Effect of crystallinity on pretreatment and enzymatic hydrolysis of lignocellulosic biomass based on multivariate analysis

Xu, Huanfei; Che, Xinpeng; Ding, Yu; Kong, Yi; Li, Bin; Tian, Wende

doi:10.1016/j.biortech.2018.12.096

Cited by 77 publications

(23 citation statements)

References 41 publications

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“…HWP also had an impact on the ultrastructure of the cellulose by increasing its crystallinity and LFD. Crystallinity is often described as a limiting factor in enzymatic hydrolysis [ 7 , 104 , 105 ]. In the present study, the increase in the crystallinity of the cellulose resulting from the loss of more hydrolysable amorphous cellulose during HWP, had no negative impact on the saccharification capacity of the CWR ( R 2 = 0.91).…”

Section: Resultsmentioning

confidence: 99%

Evaluating polymer interplay after hot water pretreatment to investigate maize stem internode recalcitrance

Leroy

Falourd

Foucat

et al. 2021

Biotechnol Biofuels

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Background Biomass recalcitrance is governed by various molecular and structural factors but the interplay between these multiscale factors remains unclear. In this study, hot water pretreatment (HWP) was applied to maize stem internodes to highlight the impact of the ultrastructure of the polymers and their interactions on the accessibility and recalcitrance of the lignocellulosic biomass. The impact of HWP was analysed at different scales, from the polymer ultrastructure or water mobility to the cell wall organisation by combining complementary compositional, spectral and NMR analyses. Results HWP increased the kinetics and yield of saccharification. Chemical characterisation showed that HWP altered cell wall composition with a loss of hemicelluloses (up to 45% in the 40-min HWP) and of ferulic acid cross-linking associated with lignin enrichment. The lignin structure was also altered (up to 35% reduction in β–O–4 bonds), associated with slight depolymerisation/repolymerisation depending on the length of treatment. The increase in $${T}_{1\rho }^{H}$$ T 1 ρ H , $${T}_{HH}$$ T HH and specific surface area (SSA) showed that the cellulose environment was looser after pretreatment. These changes were linked to the increased accessibility of more constrained water to the cellulose in the 5–15 nm pore size range. Conclusion The loss of hemicelluloses and changes in polymer structural features caused by HWP led to reorganisation of the lignocellulose matrix. These modifications increased the SSA and redistributed the water thereby increasing the accessibility of cellulases and enhancing hydrolysis. Interestingly, lignin content did not have a negative impact on enzymatic hydrolysis but a higher lignin condensed state appeared to promote saccharification. The environment and organisation of lignin is thus more important than its concentration in explaining cellulose accessibility. Elucidating the interactions between polymers is the key to understanding LB recalcitrance and to identifying the best severity conditions to optimise HWP in sustainable biorefineries.

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Section: Resultsmentioning

confidence: 99%

Evaluating polymer interplay after hot water pretreatment to investigate maize stem internode recalcitrance

Leroy

Falourd

Foucat

et al. 2021

Biotechnol Biofuels

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“…But the impact of crystallinity on hydrolysis differs. Some studies reported that crystallinity correlated negatively with enzymatic hydrolysis especially at the initial hydrolysis rate on pre-treated wheat straw (Pihlajaniemi et al, 2016), on pre-treated corn stover (Liu et al, 2014;Xu et al, 2019) and on hybrid polar, switchgrass, and bagasse (Chang and Holtzapple, 2000). Others showed that crystallinity was less critical in limiting hydrolysis than other physical features such as DP, pore volume, accessible surface area, and particle size (Mansfield et al, 1999;Ioelovich and Morag, 2011;Aldaeus et al, 2015;Auxenfans et al, 2017a;Meng et al, 2017;Zhang et al, 2018).…”

Section: Physical Factors Impacting Enzymatic Hydrolysismentioning

confidence: 99%

Lignocellulosic Biomass: Understanding Recalcitrance and Predicting Hydrolysis

2019

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Lignocellulosic biomass (LB) is an abundant and renewable resource from plants mainly composed of polysaccharides (cellulose and hemicelluloses) and an aromatic polymer (lignin). LB has a high potential as an alternative to fossil resources to produce second-generation biofuels and biosourced chemicals and materials without compromising global food security. One of the major limitations to LB valorisation is its recalcitrance to enzymatic hydrolysis caused by the heterogeneous multi-scale structure of plant cell walls. Factors affecting LB recalcitrance are strongly interconnected and difficult to dissociate. They can be divided into structural factors (cellulose specific surface area, cellulose crystallinity, degree of polymerization, pore size and volume) and chemical factors (composition and content in lignin, hemicelluloses, acetyl groups). Goal of this review is to propose an up-to-date survey of the relative impact of chemical and structural factors on biomass recalcitrance and of the most advanced techniques to evaluate these factors. Also, recent spectral and water-related measurements accurately predicting hydrolysis are presented. Overall, combination of relevant factors and specific measurements gathering simultaneously structural and chemical information should help to develop robust and efficient LB conversion processes into bioproducts.

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“…However, the valorization of LB remains a challenge because of its complex structure and chemical composition, which makes it naturally recalcitrant to enzymatic degradation [4]. Despite extensive research on identifying the chemical and structural parameters underlying LB recalcitrance, such as lignin content [5], cellulose crystallinity [6], degree of polymerization [7] and porosity [8], the identified parameters are not universal, but rather, specific to the biomass species and pretreatment type. Moreover, structural parameters at cellular and tissular scale have not been investigated.…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Imaging of Plant Cell Wall Deconstruction Using Fluorescence Confocal Microscopy

Zoghlami

Refahi

Terryn

et al. 2020

Sustainable Chemistry

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Lignocellulosic biomass (LB) is recalcitrant to enzymatic hydrolysis due to its compact and complex cell wall structure. To identify the parameters behind LB recalcitrance, experimental data over hydrolysis time must be collected. Here, we describe a novel method to collect time-lapse images during cell wall deconstruction by enzymatic hydrolysis. The protocol includes instructions for sample preparation, layout of a custom designed incubation chamber and instructions for confocal time lapse acquisition. The protocol sets out a detailed plan where cross-sections of untreated and pretreated poplar samples are mounted in a sealed frame containing a buffer and an enzymatic cocktail. The sealed frame is then placed into an incubator to maintain the sample at a constant temperature of 50 °C, which is optimal for enzymatic reaction while avoiding enzymatic cocktail evaporation. Using lignin natural autofluorescence, confocal z-stacks of untreated and pretreated samples were acquired at regular time intervals during enzymatic hydrolysis for 24 h. Acquisition parameters were optimized to compromise between image resolution and reduced photo-bleaching. The acquired image might then be processed by further development of algorithms to extract precise quantitative information on cell wall deconstruction. This protocol is an important first step towards elucidating the underlying parameters of LB recalcitrance by allowing the acquisition of high-quality images of LB hydrolysis for extracting quantitative data on LB deconstruction.

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Effect of crystallinity on pretreatment and enzymatic hydrolysis of lignocellulosic biomass based on multivariate analysis

Cited by 77 publications

References 41 publications

Evaluating polymer interplay after hot water pretreatment to investigate maize stem internode recalcitrance

Evaluating polymer interplay after hot water pretreatment to investigate maize stem internode recalcitrance

Lignocellulosic Biomass: Understanding Recalcitrance and Predicting Hydrolysis

Three-Dimensional Imaging of Plant Cell Wall Deconstruction Using Fluorescence Confocal Microscopy

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