Continuous Reusability using Immobilized HasApf in Chemoenzymatic Deracemization: A New Heterogeneous Enzyme...

Area of Science:

• Biocatalysis and Enzyme Immobilization
• Organic Synthesis and Asymmetric Oxidation
• Spectroscopy and Analytical Chemistry

Background:

• Heme acquisition system A (HasA) is a novel reactive active species with potential catalytic applications.
• Enzyme immobilization is crucial for enhancing stability, reusability, and industrial applicability of biocatalysts.
• Asymmetric oxidation of alcohols is a key transformation in synthesizing chiral compounds, including pharmaceuticals like naproxen.

Purpose of the Study:

• To immobilize HasA onto porous ceramic particles (ImHApf) and characterize its properties using Fourier transform infrared spectroscopy (FTIR).
• To evaluate the catalytic efficiency of ImHApf in the asymmetric oxidation of a naproxen precursor and other sec-alcohols.
• To demonstrate the potential of HasA immobilization for developing sustainable and environmentally friendly industrial processes.

Main Methods:

• Immobilization of HasA onto porous ceramic particles.
• Characterization of ImHApf using FTIR spectroscopy (1750-1450 cm⁻¹ range).
• Asymmetric oxidation reactions of various racemic alcohols using ImHApf under optimized conditions (glycine-NaOH buffer, 40 °C, absence of NAD(P)).

Main Results:

• Successful construction of a calibration curve for ImHApf using FTIR.
• Achieved >99% enantiomeric excess and >90% chemical yield in the desymmetrization of a naproxen precursor ketone.
• Demonstrated high catalytic activity (0.74 ± 0.03 mU/(mg·min)), turnover number (~2 × 10⁶), and reusability of ImHApf in organic solvents.
• Confirmed the ability of ImHApf to produce single stereoisomers from other racemic sec-alcohols.

Conclusions:

• HasA immobilization on porous ceramic particles (ImHApf) provides a robust and efficient biocatalyst for asymmetric oxidation.
• The ImHApf system exhibits excellent catalytic performance, stability, and reusability, making it suitable for industrial applications.
• HasA immobilization represents a significant advancement towards sustainable and green chemistry in industrial synthesis.