Using ionic liquids in whole-cell biocatalysis for the nucleoside acylation

Area of Science:

• Biocatalysis
• Green Chemistry
• Organic Synthesis

Background:

• Biocatalysis offers selective, mild, and eco-friendly alternatives to traditional chemical synthesis.
• Organic solvents in biocatalysis present challenges like toxicity and reduced enzyme activity.
• Ionic liquids (ILs) are emerging as promising, environmentally friendly solvents for nonaqueous biocatalysis.

Purpose of the Study:

• To develop novel ionic liquid (IL)-based reaction systems for synthesizing long-chain nucleoside esters.
• To investigate the impact of various ILs on the efficiency and selectivity of whole-cell biocatalysis.
• To understand the mechanism by which ILs influence cell morphology and substrate-enzyme interactions.

Main Methods:

• Utilized whole cells of Pseudomonas fluorescens for biocatalytic synthesis.
• Screened various ionic liquids and co-solvents (e.g., THF) to optimize reaction conditions.
• Employed Scanning Electron Microscopy (SEM) to analyze changes in cell surface morphology.

Main Results:

• The IL 10% [BMI][PF6]/THF significantly enhanced the synthesis of arabinocytosine laurate.
• Achieved high reaction efficiency (2.34 mmol/L·h), product yield (81.1%), and >99% 5'-regioselectivity.
• SEM analysis indicated ILs improve cell envelope permeability, facilitating substrate mass transfer.

Conclusions:

• Ionic liquids show significant potential as reaction media for highly efficient and regioselective whole-cell catalysis.
• ILs can positively modulate biocatalyst performance by altering cell surface properties.
• This study highlights a sustainable and effective method for nucleoside ester synthesis.