Bio-Inspired Microreactors Continuously Synthesize Glucose Precursor from CO₂ with an Energy Conversion Efficiency...

Area of Science:

• Biotechnology
• Chemical Engineering
• Artificial Photosynthesis

Background:

• Excessive atmospheric CO2 and food scarcity are critical global challenges.
• Natural photosynthesis, while converting CO2 to food, suffers from low energy efficiency due to limitations in the RuBisCO enzyme.
• Prior efforts focused on enzyme engineering, but this study explores reactor design for improved efficiency.

Purpose of the Study:

• To design and develop a novel microreactor that mimics the thylakoid structure of chloroplasts.
• To immobilize the enzyme D-ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) for enhanced CO2 conversion.
• To improve the efficiency, stability, and reusability of RuBisCO for artificial photosynthesis.

Main Methods:

• Utilized a layer-by-layer strategy to immobilize RuBisCO within a microreactor, mimicking thylakoid stacking.
• Measured the continuous conversion rate of CO2 into glucose precursor.
• Assessed enzyme activity, stability, and reusability compared to free RuBisCO.
• Scaled the microreactor system in parallel to evaluate production capacity and energy conversion efficiency.

Main Results:

• Achieved continuous CO2 conversion into glucose precursor at 1.9 nmol min⁻¹.
• Demonstrated a 1.5-fold increase in enzyme activity and an approximately 8-fold increase in stability compared to free RuBisCO.
• Reported high reusability of the immobilized enzyme, with 96% retention after 10 reuse cycles.
• Scaled-out reactors achieved a production rate of 15.8 nmol min⁻¹ with 3.3 times higher energy conversion efficiency than rice.

Conclusions:

• The novel thylakoid-mimicking microreactor effectively enhances RuBisCO performance for CO2 conversion.
• This artificial photosynthesis system exhibits superior energy conversion efficiency compared to natural photosynthesis.
• The developed technology shows significant potential for mass production, contributing to food supply and carbon neutralization efforts.