Optimization of lipase-catalyzed glucose ester synthesis in ionic liquids

Area of Science:

• Biocatalysis
• Green Chemistry
• Enzyme Engineering

Background:

• Ionic liquids (ILs) offer unique reaction media for enzymatic synthesis.
• Lipase-catalyzed esterification of glucose is a key step in producing sugar esters.
• Optimizing reaction conditions is crucial for enzyme stability and product yield.

Purpose of the Study:

• To investigate lipase-catalyzed esterification of glucose with fatty acids in ionic liquid mixtures.
• To determine the optimal IL mixture ratio, substrate ratio, lipase content, and temperature.
• To evaluate the reusability of lipase and ionic liquids.

Main Methods:

• Utilized supersaturated glucose solutions for esterification.
• Screened various mixtures of 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([Bmim][TfO]) and 1-methyl-3-octylimidazolium bis[(trifluoromethyl)-sulfonyl]amide ([Omim][Tf(2)N]).
• Assessed the impact of reaction parameters on enzyme activity and stability using Novozym 435.

Main Results:

• Highest sugar ester yield was achieved with a 9:1 volume ratio of [Bmim][TfO] to [Omim][Tf(2)N].
• Optimal stability and activity of Novozym 435 occurred in a 1:1 volume ratio of the ILs.
• Lipase and ILs were successfully reused, retaining 78% of initial activity after five cycles.

Conclusions:

• The study successfully optimized lipase-catalyzed glucose esterification in IL mixtures.
• Demonstrated the potential for efficient and reusable biocatalytic systems for sugar ester production.
• Highlights the importance of IL selection and ratio for enzyme performance and process sustainability.