Cryogel-Immobilized Catalase as a Biocatalyst with Enhanced Stability Against Microplastics.

Area of Science:

• Biomaterials Engineering
• Enzyme Immobilization
• Environmental Remediation

Background:

• Catalase is crucial for reducing oxidative stress but suffers from poor stability.
• Polystyrene microplastics (PS-MPs) pose environmental challenges and can impact enzyme function.
• Developing stable enzyme immobilization matrices is vital for industrial and environmental applications.

Purpose of the Study:

• To synthesize and characterize Poly(HEMA-co-AGE) cryogels as matrices for catalase immobilization.
• To evaluate the enhanced stability and activity of immobilized catalase under stress conditions, including PS-MP contamination.
• To assess the potential of the cryogel system for practical applications like wastewater treatment.

Main Methods:

• Synthesis and characterization of Poly(HEMA-co-AGE) cryogels using FT-IR, SEM, TEM, TGA, and BET.
• Immobilization of catalase onto the cryogel matrix.
• Assessing immobilized catalase activity and stability under varying PS-MP concentrations, temperatures, and time.
• Kinetic analysis and long-term stability/reusability tests.

Main Results:

• The Poly(HEMA-co-AGE) cryogel with 250 µL AGE showed optimal properties, including high immobilization capacity (356.3 mg·g⁻¹).
• Immobilized catalase exhibited enhanced stability and activity in the presence of PS-MPs, across diverse temperatures (4-60 °C) and exposure times (up to 5 h).
• The immobilized enzyme demonstrated improved substrate affinity (Km decreased from 54.9 to 17.1 mM), retained ~80% activity after 70 days at 4 °C, and showed 55% activity after 15 reuse cycles.

Conclusions:

• Poly(HEMA-co-AGE) cryogels provide a robust platform for enhancing catalase stability and reusability.
• The immobilized enzyme system shows promise for applications in microplastic-contaminated environments, such as wastewater treatment and biosensing.
• This work offers a viable solution for enzyme stabilization in challenging industrial and environmental settings.