Effect of temperature on lignin-derived inhibition studied with three structurally different cellobiohydrolases

Rahikainen, Jenni; Moilanen, Ulla; Nurmi-Rantala, Susanna; Lappas, Angelos A.; Koivula, Anu; Viikari, Liisa; Kruus, Kristiina

doi:10.1016/j.biortech.2013.07.069

Cited by 51 publications

(46 citation statements)

References 32 publications

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“…This suggested the possibility of partial irreversible binding on L‐HPWS, that is, the enzymes are first bound reversibly, which is then followed by further interactions leading to irreversible binding. This is in line with the idea of protein unfolding taking place after binding on lignin (Rahikainen et al, ; Rahikainen, Moilanen et al, ; Sammond et al, ).…”

Section: Resultssupporting

confidence: 88%

“…This indicated lower binding affinity of cellulases on L-HPWS than L-HPS, which is in accordance with the high desorption on L-HPWS after dilution (Figure 3). The difference in affinity can offer an explanation on the previous observations where L-HPS was found to retard the enzymatic hydrolysis of model cellulose more than L-HPWS (Kellock et al, 2017;Rahikainen, Moilanen et al, 2013).…”

Section: ← → ⎯⎯⎯mentioning

confidence: 99%

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Cellulases adsorb reversibly on biomass lignin

Djajadi

Pihlajaniemi

Rahikainen

et al. 2018

Biotech & Bioengineering

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Adsorption of cellulases onto lignin is considered a major factor in retarding enzymatic cellulose degradation of lignocellulosic biomass. However, the adsorption mechanisms and kinetics are not well understood for individual types of cellulases. This study examines the binding affinity, kinetics of adsorption, and competition of four monocomponent cellulases of Trichoderma reesei during adsorption onto lignin. TrCel7A, TrCel6A, TrCel7B, and TrCel5A were radiolabeled for adsorption experiments on lignin‐rich residues (LRRs) isolated from hydrothermally pretreated spruce (L‐HPS) and wheat straw (L‐HPWS), respectively. On the basis of adsorption isotherms fitted to the Langmuir model, the ranking of binding affinities was TrCel5A > TrCel6A > TrCel7B > TrCel7A on both types of LRRs. The enzymes had a higher affinity to the L‐HPS than to the L‐HPWS. Adsorption experiments with dilution after 1 and 24 hr and kinetic modeling were performed to quantify any irreversible binding over time. Models with reversible binding parameters fitted well and can explain the results obtained. The adsorption constants obtained from the reversible models agreed with the fitted Langmuir isotherms and suggested that reversible adsorption–desorption existed at equilibrium. Competitive binding experiments showed that individual types of cellulases competed for binding sites on the lignin and the adsorption data fitted the Langmuir adsorption model. Overall, the data strongly indicate that the adsorption of cellulases onto lignin is reversible and the findings have implications for the development of more efficient cellulose degrading enzymes.

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Section: Resultssupporting

confidence: 88%

Section: ← → ⎯⎯⎯mentioning

confidence: 99%

Cellulases adsorb reversibly on biomass lignin

Djajadi

Pihlajaniemi

Rahikainen

et al. 2018

Biotech & Bioengineering

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“…In control experiments without inhibitor compounds, the pH of the assay mixture remained at pH 5.2, but dropped to 4.9 or 4.63 when acetic or formic acid was added at 25%, and to 4.37 or 3.69 in the presence of 100% of the inhibitors, respectively. The loss of BGL1 activity upon the addition of weak acids and of CBH1 activity with increased acetic acid concentrations can partially be attributed to the drop in pH which has been shown to change the surface charges of the enzyme and enhance non-specific binding [33].…”

Section: Discussionmentioning

confidence: 99%

Lignocellulosic hydrolysate inhibitors selectively inhibit/deactivate cellulase performance

Mhlongo

Haan

Viljoen-Bloom

et al. 2015

Enzyme and Microbial Technology

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“…The advantage of the CBM-lacking enzymes is that a significantly higher share can be recovered non-bound and active after the hydrolysis [18], as compared to the CBM-containing enzymes, of which a higher share remains bound especially to lignin containing substrates. During recycling, loss of enzymes occurs due to unproductive binding and denaturation of enzymes [22,23]. …”

Section: Introductionmentioning

confidence: 99%

Cellulases without carbohydrate-binding modules in high consistency ethanol production process

Pakarinen

Haven

Djajadi

et al. 2014

Biotechnol Biofuels

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BackgroundEnzymes still comprise a major part of ethanol production costs from lignocellulose raw materials. Irreversible binding of enzymes to the residual substrate prevents their reuse and no efficient methods for recycling of enzymes have so far been presented. Cellulases without a carbohydrate-binding module (CBM) have been found to act efficiently at high substrate consistencies and to remain non-bound after the hydrolysis.ResultsHigh hydrolysis yields could be obtained with thermostable enzymes of Thermoascus aurantiacus containing only two main cellulases: cellobiohydrolase I (CBH I), Cel7A and endoglucanase II (EG II), Cel5A. The yields were decreased by only about 10% when using these cellulases without CBM. A major part of enzymes lacking CBM was non-bound during the most active stage of hydrolysis and in spite of this, produced high sugar yields. Complementation of the two cellulases lacking CBM with CBH II (CtCel6A) improved the hydrolysis. Cellulases without CBM were more sensitive during exposure to high ethanol concentration than the enzymes containing CBM. Enzymes lacking CBM could be efficiently reused leading to a sugar yield of 90% of that with fresh enzymes. The applicability of cellulases without CBM was confirmed under industrial ethanol production conditions at high (25% dry matter (DM)) consistency.ConclusionsThe results clearly show that cellulases without CBM can be successfully used in the hydrolysis of lignocellulose at high consistency, and that this approach could provide new means for better recyclability of enzymes. This paper provides new insight into the efficient action of CBM-lacking cellulases. The relationship of binding and action of cellulases without CBM at high DM consistency should, however, be studied in more detail.

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Effect of temperature on lignin-derived inhibition studied with three structurally different cellobiohydrolases

Cited by 51 publications

References 32 publications

Cellulases adsorb reversibly on biomass lignin

Cellulases adsorb reversibly on biomass lignin

Lignocellulosic hydrolysate inhibitors selectively inhibit/deactivate cellulase performance

Cellulases without carbohydrate-binding modules in high consistency ethanol production process

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