Development of Novel Catalytic Deep Eutectic Solvent for Esterification and Elucidation of Dynamic...

Area of Science:

• Biocatalysis
• Green Chemistry
• Enzyme Engineering

Background:

• Biocatalytic ester synthesis faces limitations due to substrate polarity, toxic solvents, and costly activated acyl donors.
• Industrial expansion of ester synthesis is hindered by these challenges, necessitating innovative solutions.

Purpose of the Study:

• To develop a novel catalytic deep eutectic solvent (CDES) system for efficient and sustainable biocatalytic ester synthesis.
• To address challenges associated with substrate polarity and enzyme stability in esterification reactions.
• To demonstrate the broad applicability and industrial potential of the developed CS-NMI system.

Main Methods:

• Development of a novel catalytic deep eutectic solvent (CDES) system composed of cyclohexanone, stearic acid, and N-methylimidazole (CS-NMI).
• Utilized sucrose stearate synthesis as a model reaction for extreme esterification.
• Employed an in-house Candida antarctica lipase B (CALB) mutant (X1) for enhanced enzymatic performance.
• Conducted molecular dynamics (MD) simulations to elucidate the solvent-enzyme-substrate interactions.

Main Results:

• Achieved 98.2±0.7% conversion for sucrose stearate synthesis, with 90.5±0.8% conversion after 10 lipase reuses.
• Demonstrated enzymatic esterification of sucrose with stearic acid, yielding 42.8±0.5% conversion.
• Synthesized vitamin E succinate, menthyl acetate, and propyl laurate with over 85.0% yields.
• The CALB mutant X1 achieved 98.1±1.3% conversion for sucrose stearate synthesis after scale-up and immobilization.
• MD simulations revealed CS-NMI stabilizes enzyme conformation and enhances mass transfer.

Conclusions:

• The CS-NMI CDES system provides a sustainable and universal strategy for complex biocatalytic esterification.
• The developed system effectively overcomes substrate polarity and solvent limitations, enhancing enzyme stability and reusability.
• This approach holds significant potential for industrial applications in green ester synthesis.