and precursor of industrial chemicals such as isoprene.
The isopentenol biosynthesis pathway accumulates a toxic intermediate, isopentenyl diphosphate (IPP), which requires highly aerated fermentation conditions and ATP for biosynthesis. An alternate IPP-bypassing pathway uses the PMD enzyme to reduce IPP toxicity and increase isopentenol production under aeration-limited conditions. To enhance PMD enzyme activity to produce more isopentenol, researchers developed a high-throughput screening platform to monitor cell growth and enzymatic activity of mutant PMD enzymes in engineered E. coli host cells. The research team identified multiple PMD mutants that had increased activity to significantly improve isopentenol production compared to wild type cells. The screening platform was validated using PMD mutants of known activity.
Previous work with the isopentenol pathway shows that the highest titers and yield have been achieved by engineering the IPP-bypassing pathway and optimizing the pathway based on analysis of reaction intermediates and enzyme expression levels. By providing a screening platform to monitor PMD enzyme activity, the JBEI approach provides a method to significantly increase isopentenol titer from the current titer and improve efficiency for screening numerous mutant libraries over traditional chromatography-based screening methods, such as gas chromatography.
DEVELOPMENT STAGE: Proven principle
FOR MORE INFORMATION: Kang, A., Meadows, C. W., Canu, N., Keasling, J. D., & Lee, T. S. (2017). High-throughput enzyme screening platform for the IPP-bypass mevalonate pathway for isopentenol production. Metabolic Engineering, 41, 125–134. https://doi.org/10.1016/j.ymben.2017.03.010
STATUS: Published U. S. Patent Application 15/943,632 (Publication No. 2018/0362970). Available for licensing or collaborative research.
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