Experiences of kraft lignin functionalization by enzymatic and chemical oxidation

Anna Kalliola (Corresponding Author), Martta Asikainen, Riku Talja, Tarja Tamminen

Research output: Contribution to journalArticleScientificpeer-review

6 Citations (Scopus)

Abstract

Linear hydrophilic derivatives are expected to soften lignin and improve its utilization in composite applications. Oxidation by means of laccase in the presence of oxygen was employed in an attempt to functionalize commercial kraft lignin by vanillic acid-PEG ester and ether derivatives. Thielavia arenaria and Melanocarpus albomyces laccases at pH 6 and 8 were used. According to O2 consumption and the increase in molar mass, the tested laccases were active toward the lignin and the vanillic acid derivatives and also formed corresponding phenoxyl radicals. However, homogenous polymerization instead of cross-coupling and functionalization took place. As an alternative, lignin functionalization by the ester derivative by chemical oxidation under alkali-O2 conditions was also tested. Efficient lignin polymerization was observed. However, functionalization was not detected. Interestingly, a clear decrease in lignin glass transition temperature was obtained by an isolation procedure that included freeze-drying. This suggests that functionalization may not be necessary to induce the desired softening effect.
Original languageEnglish
Pages (from-to)7336-7351
JournalBioResources
Volume9
Issue number4
DOIs
Publication statusPublished - 2014
MoE publication typeA1 Journal article-refereed

Fingerprint

Lignin
lignin
Laccase
oxidation
Oxidation
Vanillic Acid
Derivatives
Esters
polymerization
ester
Polymerization
Molar mass
freeze drying
Alkalies
Acids
Ether
acid
Polyethylene glycols
softening
Drying

Keywords

  • kraft lignin
  • vanillic acid
  • polyethylene glycol
  • composite
  • glass transition temperature
  • laccase
  • oxygen
  • oxidation

Cite this

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title = "Experiences of kraft lignin functionalization by enzymatic and chemical oxidation",
abstract = "Linear hydrophilic derivatives are expected to soften lignin and improve its utilization in composite applications. Oxidation by means of laccase in the presence of oxygen was employed in an attempt to functionalize commercial kraft lignin by vanillic acid-PEG ester and ether derivatives. Thielavia arenaria and Melanocarpus albomyces laccases at pH 6 and 8 were used. According to O2 consumption and the increase in molar mass, the tested laccases were active toward the lignin and the vanillic acid derivatives and also formed corresponding phenoxyl radicals. However, homogenous polymerization instead of cross-coupling and functionalization took place. As an alternative, lignin functionalization by the ester derivative by chemical oxidation under alkali-O2 conditions was also tested. Efficient lignin polymerization was observed. However, functionalization was not detected. Interestingly, a clear decrease in lignin glass transition temperature was obtained by an isolation procedure that included freeze-drying. This suggests that functionalization may not be necessary to induce the desired softening effect.",
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author = "Anna Kalliola and Martta Asikainen and Riku Talja and Tarja Tamminen",
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Experiences of kraft lignin functionalization by enzymatic and chemical oxidation. / Kalliola, Anna (Corresponding Author); Asikainen, Martta; Talja, Riku; Tamminen, Tarja.

In: BioResources, Vol. 9, No. 4, 2014, p. 7336-7351.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Experiences of kraft lignin functionalization by enzymatic and chemical oxidation

AU - Kalliola, Anna

AU - Asikainen, Martta

AU - Talja, Riku

AU - Tamminen, Tarja

PY - 2014

Y1 - 2014

N2 - Linear hydrophilic derivatives are expected to soften lignin and improve its utilization in composite applications. Oxidation by means of laccase in the presence of oxygen was employed in an attempt to functionalize commercial kraft lignin by vanillic acid-PEG ester and ether derivatives. Thielavia arenaria and Melanocarpus albomyces laccases at pH 6 and 8 were used. According to O2 consumption and the increase in molar mass, the tested laccases were active toward the lignin and the vanillic acid derivatives and also formed corresponding phenoxyl radicals. However, homogenous polymerization instead of cross-coupling and functionalization took place. As an alternative, lignin functionalization by the ester derivative by chemical oxidation under alkali-O2 conditions was also tested. Efficient lignin polymerization was observed. However, functionalization was not detected. Interestingly, a clear decrease in lignin glass transition temperature was obtained by an isolation procedure that included freeze-drying. This suggests that functionalization may not be necessary to induce the desired softening effect.

AB - Linear hydrophilic derivatives are expected to soften lignin and improve its utilization in composite applications. Oxidation by means of laccase in the presence of oxygen was employed in an attempt to functionalize commercial kraft lignin by vanillic acid-PEG ester and ether derivatives. Thielavia arenaria and Melanocarpus albomyces laccases at pH 6 and 8 were used. According to O2 consumption and the increase in molar mass, the tested laccases were active toward the lignin and the vanillic acid derivatives and also formed corresponding phenoxyl radicals. However, homogenous polymerization instead of cross-coupling and functionalization took place. As an alternative, lignin functionalization by the ester derivative by chemical oxidation under alkali-O2 conditions was also tested. Efficient lignin polymerization was observed. However, functionalization was not detected. Interestingly, a clear decrease in lignin glass transition temperature was obtained by an isolation procedure that included freeze-drying. This suggests that functionalization may not be necessary to induce the desired softening effect.

KW - kraft lignin

KW - vanillic acid

KW - polyethylene glycol

KW - composite

KW - glass transition temperature

KW - laccase

KW - oxygen

KW - oxidation

U2 - 10.15376/biores.9.4.7336-7351

DO - 10.15376/biores.9.4.7336-7351

M3 - Article

VL - 9

SP - 7336

EP - 7351

JO - BioResources

JF - BioResources

SN - 1930-2126

IS - 4

ER -