Beyond CO₂ Storage: Enzyme-Amyloid Fibril Catalytic Hybrids for Long Cascade Reactions Converting CO₂ into Fructose

Area of Science:

• Biochemistry
• Biomaterials Science
• Synthetic Biology

Background:

• Enzyme immobilization enhances stability and reusability but coimmobilizing multiple enzymes for cascade reactions remains challenging.
• Developing stable and efficient platforms for multi-enzyme systems is crucial for biocatalysis and synthetic photosynthesis.

Purpose of the Study:

• To present a facile enzyme immobilization platform using β-lactoglobulin amyloid fibril hydrogels.
• To demonstrate the effectiveness of this platform for stabilizing enzymes involved in cascade reactions, mimicking photosynthesis.

Main Methods:

• Immobilization of RuBisCO (AFR*) and seven Calvin Cycle enzymes (AF7E) within β-lactoglobulin amyloid hydrogels.
• Assessing enzyme activity, stability, and CO2 fixation efficiency.
• Characterizing biodegradability using pepsin, atomic force microscopy, and circular dichroism spectroscopy.

Main Results:

• Immobilization efficiency exceeded 95% for both AFR* and AF7E hydrogels, with excellent enzyme activity and stability.
• The AF7E hydrogel successfully catalyzed CO2 fixation into 3-phosphoglycerate (3-PGA) and subsequent Calvin Cycle reactions.
• The amyloid hydrogel proved to be completely biodegradable by pepsin.

Conclusions:

• The enzyme-amyloid hybrid hydrogel platform is biocompatible, sustainable, and scalable.
• This system offers a promising general template for developing multienzymatic catalytic platforms, particularly for artificial photosynthesis.