Pseudo-Lignin Content Decreased with Hemicellulose and Lignin Removal, Improving Cellulose Accessibility, and Enzymatic Digestibility

Schmatz, Alison Andrei; Salazar-Bryam, Ana María; Contiero, Jonas; Sant’Anna, Celso; Brienzo, Michel

doi:10.1007/s12155-020-10187-8

Cited by 35 publications

(6 citation statements)

References 30 publications

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“…[ 11 ] Various explanations for the low enzymatic digestibility efficiency have been proposed: (1) Dilute acid-pretreated bamboo residues still have inherently complex and dense structures in natural cell walls that show recalcitrance toward enzymatic hydrolysis [ 7 ]. (2) Lignin-like compounds (pseudo lignins) are formed and problematically deposited on the surfaces of fibers to adsorb enzymes unproductively [ 12 , 13 ]. (3) Lignin undergoes repolymerization reactions, which also block available surface area [ 14 ].…”

Section: Introductionmentioning

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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Section: Introductionmentioning

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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“…It was studied that different functional groups like carbonyl, carboxylic, aromatic, and aliphatic structures were present in the pseudo-lignin obtained from pretreated cellulose and holocellulose. Schmatz et al [24] applied different combinations of pretreatment techniques prior to acid hydrolysis of sugarcane bagasse at 121 °C for 30 min. It was observed that extractive free biomass leads to reduce the formation of pseudo-lignin content during acid hydrolysis process.…”

Section: Ultrastructural Morphology Of Lignin Droplets On Biomassmentioning

confidence: 99%

“…However, it was observed that lignin is condensed and redeposited on the biomass surface as a result of acid pretreatment, thereby acting as an obstacle towards enzymatic access of cellulose. Schmatz et al [24] conducted a detail study on the formation of pseudo-lignin using different structural parts of sugarcane bagasse under several process conditions, and it was observed that the extractivefree biomass leads to produce less amount of pseudo-lignin prior to the acid pretreatment compared to that of the raw biomass. In addition, co-solvent-enhanced lignocellulosic fractionation process was recently employed as an emerging pretreatment process for the removal of significant fraction of biomass lignin.…”

Section: Advancement In the Processes To Overcome The Interference Ef...mentioning

confidence: 99%

A Critical Review on the Effect of Lignin Redeposition on Biomass in Controlling the Process of Enzymatic Hydrolysis

et al. 2022

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The key factor in lignocellulosic biorefinery is to extract maximum sugars from biomass as feedstock for the process of fermentation. The major barrier in extracting the sugars is the presence of lignin of biomass that primarily restricts the accessibility of cellulose to enzymes. Therefore, it is important to locate the presence and morphology of lignin to assess the reaction severity. In most of the severe pretreatment conditions, lignin is observed to condense and form spherical droplets on the surface of treated biomass. Such formation of pseudo-lignin differs in the action of cellulose hydrolysis from that of the initial or residual lignin content of biomass. In view of that, the present review is focused on the impact of various pretreatment techniques on the morphological changes in lignin and its subsequent redeposition or redistribution effect towards enzymatic hydrolysis process. Initially, the effect of different pretreatment methods is assessed which primarily resulted into the occurrence of lignin redeposition on the surface and interior of biomass. Thereafter, an in-depth insight is provided to understand the underlying mechanism of such formations of pseudo-lignin under severe reaction conditions. Finally, the study is concluded discussing the future recommendation to circumvent the interference of pseudo-lignin on enzymatic reactions. Hence, the present review article will not only help the readers to gain the knowledge on the formations and problems of pseudo-lignin obtained from biomass but also details the latest advancements that are involved to overcome the inhibitory effect of pseudo-lignin during the enzymatic hydrolysis of biomass. Highlights• The ultrastructural morphology of pseudo-lignin in the form of droplets are discussed.• The various pretreatment processes that are responsible for the formation of pseudo-lignin are described.• An insight on the reaction mechanisms is provided for the impact of pseudo-lignin towards enzymatic hydrolysis.• Advances processes to overcome the inhibitory effect are comprehensively summarized.• Associated challenges and future recommendations are demonstrated.

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“…Degradation products of pentoses (furfural) and hexoses (5-hydroxymethylfurfural) have little effect on the inhibition of cellulase enzymes but are toxic in the fermentation process [15]. However, furfural and 5-hydroxymethyl furfural are key compounds in the formation of pseudo-lignin.…”

Section: Introductionmentioning

confidence: 99%

Lignin Removal and Cellulose Digestibility Improved by Adding Antioxidants and Surfactants to Organosolv Pretreatment of Sugarcane Bagasse

2021

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Annually, tons of sugarcane bagasse are generated in the sugar and alcohol industries. This biomass has great potential in the use of converting cellulose into glucose, an energy currency for various biotechnological processes. However, lignin content is a limiting factor in cellulose accessibility. This study aimed to improve lignin removal by evaluating the additive's effect on biomass pretreatment. The additives were tert-butylhydroquinone, 3-tert-butyl-4-hydroxyanisole, methyl 3,4,5-trihydroxybenzoate; surfactants Tween 20, Tween 80, and dimethyl sulfoxide (DMSO). The antioxidants collaborated with lignin removal; the 3-tert-butyl-4-hydroxyanisole reached 71% of lignin removal. Inherent to the pretreatment, tert-butylhydroquinone showed 23.53% and 89.54% of cellulose and hemicellulose removal, respectively. Dioxane extraction compounds from the pretreated biomass showed an increased amount using additives, suggesting more compounds adsorbed on the material surface. All the antioxidants/surfactants applied to the organosolv pretreatment improved enzymatic hydrolysis, reaching 98.9% cellulose into glucose conversion (Tween 80). The use of chemical compounds during pretreatment beneficed the removal of lignin from biomass and consequently the cellulose hydrolysis.

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Pseudo-Lignin Content Decreased with Hemicellulose and Lignin Removal, Improving Cellulose Accessibility, and Enzymatic Digestibility

Cited by 35 publications

References 30 publications

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

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

A Critical Review on the Effect of Lignin Redeposition on Biomass in Controlling the Process of Enzymatic Hydrolysis

Lignin Removal and Cellulose Digestibility Improved by Adding Antioxidants and Surfactants to Organosolv Pretreatment of Sugarcane Bagasse

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