Insight into the structure-function relationships of deep eutectic solvents during rice straw pretreatment

Hou, Xue-Dan; Li, Aolin; Lin, Kai-Peng; Wang, Yuan‐Yuan; Kuang, Zhi-Yin; Cao, Shi‐Lin

doi:10.1016/j.biortech.2017.10.019

Cited by 174 publications

(48 citation statements)

References 39 publications

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“…The results show that a higher lignin yield was achieved for monocarboxylic-based DESs, than for the corresponding di- or tricarboxylic acids. The same relationship was also found by Hou et al [175] for DES extraction of rice straw. Tan et al suggests that the increase of possible hydrogen-bonding sites in di- or tri-carboxylic acids may restrict the mobility of solvent molecules, which weakens the solvent–lignin interaction thus decreasing the lignin-extraction efficacy.…”

Section: Pretreatment Methodssupporting

confidence: 87%

Pretreatment for biorefineries: a review of common methods for efficient utilisation of lignocellulosic materials

Galbe

Wallberg

2019

Biotechnol Biofuels

310

167

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The implementation of biorefineries based on lignocellulosic materials as an alternative to fossil-based refineries calls for efficient methods for fractionation and recovery of the products. The focus for the biorefinery concept for utilisation of biomass has shifted, from design of more or less energy-driven biorefineries, to much more versatile facilities where chemicals and energy carriers can be produced. The sugar-based biorefinery platform requires pretreatment of lignocellulosic materials, which can be very recalcitrant, to improve further processing through enzymatic hydrolysis, and for other downstream unit operations. This review summarises the development in the field of pretreatment (and to some extent, of fractionation) of various lignocellulosic materials. The number of publications indicates that biomass pretreatment plays a very important role for the biorefinery concept to be realised in full scale. The traditional pretreatment methods, for example, steam pretreatment (explosion), organosolv and hydrothermal treatment are covered in the review. In addition, the rapidly increasing interest for chemical treatment employing ionic liquids and deep-eutectic solvents are discussed and reviewed. It can be concluded that the huge variation of lignocellulosic materials makes it difficult to find a general process design for a biorefinery. Therefore, it is difficult to define "the best pretreatment" method. In the end, this depends on the proposed application, and any recommendation of a suitable pretreatment method must be based on a thorough techno-economic evaluation.

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Section: Pretreatment Methodssupporting

confidence: 87%

Pretreatment for biorefineries: a review of common methods for efficient utilisation of lignocellulosic materials

Galbe

Wallberg

2019

Biotechnol Biofuels

310

167

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“…Both molecules have been used in the literature as HBD constituents of DESs formed by mixing with choline chloride, 47 and their mixtures have been applied for the treatment of biomass. 48 In the present work, we have studied lactic acid:glycerol mixtures by comparison to ethaline DESs in order to determine the impact of switching-off the electrostatic interactions. Indeed, apart from a small difference concerning the HBD (glycerol instead of ethylene glycol), the main difference between these two systems is the substitution of the HBA ionic choline chloride by the non-ionic (or partially ionic) H-bonded carboxylic acid.…”

Section: Introductionmentioning

confidence: 99%

Do Deep Eutectic Solvents Form Uniform Mixtures Beyond Molecular Microheterogeneities?

et al. 2020

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We have performed small angle neutron scattering (SANS) in a momentum transfer range (0.05 < Q < 0.5 Å -1 ) to study long range order and concentration fluctuations in deep eutectic solvents (DESs) and their aqueous solutions. Ethaline (choline chloride:ethylene glycol), glycerol:lactic acid, and menthol:decanoic acid mixtures were selected to illustrate respectively the case of ionic, nonionic and hydrophobic mixtures. Different carefully designed isotopic labelling was used to emphasize selectively the spatial correlations between the different solvent components. For ethaline DESs and their aqueous solutions, a weak low-Q peak observed only for certain compositions and some partial structure factors revealed the mesoscopic segregation of ethylene glycol molecules that do not participate to the solvation of ionic units, either because they are in excess with respect the eutectic stoichiometry (1:4 neat ethaline) or substituted by water 2 (4w-ethaline and higher aqueous dilutions). For the nonionic hydrophilic solutions, such a mesoscopic segregation was not observed. This indicates that the better balanced interactions between the three nonionic H-bonded components (water, lactic acid, and glycerol) favor homogeneous mixing. For the hydrophobic DESs, we observed an excess of coherent scattering intensity centered at Q = 0, which could be reproduced by a model of non-interacting spherical domains. Local concentration fluctuations are not excluded either. However, unlike liquid mixtures with a tendency to demix, we have found no evidence of expansion of domains with different compositions to a large scale.

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“…The DES, choline chloride- lactic acid (ChCl-Lac), used in this study was prepared as reported previously ( Hou et al, 2017b ). Briefly, choline chloride and lactic acid were mixed in a glass vial in molar ratio 1:2 and heated up to 90°C for 0.5 h with stirring until a clear liquid was obtained.…”

Section: Methodsmentioning

confidence: 99%

Enhancing the Thermostability of Papain by Immobilizing on Deep Eutectic Solvents-Treated Chitosan With Optimal Microporous Structure and Catalytic Microenvironment

Lin

Feng

et al. 2020

Front. Bioeng. Biotechnol.

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Deep eutectic solvents (DESs) have attracted an increasing attention in the fields of biocatalysis and biopolymer processing. In this study, papain immobilized on choline chloride- lactic acid (ChCl-Lac) DES-treated chitosan exhibited excellent thermostability as compared to the free enzyme. The properties of native or DES-treated chitosan and immobilized enzyme were characterized by FT-IR, SEM, surface area and pore property analysis. Like the common enzyme immobilization, papain immobilized on DES-treated chitosan resulted in a lower catalytic efficiency and a higher thermostability than the free enzyme due to the restricted diffusion. The results also revealed that DES could control the active group content, thus achieving the appropriate microporous structure of immobilized enzyme. Meanwhile, it could also help to construct the optimal microenvironment by hydrogen-bonding interaction between enzyme, chitosan, and residual DES, which are benefit for maintaining an active conformation and subsequently a high thermostability of papain. Moreover, it was found that trace DES (10 mM) significantly promoted the activity of free papain (145%). Deactivation thermodynamics study showed that the DES could enhance the thermostability of papain especially at high temperature (half-life of 7.4 vs. 3.5 h) because of the increased Gibbs free energy of denaturation. Secondary structure analysis by circular dichroism spectroscopy (CD) agreed well with the activity and thermostability data, further confirming the formation of rigid conformation induced by a specific amount of DES. This work provides a new way of enzyme immobilization synergistically intensified by solvents and supporting materials to achieve better microporous structure and catalytic microenvironment.

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Insight into the structure-function relationships of deep eutectic solvents during rice straw pretreatment

Cited by 174 publications

References 39 publications

Pretreatment for biorefineries: a review of common methods for efficient utilisation of lignocellulosic materials

Pretreatment for biorefineries: a review of common methods for efficient utilisation of lignocellulosic materials

Do Deep Eutectic Solvents Form Uniform Mixtures Beyond Molecular Microheterogeneities?

Enhancing the Thermostability of Papain by Immobilizing on Deep Eutectic Solvents-Treated Chitosan With Optimal Microporous Structure and Catalytic Microenvironment

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