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Esterification degree of fructose laurate exerted by Candida antarctica lipase B in organic solvents

Paper ID Volume ID Publish Year Pages File Format Full-Text
16947 42625 2015 8 PDF Available
Title
Esterification degree of fructose laurate exerted by Candida antarctica lipase B in organic solvents
Abstract

•Lipase (CALB) shows selectivity for esterification degree (DE) of fructose laurate.•High DE product synthesized more effective in methyl ethyl ketone by CALB enzyme.•Conformational changes of CALB controlling high DE selectivity in methyl ethyl ketone.

Sugar esters of fatty acids have many applications as biocompatible and biodegradable emulsifiers, which are determined by their degrees of esterification (DE). Direct esterification of fructose with lauric acid in organic media used commercial immobilized Candida antarctica lipase B (CALB) was investigated for DE. Significant difference of DE was observed between 2-methyl-2-butanol (2M2B) and methyl ethyl ketone (MEK), as di-ester/mono-ester molar ratio of 1.05:1 in 2M2B and 2.79:1 in MEK. Fourier transform infrared (FTIR) spectra showed that the secondary structure of the enzyme binding mono-ester presented distinct difference in 2M2B and MEK. Contents of β-turn and antiparallel β-sheet of CALB in 2M2B were 26.9% and 16.2%, respectively, but 19.1% and 13.2% in MEK. To understand the relationship between the conformational changes and differences of DE, mono-ester and fatty acid were directly employed for synthesis of di-ester. The maximum initial velocity of di-ester synthesis in MEK was 0.59 mmol g (enzyme)−1 h−1, which was 2.19-fold as greater as that in 2M2B, indicating that CALB conformation in MEK was preferred for the synthesis of di-ester. These results demonstrated that the conformation of CALB binding mono-ester affected by organic solvents essentially determined DE.

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Keywords
DE, degree of esterification; 2M2B, 2-methyl-2-butanol; MEK, methyl ethyl ketone; ANOVA, analysis of variance; ATR-FTIR, attenuated total reflectance-Fourier transform infrared; CALB, Candida antarctica lipase B; HLB, hydrophilic lipophilic balance; TLC,
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Esterification degree of fructose laurate exerted by Candida antarctica lipase B in organic solvents
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 69, February 2015, Pages 46–53
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
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Full-text PDF Download
Online Support
Any Questions? feel free to contact us