Cellulase-lignin interactions: The role of carbohydrate-binding module and pH in non-productive binding

Jenni Rahikainen, James David Evans, Saara Mikander, Anna Kalliola, T. Puranen, Tarja Tamminen, Kaisa Marjamaa, Kristiina Kruus (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

Non-productive cellulase adsorption onto lignin is a major inhibitory mechanism preventing enzymatic hydrolysis of lignocellulosic feedstocks. Therefore, understanding of enzyme–lignin interactions is essential for the development of enzyme mixtures and processes for lignocellulose hydrolysis. We have studied cellulase–lignin interactions using model enzymes, Melanocarpus albomyces Cel45A endoglucanase (MaCel45A) and its fusions with native and mutated carbohydrate-binding modules (CBMs) from Trichoderma reesei Cel7A. Binding of MaCel45A to lignin was dependent on pH in the presence and absence of the CBM; at high pH, less enzyme bound to isolated lignins. Potentiometric titration of the lignin preparations showed that negatively charged groups were present in the lignin samples and that negative charge in the samples was increased with increasing pH. The results suggest that electrostatic interactions contributed to non-productive enzyme adsorption: Reduced enzyme binding at high pH was presumably due to repulsive electrostatic interactions between the enzymes and lignin. The CBM increased binding of MaCel45A to the isolated lignins only at high pH. Hydrophobic interactions are probably involved in CBM binding to lignin, because the same aromatic amino acids that are essential in CBM–cellulose interaction were also shown to contribute to lignin-binding.
Original languageEnglish
Pages (from-to)315-321
Number of pages6
JournalEnzyme and Microbial Technology
Volume53
Issue number5
DOIs
Publication statusPublished - 2013
MoE publication typeA1 Journal article-refereed

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Cellulase
Lignin
Carbohydrates
Enzymes
Coulomb interactions
Static Electricity
Adsorption
Hydrolysis
Aromatic Amino Acids
Trichoderma
Enzymatic hydrolysis
Titration
Hydrophobic and Hydrophilic Interactions
Carboxylic acids
Feedstocks
Amino acids
Fusion reactions

Keywords

  • CBM
  • cellulase
  • electrostatic interaction
  • ligning
  • lignocellulose
  • non-productive binding

Cite this

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title = "Cellulase-lignin interactions: The role of carbohydrate-binding module and pH in non-productive binding",
abstract = "Non-productive cellulase adsorption onto lignin is a major inhibitory mechanism preventing enzymatic hydrolysis of lignocellulosic feedstocks. Therefore, understanding of enzyme–lignin interactions is essential for the development of enzyme mixtures and processes for lignocellulose hydrolysis. We have studied cellulase–lignin interactions using model enzymes, Melanocarpus albomyces Cel45A endoglucanase (MaCel45A) and its fusions with native and mutated carbohydrate-binding modules (CBMs) from Trichoderma reesei Cel7A. Binding of MaCel45A to lignin was dependent on pH in the presence and absence of the CBM; at high pH, less enzyme bound to isolated lignins. Potentiometric titration of the lignin preparations showed that negatively charged groups were present in the lignin samples and that negative charge in the samples was increased with increasing pH. The results suggest that electrostatic interactions contributed to non-productive enzyme adsorption: Reduced enzyme binding at high pH was presumably due to repulsive electrostatic interactions between the enzymes and lignin. The CBM increased binding of MaCel45A to the isolated lignins only at high pH. Hydrophobic interactions are probably involved in CBM binding to lignin, because the same aromatic amino acids that are essential in CBM–cellulose interaction were also shown to contribute to lignin-binding.",
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Cellulase-lignin interactions : The role of carbohydrate-binding module and pH in non-productive binding. / Rahikainen, Jenni; Evans, James David; Mikander, Saara; Kalliola, Anna; Puranen, T.; Tamminen, Tarja; Marjamaa, Kaisa; Kruus, Kristiina (Corresponding Author).

In: Enzyme and Microbial Technology, Vol. 53, No. 5, 2013, p. 315-321.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Cellulase-lignin interactions

T2 - The role of carbohydrate-binding module and pH in non-productive binding

AU - Rahikainen, Jenni

AU - Evans, James David

AU - Mikander, Saara

AU - Kalliola, Anna

AU - Puranen, T.

AU - Tamminen, Tarja

AU - Marjamaa, Kaisa

AU - Kruus, Kristiina

PY - 2013

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N2 - Non-productive cellulase adsorption onto lignin is a major inhibitory mechanism preventing enzymatic hydrolysis of lignocellulosic feedstocks. Therefore, understanding of enzyme–lignin interactions is essential for the development of enzyme mixtures and processes for lignocellulose hydrolysis. We have studied cellulase–lignin interactions using model enzymes, Melanocarpus albomyces Cel45A endoglucanase (MaCel45A) and its fusions with native and mutated carbohydrate-binding modules (CBMs) from Trichoderma reesei Cel7A. Binding of MaCel45A to lignin was dependent on pH in the presence and absence of the CBM; at high pH, less enzyme bound to isolated lignins. Potentiometric titration of the lignin preparations showed that negatively charged groups were present in the lignin samples and that negative charge in the samples was increased with increasing pH. The results suggest that electrostatic interactions contributed to non-productive enzyme adsorption: Reduced enzyme binding at high pH was presumably due to repulsive electrostatic interactions between the enzymes and lignin. The CBM increased binding of MaCel45A to the isolated lignins only at high pH. Hydrophobic interactions are probably involved in CBM binding to lignin, because the same aromatic amino acids that are essential in CBM–cellulose interaction were also shown to contribute to lignin-binding.

AB - Non-productive cellulase adsorption onto lignin is a major inhibitory mechanism preventing enzymatic hydrolysis of lignocellulosic feedstocks. Therefore, understanding of enzyme–lignin interactions is essential for the development of enzyme mixtures and processes for lignocellulose hydrolysis. We have studied cellulase–lignin interactions using model enzymes, Melanocarpus albomyces Cel45A endoglucanase (MaCel45A) and its fusions with native and mutated carbohydrate-binding modules (CBMs) from Trichoderma reesei Cel7A. Binding of MaCel45A to lignin was dependent on pH in the presence and absence of the CBM; at high pH, less enzyme bound to isolated lignins. Potentiometric titration of the lignin preparations showed that negatively charged groups were present in the lignin samples and that negative charge in the samples was increased with increasing pH. The results suggest that electrostatic interactions contributed to non-productive enzyme adsorption: Reduced enzyme binding at high pH was presumably due to repulsive electrostatic interactions between the enzymes and lignin. The CBM increased binding of MaCel45A to the isolated lignins only at high pH. Hydrophobic interactions are probably involved in CBM binding to lignin, because the same aromatic amino acids that are essential in CBM–cellulose interaction were also shown to contribute to lignin-binding.

KW - CBM

KW - cellulase

KW - electrostatic interaction

KW - ligning

KW - lignocellulose

KW - non-productive binding

U2 - 10.1016/j.enzmictec.2013.07.003

DO - 10.1016/j.enzmictec.2013.07.003

M3 - Article

VL - 53

SP - 315

EP - 321

JO - Enzyme and Microbial Technology

JF - Enzyme and Microbial Technology

SN - 0141-0229

IS - 5

ER -