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Use of Lecitase-Ultra immobilized on styrene-divinylbenzene beads as catalyst of esterification reactions: Effects of ultrasounds

Paper ID Volume ID Publish Year Pages File Format Full-Text
53763 46983 2015 6 PDF Available
Title
Use of Lecitase-Ultra immobilized on styrene-divinylbenzene beads as catalyst of esterification reactions: Effects of ultrasounds
Abstract

•Lecitase-Ultra immobilized on MCI is useful for many esterification reactions.•Ultrasound agitation improves enzyme reaction rate and the use of higher substrate concentrations.•Molecular sieves improve operational stability.

In this work it was evaluated for the first time, the ester synthesis catalyzed by the phospholipase Lecitase-Ultra immobilized styrene-divinylbenzene beads (MCI-Lecitase), comparing the mechanical stirring and the ultrasonic energy. It was studied the specificity of the enzyme using carboxylic acids from C4 to C18, as well as the effects of alcohol chain, organic solvents, biocatalyst content, reaction temperature and substrate concentration. Caprylic and myristic acids were those with the highest reaction rates and yields, using ethanol as substrate. The shorter the alcohol chain, the higher the enzyme activity. Regarding the secondary alcohols, while MCI-Lecitase had no activity versus isopropanol, using 2-pentanol the activity was similar to that with 1-pentanol. Comparing the agitation systems, MCI-Lecitase presented an initial reaction rate more than 2-times higher in the ultrasound-assisted reaction than under traditional mechanical stirring. Moreover, under ultrasonic energy the maximum rate was achieved using 0.5 M of substrates, while under mechanical stirring the maximum enzyme activity was reached at 0.3 M of substrates. Concerning the operational stability, MCI-Lecitase was quite unstable, losing its activity after 6 reaction cycles. By adding molecular sieves in the reaction medium, MCI-Lecitase retained 30% of its initial activity after 6 cycles.

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Keywords
Lecitase-Ultra; Enzyme immobilization; Styrene divinyl-benzene; Esterification; Ultrasound
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Use of Lecitase-Ultra immobilized on styrene-divinylbenzene beads as catalyst of esterification reactions: Effects of ultrasounds
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 255, 15 October 2015, Pages 27–32
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us