Comparative study on enzymatic digestibility of acid-pretreated poplar and larch based on a comprehensive analysis of the lignin-derived recalcitrance

Jia, Yuan; Yang, Chundong; Shen, Buzhen; Ling, Zhe; Huang, Caoxing; Li, Xin; Lai, Chenhuan; Yong, Qiang

doi:10.1016/j.biortech.2020.124225

Cited by 69 publications

(21 citation statements)

References 35 publications

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“…In sum, BSA can increase the sugar conversion rate of lignocellulosic biomass in two aspects, one is increased enzymatic activity induced by enzyme stabilization; the other is exhibited in nonspeci c adsorption on residual lignin to occupy the binding sites for cellulase. It was found that with the increase of enzyme load, the improvement of enzymatic hydrolysis effect by adding BSA gradually decreased [22]. It supports the action mechanism brought up by us.…”

Section: Proposed Interaction Mechanismssupporting

confidence: 81%

“…The cellulase loading was 20 FPU/g glucan. The addition amount of LS, PEG and BSA was 0.2 g/g, g/L and 5 g/L, respectively, based on the optimal dosage in literature [11,22,41]. After enzymatic hydrolysis, the hydrolysate was boiled for 10 min to inactivate cellulase.…”

Section: Enzymatic Hydrolysis Experimentsmentioning

confidence: 99%

“…Some researchers believe that in addition to preventing the non-productive adsorption of cellulase by lignin, BSA can also reduce the inactivation of exoglycanase, thereby improving the hydrolysis of microcrystalline cellulose [21]. Jia et al [22] compared the effects of adding BSA on the lignocellulose conversion rate of acid-pretreated poplar wood, ethanolwashing acid-pretreated poplar wood, and deligni ed acid-pretreated poplar wood and they found that BSA acts as a synergistic agent by coating the substrate lignin, thereby blocking the binding site of the substrate lignin.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of the Interaction Modes Between Cellulase and Bovine Serum Albumin /Lignosulfonate /Polyethylene Glycol in Promoting Lignocellulose Saccharification

Wang

Lan

Guo

et al. 2021

Preprint

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Background: Bovine serum albumin (BSA), polyethylene glycol (PEG) and lignosulfonate (LS) have been extensively employed as synergistic agents in lignocellulose saccharification, albeit it has not been fully understood how they interact with enzymes from the perspectives of molecular interactions. Herein, we attempted to unveil the promotion mechanisms of BSA, PEG and LS for lignocellulose saccharification from the perspective of their respective interaction with cellulase using Quartz Crystal Microbalance with Dissipation monitoring (QCM-D), Surface Plasmon Resonance (SPR), and Small Angle X-ray Scattering (SAXS) to investigate their respective interaction and the complex formation. In the meanwhile, we compared the effects of adding these additives into the enzymatic hydrolysis of pure cellulose (Avicel) and green liquor-pretreated lignocellulose (GL).Results: The results showed that BSA and LS could bind to cellulase to form complexes, whereas PEG did not. However, PEG had a high affinity to lignin or lignin derivatives. In term for Avicel and GL substrates, the results showed that BSA and PEG promoted the enzymatic hydrolysis of both substrates, while LS had a promoting effect for GL only and inhibited some extent for Avicel. Conclusions: This study showed that synergistic agents of LS, BSA, and PEG have different interaction modes with cellulase. BSA and LS form complexes with cellulase and the formed complexes prevent from nonproductive binding by residue lignin; whereas PEG prevents from nonproductive binding by forming a thin layer on residue lignin which actually serve as steric hindrance. This investigation will help us to understand the sophisticated interactions among the components in the complicated enzymatic system, especially the interactions between enzymes and synergistic agents. It will be helpful in the design and utilization of synergistic additives in the lignocellulose biorefinery process as well.

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Section: Proposed Interaction Mechanismssupporting

confidence: 81%

Section: Enzymatic Hydrolysis Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Comparison of the Interaction Modes Between Cellulase and Bovine Serum Albumin /Lignosulfonate /Polyethylene Glycol in Promoting Lignocellulose Saccharification

Wang

Lan

Guo

et al. 2021

Preprint

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“…Huang et al [ 34 ] also reported that substrates with higher hydrophobicities induced more of nonproductive binding by cellulase, thereby reducing the yield for enzymatic hydrolysis. In a recent study, Jia et al [ 35 ] also pointed out that ethanol removal of surface lignin from acid-pretreated poplar constituted a potential mechanism for the negative effects on enzymatic digestibility. Cellulase mainly consists of cellobiohydrolase I (CBH I or Cel7A), which is negatively charged during enzymatic hydrolysis.…”

Section: Resultsmentioning

confidence: 99%

Understanding the effects of different residual lignin fractions in acid-pretreated bamboo residues on its enzymatic digestibility

Lin

Yang

Zheng

et al. 2021

Biotechnol Biofuels

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Background During the dilute acid pretreatment process, the resulting pseudo-lignin and lignin droplets deposited on the surface of lignocellulose and inhibit the enzymatic digestibility of cellulose in lignocellulose. However, how these lignins interact with cellulase enzymes and then affect enzymatic hydrolysis is still unknown. In this work, different fractions of surface lignin (SL) obtained from dilute acid-pretreated bamboo residues (DAP-BR) were extracted by various organic reagents and the residual lignin in extracted DAP-BR was obtained by the milled wood lignin (MWL) method. All of the lignin fractions obtained from DAP-BR were used to investigate the mechanism for interaction between lignin and cellulase using surface plasmon resonance (SPR) technology to understand how they affect enzymatic hydrolysis Results The results showed that removing surface lignin significantly decreased the yield for enzymatic hydrolysis DAP-BR from 36.5% to 18.6%. The addition of MWL samples to Avicel inhibited its enzymatic hydrolysis, while different SL samples showed slight increases in enzymatic digestibility. Due to the higher molecular weight and hydrophobicity of MWL samples versus SL samples, a stronger affinity for MWL (KD = 6.8–24.7 nM) was found versus that of SL (KD = 39.4–52.6 nM) by SPR analysis. The affinity constants of all tested lignins exhibited good correlations (r > 0.6) with the effects on enzymatic digestibility of extracted DAP-BR and Avicel. Conclusions This work revealed that the surface lignin on DAP-BR is necessary for maintaining enzyme digestibility levels, and its removal has a negative impact on substrate digestibility.

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“…Cellulose content was calculated based on the glucose concentration, while hemicellulose content was calculated based on the sum of mannose, xylose and arabinose. To assess cellulose accessibility, staining method by DR28 was carried out as described elsewhere [ 60 ]. All the measurements were performed in duplicate.…”

Section: Methodsmentioning

confidence: 99%

Organosolv pretreatment assisted by carbocation scavenger to mitigate surface barrier effect of lignin for improving biomass saccharification and utilization

Chu

Tong

Chen

et al. 2021

Biotechnol Biofuels

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Background Ethanol organosolv (EOS) pretreatment is one of the most efficient methods for boosting biomass saccharification as it can achieve an efficient fractionation of three major constituents in lignocellulose. However, lignin repolymerization often occurs in acid EOS pretreatment, which impairs subsequent enzymatic hydrolysis. This study investigated acid EOS pretreatment assisted by carbocation scavenger (2-naphthol, 2-naphthol-7-sulfonate, mannitol and syringic acid) to improve biomass fractionation, coproduction of fermentable sugars and lignin adsorbents. In addition, surface barrier effect of lignin on cellulose hydrolysis was isolated from unproductive binding effect of lignin, and the analyses of surface chemistry, surface morphology and surface area were carried out to reveal the lignin inhibition mitigating effect of various additives. Results Four different additives all helped mitigate lignin inhibition on cellulose hydrolysis in particular diminishing surface barrier effect, among which 2-naphthol-7-sulfonate showed the best performance in improving pretreatment efficacy, while mannitol and syringic acid could serve as novel green additives. Through the addition of 2-naphthol-7-sulfonate, selective lignin removal was increased up to 76%, while cellulose hydrolysis yield was improved by 85%. As a result, 35.78 kg cellulose and 16.63 kg hemicellulose from 100 kg poplar could be released and recovered as fermentable sugars, corresponding to a sugar yield of 78%. Moreover, 22.56 kg ethanol organosolv lignin and 17.53 kg enzymatic hydrolysis residue could be recovered as lignin adsorbents for textile dye removal, with the adsorption capacities of 45.87 and 103.09 mg g−1, respectively. Conclusions Results in this work indicated proper additives could give rise to the form of less repolymerized surface lignin, which would decrease the unproductive binding of cellulase enzymes to surface lignin. Besides, the supplementation of additives (NS, MT and SA) resulted in a simultaneously increased surface area and decreased lignin coverage. All these factors contributed to the diminished surface barrier effect of lignin, thereby improving the ease of enzymatic hydrolysis of cellulose. The biorefinery process based on acidic EOS pretreatment assisted by carbocation scavenger was proved to enable the coproduction of fermentable sugars and lignin adsorbents, allowing the holistic utilization of lignocellulosic biomass for a sustainable biorefinery. Graphic abstract

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Comparative study on enzymatic digestibility of acid-pretreated poplar and larch based on a comprehensive analysis of the lignin-derived recalcitrance

Cited by 69 publications

References 35 publications

Comparison of the Interaction Modes Between Cellulase and Bovine Serum Albumin /Lignosulfonate /Polyethylene Glycol in Promoting Lignocellulose Saccharification

Comparison of the Interaction Modes Between Cellulase and Bovine Serum Albumin /Lignosulfonate /Polyethylene Glycol in Promoting Lignocellulose Saccharification

Understanding the effects of different residual lignin fractions in acid-pretreated bamboo residues on its enzymatic digestibility

Organosolv pretreatment assisted by carbocation scavenger to mitigate surface barrier effect of lignin for improving biomass saccharification and utilization

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