Bacteria-enhanced dilute acid pretreatment of lignocellulosic biomass

Xu, Yan; Wang, Zhongren; Zhang, Kejing; Si, Mengying; Liu, Mingren; Chai, Liyuan; Liu, Xueduan; Shi, Yan

doi:10.1016/j.biortech.2017.08.037

Cited by 94 publications

(42 citation statements)

References 48 publications

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“…In contrast, the surface of CS pretreated under TH21 was changed ( Figure 2b). Some lignin droplets were deposited on the surface of the pretreated residues which was similar to the phenomenon that was found in our previous work [9]. The formation of lignin droplets was caused by the acidic environment created by adding sulfuric acid as a catalyst in THF-H 2 O reaction system.…”

Section: Morphology Change Of Cssupporting

confidence: 83%

“…Therefore, the removal of the outer lignin in lignocellulosic biomass has become the primary mission via pretreatment methods. Currently, a great many pretreatment strategies based on acid, alkali and organic solvent et al were employed to efficiently remove or solve lignin from lignocellulose, which improve the glucose releasing [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

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Utilization of all components in biomass through high reducing sugar production and lignin nanoparticles preparation

Liu¹,

Zhuo²,

Su³

et al. 2019

Preprint

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BackgroundLignocellulosic biomass for biofuel production was considered as an effective way to develop new energy. However, the efficient sugar conversion of cellulose and practical utilization of lignin are great challenges for sustainable biorefinery. In addition, sugar conversion and lignin utilization are generally performed separately. In this study, high reducing sugar production and multiple lignin nanoparticles preparation were realized in a pattern based on tetrahydrofuran-water (THF-H2O) pretreatment of corn straw (CS). ResultsThe maximum production of the reducing sugar was 26.79 g/l, which was significantly higher than the theoretical yield of 20.65 g/l. Lignin nanoparticles with different sizes ranged from 239 to 798 nm were prepared using dissolved lignin in the supernatant fluid from different THF-H2O pretreatment conditions through self-assembly with introducing water. The formation of lignin particles with different sizes were influenced by soluble lignin characteristics in the pretreatment liquid. The lignin molecular, functional groups, and structure were explored to elucidate the effects on the variation of lignin particles sizes by GPC, FTIR, and 2D-HSQC-NMR. The guaiacyl (G)-type lignin was easier to be dissolved in the mild pretreatment liquid, contributing to form smaller lignin nanoparticles with a good dispersibility. Comparatively, a small content of syringyl- and G-type lignin which caused by the lignin depolymerization retained in the severe pretreatment liquid to form the larger sphere particles. ConclusionsThe optimal pretreatment under TH22 (THF-H2O pretreatment at 120 °C for 2 h) simultaneously realized the utilization of all components in biomass through high reducing sugar production and the smaller lignin particles preparation. This new pattern of CS pretreatment plays a novel perspective for the technical design of lignocellulosic biomass conversion.

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Section: Morphology Change Of Cssupporting

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Utilization of all components in biomass through high reducing sugar production and lignin nanoparticles preparation

Liu¹,

Zhuo²,

Su³

et al. 2019

Preprint

Self Cite

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“…In our previous work, Cupriavidus basilensis B-8 (here after B-8), isolated from the steeping fluid of eroding bamboo slips, was identified as a potential bacterium for lignin degradation [ 22 ]. Here, inspired by natural lignocellulose degradation systems, we hope to combine mild chemical pretreatment with B-8 to rapidly simulate fungal invasion of plant tissue.…”

Section: Introductionmentioning

confidence: 99%

A bionic system with Fenton reaction and bacteria as a model for bioprocessing lignocellulosic biomass

Zhang

Liú

et al. 2018

Biotechnol Biofuels

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BackgroundThe recalcitrance of lignocellulosic biomass offers a series of challenges for biochemical processing into biofuels and bio-products. For the first time, we address these challenges with a biomimetic system via a mild yet rapid Fenton reaction and lignocellulose-degrading bacterial strain Cupriavidus basilensis B-8 (here after B-8) to pretreat the rice straw (RS) by mimicking the natural fungal invasion process. Here, we also elaborated the mechanism through conducting a systematic study of physicochemical changes before and after pretreatment.ResultsAfter synergistic Fenton and B-8 pretreatment, the reducing sugar yield was increased by 15.6–56.6% over Fenton pretreatment alone and 2.7–5.2 times over untreated RS (98 mg g−1). Morphological analysis revealed that pretreatment changed the surface morphology of the RS, and the increase in roughness and hydrophilic sites enhanced lignocellulose bioavailability. Chemical components analyses showed that B-8 removed part of the lignin and hemicellulose which caused the cellulose content to increase. In addition, the important chemical modifications also occurred in lignin, 2D NMR analysis of the lignin in residues indicated that the Fenton pretreatment caused partial depolymerization of lignin mainly by cleaving the β-O-4 linkages and by demethoxylation to remove the syringyl (S) and guaiacyl (G) units. B-8 could depolymerize amount of the G units by cleaving the β-5 linkages that interconnect the lignin subunits.ConclusionsA biomimetic system with a biochemical Fenton reaction and lignocellulose-degrading bacteria was confirmed to be able for the pretreatment of RS to enhance enzymatic hydrolysis under mild conditions. The high digestibility was attributed to the destruction of the lignin structure, partial hydrolysis of the hemicellulose and partial surface oxidation of the cellulose. The mechanism of synergistic Fenton and B-8 pretreatment was also explored to understand the change in the RS and the bacterial effects on enzymatic hydrolysis. Furthermore, this biomimetic system offers new insights into the pretreatment of lignocellulosic biomass.Electronic supplementary materialThe online version of this article (10.1186/s13068-018-1035-x) contains supplementary material, which is available to authorized users.

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“…Pretreatment of lignocellulosic biomass with dilute mineral acids under mild conditions has been found to effectively separate and break down hemicellulose, modify the lignin network and increase cellulose accessibility [8,9]. Overall, the technology of dilute-acid pretreatment is being actively studied and applied; in 2017 alone, a number of papers have been published in the field of dilute-acid pretreatment of biomass [10][11][12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Kinetic Modelling and Experimental Studies for the Effects of Fe2+ Ions on Xylan Hydrolysis with Dilute-Acid Pretreatment and Subsequent Enzymatic Hydrolysis

et al. 2018

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High-temperature (150-170 • C) pretreatment of lignocellulosic biomass with mineral acids is well established for xylan breakdown. Fe 2+ is known to be a cocatalyst of this process although kinetics of its action remains unknown. The present work addresses the effect of ferrous ion concentration on sugar yield and degradation product formation from corn stover for the entire two-step treatment, including the subsequent enzymatic cellulose hydrolysis. The feedstock was impregnated with 0.5% acid and 0.75 mM iron cocatalyst, which was found to be optimal in preliminary experiments. The detailed kinetic data of acid pretreatment, with and without iron, was satisfactorily modelled with a four-step linear sequence of first-order irreversible reactions accounting for the formation of xylooligomers, xylose and furfural as intermediates to provide the values of Arrhenius activation energy. Based on this kinetic modelling, Fe 2+ turned out to accelerate all four reactions, with a significant alteration of the last two steps, that is, xylose degradation. Consistent with this model, the greatest xylan conversion occurred at the highest severity tested under 170 • C/30 min with 0.75 mM Fe 2+ , with a total of 8% xylan remaining in the pretreated solids, whereas the operational conditions leading to the highest xylose monomer yield, 63%, were milder, 150 • C with 0.75 mM Fe 2+ for 20 min. Furthermore, the subsequent enzymatic hydrolysis with the prior addition of 0.75 mM of iron(II) increased the glucose production to 56.3% from 46.3% in the control (iron-free acid). The detailed analysis indicated that conducting the process at lower temperatures yet long residence times benefits the yield of sugars. The above kinetic modelling results of Fe 2+ accelerating all four reactions are in line with our previous mechanistic research showing that the pretreatment likely targets multiple chemistries in plant cell wall polymer networks, including those represented by the C-O-C and C-H bonds in cellulose, resulting in enhanced sugar solubilization and digestibility.

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Bacteria-enhanced dilute acid pretreatment of lignocellulosic biomass

Cited by 94 publications

References 48 publications

Utilization of all components in biomass through high reducing sugar production and lignin nanoparticles preparation

Utilization of all components in biomass through high reducing sugar production and lignin nanoparticles preparation

A bionic system with Fenton reaction and bacteria as a model for bioprocessing lignocellulosic biomass

Kinetic Modelling and Experimental Studies for the Effects of Fe2+ Ions on Xylan Hydrolysis with Dilute-Acid Pretreatment and Subsequent Enzymatic Hydrolysis

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