Feedstock-efficient conversion through hydrogen and formate-driven metabolism in Escherichia coli

Area of Science:

• Metabolic Engineering
• Synthetic Biology
• Biotechnology

Background:

• Biomanufacturing yields are limited by coupled energy and carbon metabolism in sugar fermentation.
• Decoupling these processes offers a pathway to enhance production efficiency.

Purpose of the Study:

• To engineer Escherichia coli to utilize hydrogen gas (H2) and formate as external energy and reducing power sources.
• To decouple cellular energy generation from carbon metabolism for improved biomanufacturing.

Main Methods:

• Engineered E. coli with heterologous hydrogenase and formate dehydrogenase enzymes.
• Utilized hydrogen gas and formate supplementation in fermentation processes.
• Performed metabolomic analysis and flux balance analysis to understand metabolic shifts.
• Applied the strategy to mevalonate biosynthesis.

Main Results:

• Achieved significant suppression of acetate oxidation by offsetting electrons with H2 and formate.
• Demonstrated titratable reduction in CO2 evolution with H2 supplementation.
• Observed redirection of carbon flux through the glyoxylate shunt.
• Increased mevalonate titers by 57.6% in engineered strains.

Conclusions:

• Metabolic decoupling using external reducing power is a broadly applicable strategy for biomanufacturing.
• This approach optimizes feedstock and energy utilization, enhancing product yields.
• Engineering E. coli with H2 and formate utilization offers a novel solution to overcome biomanufacturing constraints.