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Influence of operation conditions on laccase-mediator removal of sterols from eucalypt pulp

Paper ID Volume ID Publish Year Pages File Format Full-Text
35342 45087 2009 7 PDF Available
Title
Influence of operation conditions on laccase-mediator removal of sterols from eucalypt pulp
Abstract

The way how sterols, the main lipophilic compounds present in eucalypt kraft pulp, are eliminated by an enzymatic stage using the laccase-mediator system was evaluated. With this purpose laccase-mediator stage (L) was applied on an Eucalyptus globulus pulp under different operation conditions following a three-variable (laccase dose, mediator dose and reaction time) sequential statistical plan, to optimise the removal of sterols. The decrease in pulp sterol content during the enzymatic treatment was related to the decrease in kappa number and to brightness increase, as well as with the increase in some oxidation products of sitosterol (namely 7-oxositosterol and stigmasta-3,5-dien-7-one). The increase in reaction time from 1 to 5 h strongly reduced the sterol content, while no more sterols were eliminated during the 5–7 h period. Increasing the laccase dose from 1 to 20 U g−1 of pulp produced a high reduction in pulp sterols, whereas the increase in mediator (1-hydroxybenzotriazole) dose (from 0.5 to 2.5% of pulp weight) had only a slight influence in removing sterols. Therefore, at 16 U g−1 laccase dose, 0.5% mediator dose, 4 h of reaction, practically all the sterols were removed. Finally, it was demonstrated that sterols were more sensitive to a L stage (practically 100% of sterols were eliminated) than to a chlorine dioxide stage (54% of sterols eliminated).

Keywords
Eucalypt; 1-Hydroxybenzotriazole (HBT); Laccase; Modelling; Sterols; Pitch
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Influence of operation conditions on laccase-mediator removal of sterols from eucalypt pulp
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Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 44, Issue 9, September 2009, Pages 1032–1038
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
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us