Restriction of the enzymatic hydrolysis of steam pretreated spruce by lignin and hemicellulose

Anikó Várnai (Corresponding Author), Matti Siika-aho, Liisa Viikari

Research output: Contribution to journalArticleScientificpeer-review

139 Citations (Scopus)

Abstract

The presence of lignin is known to reduce the efficiency of the enzymatic hydrolysis of lignocellulosic raw materials. On the other hand, solubilization of hemicellulose, especially of xylan, is known to enhance the hydrolysis of cellulose. The enzymatic hydrolysis of spruce, recognized among the most challenging lignocellulosic substrates, was studied by commercial and purified enzymes from Trichoderma reesei. Previously, the enzymatic hydrolysis of steam pretreated spruce has been studied mainly by using commercial enzymes and no efforts have been taken to clarify the bottlenecks by using purified enzyme components.

Steam-pretreated spruce was hydrolyzed with a mixture of Celluclast and Novozym 188 to obtain a hydrolysis residue, expectedly containing the most resistant components. The pretreated raw material and the hydrolysis residue were analyzed for the enrichment of structural bottlenecks during the hydrolysis. Lignin was removed from these two materials with chlorite delignification method in order to eliminate the limitations caused by lignin. Avicel was used for comparison as a known model substrate. Mixtures of purified enzymes were used to investigate the hydrolysis of the individual carbohydrates: cellulose, glucomannan and xylan in the substrates. The results reveal that factors limiting the hydrolysis are mainly due to the lignin, and to a minor extent by the lack of accessory enzymes. Removal of lignin doubled the hydrolysis degree of the raw material and the residue, and reached close to 100% of the theoretical within 2 days. The presence of xylan seems to limit the hydrolysability, especially of the delignified substrates. The hydrolysis results also revealed significant hemicellulose impurities in the commonly used cellulose model substrate, making it questionable to use Avicel as a model cellulose substrate for hydrolysis experiments.
Original languageEnglish
Pages (from-to)185-193
Number of pages9
JournalEnzyme and Microbial Technology
Volume46
Issue number3-4
DOIs
Publication statusPublished - 2010
MoE publication typeA1 Journal article-refereed

Fingerprint

Enzymatic hydrolysis
Lignin
Steam
Hydrolysis
Cellulose
Enzymes
Xylans
Substrates
Raw materials
hemicellulose
Delignification
Accessories
Carbohydrates
Trichoderma
Impurities

Keywords

  • cellulose
  • lignocellulose
  • spruce
  • enzymatic hydrolysis
  • cellulase
  • xylanase
  • delignification
  • hydrolysis limitation

Cite this

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title = "Restriction of the enzymatic hydrolysis of steam pretreated spruce by lignin and hemicellulose",
abstract = "The presence of lignin is known to reduce the efficiency of the enzymatic hydrolysis of lignocellulosic raw materials. On the other hand, solubilization of hemicellulose, especially of xylan, is known to enhance the hydrolysis of cellulose. The enzymatic hydrolysis of spruce, recognized among the most challenging lignocellulosic substrates, was studied by commercial and purified enzymes from Trichoderma reesei. Previously, the enzymatic hydrolysis of steam pretreated spruce has been studied mainly by using commercial enzymes and no efforts have been taken to clarify the bottlenecks by using purified enzyme components.Steam-pretreated spruce was hydrolyzed with a mixture of Celluclast and Novozym 188 to obtain a hydrolysis residue, expectedly containing the most resistant components. The pretreated raw material and the hydrolysis residue were analyzed for the enrichment of structural bottlenecks during the hydrolysis. Lignin was removed from these two materials with chlorite delignification method in order to eliminate the limitations caused by lignin. Avicel was used for comparison as a known model substrate. Mixtures of purified enzymes were used to investigate the hydrolysis of the individual carbohydrates: cellulose, glucomannan and xylan in the substrates. The results reveal that factors limiting the hydrolysis are mainly due to the lignin, and to a minor extent by the lack of accessory enzymes. Removal of lignin doubled the hydrolysis degree of the raw material and the residue, and reached close to 100{\%} of the theoretical within 2 days. The presence of xylan seems to limit the hydrolysability, especially of the delignified substrates. The hydrolysis results also revealed significant hemicellulose impurities in the commonly used cellulose model substrate, making it questionable to use Avicel as a model cellulose substrate for hydrolysis experiments.",
keywords = "cellulose, lignocellulose, spruce, enzymatic hydrolysis, cellulase, xylanase, delignification, hydrolysis limitation",
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Restriction of the enzymatic hydrolysis of steam pretreated spruce by lignin and hemicellulose. / Várnai, Anikó (Corresponding Author); Siika-aho, Matti; Viikari, Liisa.

In: Enzyme and Microbial Technology, Vol. 46, No. 3-4, 2010, p. 185-193.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Restriction of the enzymatic hydrolysis of steam pretreated spruce by lignin and hemicellulose

AU - Várnai, Anikó

AU - Siika-aho, Matti

AU - Viikari, Liisa

PY - 2010

Y1 - 2010

N2 - The presence of lignin is known to reduce the efficiency of the enzymatic hydrolysis of lignocellulosic raw materials. On the other hand, solubilization of hemicellulose, especially of xylan, is known to enhance the hydrolysis of cellulose. The enzymatic hydrolysis of spruce, recognized among the most challenging lignocellulosic substrates, was studied by commercial and purified enzymes from Trichoderma reesei. Previously, the enzymatic hydrolysis of steam pretreated spruce has been studied mainly by using commercial enzymes and no efforts have been taken to clarify the bottlenecks by using purified enzyme components.Steam-pretreated spruce was hydrolyzed with a mixture of Celluclast and Novozym 188 to obtain a hydrolysis residue, expectedly containing the most resistant components. The pretreated raw material and the hydrolysis residue were analyzed for the enrichment of structural bottlenecks during the hydrolysis. Lignin was removed from these two materials with chlorite delignification method in order to eliminate the limitations caused by lignin. Avicel was used for comparison as a known model substrate. Mixtures of purified enzymes were used to investigate the hydrolysis of the individual carbohydrates: cellulose, glucomannan and xylan in the substrates. The results reveal that factors limiting the hydrolysis are mainly due to the lignin, and to a minor extent by the lack of accessory enzymes. Removal of lignin doubled the hydrolysis degree of the raw material and the residue, and reached close to 100% of the theoretical within 2 days. The presence of xylan seems to limit the hydrolysability, especially of the delignified substrates. The hydrolysis results also revealed significant hemicellulose impurities in the commonly used cellulose model substrate, making it questionable to use Avicel as a model cellulose substrate for hydrolysis experiments.

AB - The presence of lignin is known to reduce the efficiency of the enzymatic hydrolysis of lignocellulosic raw materials. On the other hand, solubilization of hemicellulose, especially of xylan, is known to enhance the hydrolysis of cellulose. The enzymatic hydrolysis of spruce, recognized among the most challenging lignocellulosic substrates, was studied by commercial and purified enzymes from Trichoderma reesei. Previously, the enzymatic hydrolysis of steam pretreated spruce has been studied mainly by using commercial enzymes and no efforts have been taken to clarify the bottlenecks by using purified enzyme components.Steam-pretreated spruce was hydrolyzed with a mixture of Celluclast and Novozym 188 to obtain a hydrolysis residue, expectedly containing the most resistant components. The pretreated raw material and the hydrolysis residue were analyzed for the enrichment of structural bottlenecks during the hydrolysis. Lignin was removed from these two materials with chlorite delignification method in order to eliminate the limitations caused by lignin. Avicel was used for comparison as a known model substrate. Mixtures of purified enzymes were used to investigate the hydrolysis of the individual carbohydrates: cellulose, glucomannan and xylan in the substrates. The results reveal that factors limiting the hydrolysis are mainly due to the lignin, and to a minor extent by the lack of accessory enzymes. Removal of lignin doubled the hydrolysis degree of the raw material and the residue, and reached close to 100% of the theoretical within 2 days. The presence of xylan seems to limit the hydrolysability, especially of the delignified substrates. The hydrolysis results also revealed significant hemicellulose impurities in the commonly used cellulose model substrate, making it questionable to use Avicel as a model cellulose substrate for hydrolysis experiments.

KW - cellulose

KW - lignocellulose

KW - spruce

KW - enzymatic hydrolysis

KW - cellulase

KW - xylanase

KW - delignification

KW - hydrolysis limitation

U2 - 10.1016/j.enzmictec.2009.12.013

DO - 10.1016/j.enzmictec.2009.12.013

M3 - Article

VL - 46

SP - 185

EP - 193

JO - Enzyme and Microbial Technology

JF - Enzyme and Microbial Technology

SN - 0141-0229

IS - 3-4

ER -