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Updated: Aug 13, 2026
08:57
Simultaneous Measurement of Superoxide/Hydrogen Peroxide and NADH Production by Flavin-containing Mitochondrial Dehydrogenases
Published on: February 24, 2018
Redox-guided dynamic regulation for enhanced bioproduction using engineered NADH/NAD⁺ biosensors
Jianli Zhang1, Qi Gan1, Xinyu Gong1
1School of Chemical, Materials and Biomedical Engineering, College of Engineering, The University of Georgia, Athens 30602, GA, USA.
Bioresource Technology
|August 10, 2026
Summary
Researchers engineered a novel biosensor to precisely control microbial production by monitoring and balancing cellular redox states. This innovation enhances the efficiency of producing valuable chemicals like mevalonate.
Area of Science:
- Biotechnology
- Metabolic Engineering
- Synthetic Biology
Background:
- Efficient microbial production relies on balancing carbon flux and intracellular redox state (NADH/NAD+ ratio).
- NADH/NAD+ imbalance frequently limits the performance of synthetic pathways dependent on these cofactors.
Purpose of the Study:
- To engineer a transcription factor Rex-based biosensor for sensing and guiding microbial redox states.
- To optimize microbial production of value-added chemicals by dynamically regulating metabolic pathways based on intracellular redox status.
Main Methods:
- Engineered a Staphylococcus aureus Rex transcription factor-based biosensor for NADH/NAD+ sensing in Escherichia coli.
- Systematically tuned intracellular redox states using NADH-consuming and generating enzymes for biosensor characterization.
- Employed rational mutagenesis to create a Rex variant (Rexm) with an expanded operational range.
- Integrated the biosensor into a dynamic regulatory circuit to control glycolysis and enhance mevalonate biosynthesis.
Main Results:
- The optimized biosensor demonstrated a 4.37-fold dynamic range for decreased NADH/NAD+ ratios.
- The Rexm variant showed a 3.14-fold response to increased NADH/NAD+ ratios.
- The dynamic regulatory circuit increased mevalonate titer by 28% (to 6.23 g/L) by balancing NADH supply and carbon flux.
Conclusions:
- Engineered Rex-based biosensors offer a tunable platform for intracellular redox sensing.
- Dynamic regulation guided by these biosensors enhances microbial production of chemicals.
- This approach provides a robust strategy for optimizing metabolic pathways and improving yields.
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