Types Of Deep Eutectic Solvents Research Articles

Responsive deep eutectic solvents: mechanisms, applications and their role in sustainable chemistry.

In an era so focused on sustainability, it is important to improve chemical processes by developing and using more environmentally friendly solvents and technologies. Deep eutectic solvents (DES) have proven to be a promising replacement for conventional solvents. In recent years, a new type of DES has emerged that responds to various stimuli. These responsive DES (RDES) may offer all the advantages of DES while allowing the recycling and reuse of solvents. As such, RDES can further contribute to a greener future. This review provides an overview of the diverse types of RDES, their switching mechanisms and their application in several fields. Lastly, it offers a critical perspective on current shortcomings and prospects.

Efficient and green preparation of baicalein from Radix scutellariae with deep eutectic solvent pretreated bioconversion of cellulose-based microreactor

To enhance the bioconversion ratio, an efficient and green bioconversion method for the preparation of baicalein with a microreactor composed of edible microorganisms (Aspergillus oryzae and Yeast) treated with deep eutectic solvent co-immobilized on magnetic cellulose was investigated. Various types of deep eutectic solvents (DES) were screened to obtain a superior biocatalytic effect. NADES (CHCL/EG) harvested the maximum catalytic effect at 1.0 wt% under optimal conditions (concentration of bacterium 1.5 × 107 (C × 107 cells/mL), wet weight of microreactor 12 g, incubation temperature 33 °C and pH 5.0, liquid-solid ratio 30:1 (mL/g), incubation time 48 h), baicalein reached 66.36 mg/g, which increased 3.46-fold to that of normal sample after optimizing. DES could increase the permeability of the cell membrane. The bioconversion rate of baicalin reached 97.2%.Moreover, IC50 values of the extracts measured by the DPPH-radical scavenging test were 0.366 mg/mL (control sample 0.674 mg/mL). The residual activity of the microreactor was 80.2 % after using it 14 times. The experimental results showed that bioconversion is an effective method for preparing baicalein from the plants.

Simultaneous enantioseparation of citrus flavonoids in chiral microemulsion electrokinetic chromatography using deep eutectic solvents

A novel, deep eutectic solvent (DES)-assisted sodium cholate (SC)-chiral microemulsion electrokinetic chromatography method is presented for separation of five flavonoid glycoside enantiomers, namely hesperidin, naringin, narirutin, eriocitrin, and neoeriocitrin. Herein, we develop a novel, green DES, whose addition considerably enhances the separation performance through multiple synergistic effects. A series of factors notably affecting chiral separation are systematically optimized: type and concentration of cyclodextrin, DES, and SC, oil phase type, and pH. The microemulsion comprises 0.5 % (v/v) n-octanol, 0.6 % (v/v) DES prepared using betaine and citric acid, 20 mM 2-HP-β-CD, 100 mM scdium cholate hydrate, and 15 mM borax buffer under the optimized conditions. Enantioseparations of the five enantiomers are achieved within 7 min, with resolutions ranging from 1.29 to 2.88. The method developed provides an innovative and effective way for chiral separation of enantiomers in complex food matrices.

Efficient ultrasonic extraction of alkaloids and glycosides from Camptotheca acuminata Decne via deep eutectic solvents: Kinetics and mechanisms

The study investigated the extraction of alkaloids and glycosides from the Camptotheca acuminata Decne using deep eutectic solvent (DES). 18 types of deep eutectic solvents (DESs) were prepared, and it was found that the extraction performance of choline chloride (ChCl)-formic acid (FA) was optimal, surpassing traditional solvents such as methanol/70 % methanol. In comparison to methanol, the extracted amount of compounds by DES was 2–3 times higher. The extraction processes involving the molar ratio of ChCl-FA, pH, DES/H2O mass ratio, solid/liquid ratio, as well as ultrasonic power were optimized. A mathematical model for solid/liquid extraction kinetics from Camptotheca acuminata Decne was developed. The extraction mechanism was investigated using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and 1H nuclear magnetic resonance(1H NMR). The results revealed that the DES caused dissociation in Camptotheca acuminata Decne and formed hydrogen bonds with Camptothecin (CPT). Meanwhile, density functional theory (DFT) calculations verified that FA-based exhibited the highest extracted amount for CPT. In addition, this study investigated the recovery rate of DES, and the results showed that after 10 cycles, the DES system remained effective for the extraction of alkaloids and glycosides.

Maximizing Degumming Efficiency for Firmiana simplex Bark Using Deep Eutectic Solvents.

Degumming is a critical process in the purification of natural fibers, essential for enhancing their quality and usability across various applications. Traditional degumming methods employed for natural fibers encounter inherent limitations, encompassing prolonged procedures, excessive energy consumption, adverse environmental impact, and subpar efficiency. To address these challenges, a groundbreaking wave of degumming technique has emerged, transcending these constraints and heralding a new era of efficiency, sustainability, and eco-friendly techniques. This study represents the Firmiana simplex bark (FSB) fiber's delignification by using deep eutectic solvents (DESs). The study explores the application of deep eutectic solvents, by synthesizing different types of DES using a hydrogen bond acceptor (HBA) and four representative hydrogen bond donors (HBDs) for FSB fiber degumming. This study investigates the morphologies, chemical compositions, crystallinities, and physical properties of Firmiana simplex bark fibers before and after the treatment. Furthermore, the effects and mechanisms of different DESs on dispersing FSB fibers were examined. The experimental results showed that choline chloride-urea (CU)-based DES initiates the degumming process by effectively disrupting the hydrogen bond interaction within FSB fibers, primarily by outcompeting chloride ions. Following this initial step, the DES acts by deprotonating phenolic hydroxyl groups and cleaving β-O-4 bonds present in diverse lignin units, thereby facilitating the efficient removal of lignin from the fibers. This innovative approach resulted in significantly higher degumming efficiency and ecofriendly as compared to traditional methods. Additionally, the results revealed that CU-based DES exhibits the utmost effectiveness in degumming FSB fibers. The optimal degumming conditions involve a precise processing temperature of 160 °C and a carefully controlled reaction time of 2 h yielding the most favorable outcomes. The present study presents a novel straightforward and environmentally friendly degumming method for Firmiana simplex bark, offering a substantial potential for enhancing the overall quality and usability of the resulting fibers. Our findings open new pathways for sustainable fiber-processing technologies.

Influence of Different Deep Eutectic Solvents and Plant Extracts on Antioxidant, Mechanical, and Color Properties of Alginate Film.

Eco-friendly functional alginate films with plant extracts (chokeberry pomace (ChP) or lemon balm (LB) herb) were obtained. Moreover, deep eutectic solvents (DESs) based on choline chloride, glucose, and betaine were used to acquire the active substances from plant materials. The films were tested regarding the antioxidant, mechanical, and color properties. The results revealed that the films' antioxidant capacities (AC) depended on the extract type and DES used, namely AC values for alginate films with LB were higher than those with ChP. Moreover, the results of the films' mechanical properties depended only on the DES, which acted as a plasticizer in most cases. Furthermore, the color analysis of the studied films showed a dependence on the type of extract and DES. The lightness (L*) was influenced only by the DES type, while the solvent and extract type affected the a* and b* values. Our results show that the films can be applied as active packaging for food products.

Comprehensive evaluation of physical properties and carbon dioxide capacities of new 2-(butylamino)ethanol-based deep eutectic solvents

Abstract The aim of this research was to assess the impact of the components of alkanolamine deep eutectic solvents (DESs) on the physical properties of those DESs and their carbon dioxide capacity. To achieve this goal, novel deep eutectic solvents were synthesized by using 2-(butylamino)ethanol (BAE) as the hydrogen bond donor (HBD), along with tetrabutylammonium bromide TBAB), tetrabutylammonium chloride (TBAC), or tetraethylammonium chloride (TEAC) as the hydrogen bond acceptors (HBA) at various molar ratios (1:6, 1:8, and 1:10). To confirm the presence of hydrogen bond interactions between the components Fourier Transform Infrared Spectroscopy measurements were conducted. Furthermore, thermal properties, including melting points and thermal stability, of these deep eutectic solvents as well as key physical properties, such as density, viscosity, refractive index, and sound velocity, within the temperature range of 293.15–333.15 K and at a pressure of 0.1 MPa were examined. The effect of the molar ratio of HBA to HBD, the type of anion, and the length of the alkyl chain were studied and analysed in regard to physicochemical properties. In this work, the solubility of carbon dioxide in DESs derived from 2-(butylamino)ethanol, 3-aminopropan-1-ol (AP), and 2-(methylamino)ethanol (MAE) was measured. The highest CO2 capacity was found for TEAC:MAE 1:10 DES characterized by the shortest alkyl chain length in both HBA and HBD molecules, the highest amine content, and the lowest viscosity. Additionally, the effect of water addition on carbon dioxide solubility was explored. The results showed that the influence of water on CO2 solubility varies with the type of DES. In general, this work highlighted that DESs can serve as effective media for carbon dioxide capture, and their performance can be tailored by changing the type of hydrogen bond acceptor or donor, their molar ratio and by the addition of water.

Ab initio molecular dynamics study of hydroxyl positioning in butanediol and its impact on deep eutectic solvent structure

Electrolytes play a crucial role in enhancing the performance of energy storage devices, including batteries and supercapacitors. However, traditional electrolytes, such as aqueous solutions, organic solvents, and ionic liquids, exhibit inherent limitations and challenges. Deep eutectic solvents have recently emerged as promising alternatives due to their environmentally friendly nature and favorable properties. Despite their widespread applications in various domains, their potential as electrolytes remains relatively underexplored. This study investigates three distinct types of deep eutectic solvents derived from different isomers of butanediols combined with choline chloride. Ab initio molecular dynamics simulations are employed to analyze the microstructure of these deep eutectic solvents, focusing on non-covalent electrostatic interactions, hydrogen bonding patterns, and vibrational spectra. The results reveal significant differences in the structural configuration of hydrogen bond acceptors and hydrogen bond donors and their interactions within the deep eutectic solvents. Specifically, the positioning of functional groups in hydrogen bond donors significantly impacts the hydrogen bonding network and the interaction with monoatomic ions. Moreover, the vibrational spectra analysis highlights the existence of hydrogen bonds involving stretching modes of the OH group, as evidenced by redshift deviations. Overall, this study provides valuable insights into the unique features of deep eutectic solvents as potential electrolytes for energy storage applications. The comprehensive analysis of their microstructure and vibrational properties enhances our understanding of deep eutectic solvent utilization and opens avenues for further research in sustainable energy storage.

Transparent, thermal stable, water resistant and high gas barrier films from cellulose nanocrystals prepared by reactive deep eutectic solvents

Nanocellulose-based film, as a novel new type of film mainly made of nanosized cellulose, has demonstrated an ideal combination of renewability and enhanced or novel properties. Considerable efforts have been made to enhance its intrinsic properties or create new functions to expand its applications, such as in food packaging, water treatment or flexible electronics. In this paper, two different types of deep eutectic solvents (guanidine sulfamate-glycerol and guanidine sulfamate-choline chloride) were formulated and applied to prepare cellulose nanocrystals with dialdehyde cellulose (DAC). The effects of reaction conditions including time, temperature and cellulose-DES ratio on the grafting degree and yield were studied. After ultrasonication, two types of CNCs, with an average diameter of 3–5 nm and an average length of 140.7–204.2 nm, were obtained. The synthesized CNCs displayed an enhanced thermal stability compared to pristine cellulose. Moreover, highly transparent (light transmittance higher than 90 %) and water stable nanocellulose based films (a wet tensile strength of higher than 30 MPa after immersing in water for 24 h) were fabricated. Besides, the obtained films exhibited low oxygen transmission rate, showing a good potential application in food packaging.

Polyamide and deep eutectic solvent assisted matrix solid-phase dispersion microextraction for strong hydrophobic compounds

This paper proposes a simple, efficient, and green matrix solid-phase dispersion microextraction (MSPDM) method that uses polyamide as a dispersant and deep eutectic solvent (DES) as an eluant to extract terpenoids and alkaloid compounds from linderae radix. The main extraction parameters, including the amount of dispersant, grinding time, molar ratio of the DES components, type of dispersant, and type of DES, were optimized using single-factor experiments. The response surface methodology and the Box–Behnken design were used for further optimization. Satisfactory linearity (R2 > 0.999), precision (0.018%–2.215%), and accuracy (recovery >80%) were acquired for all target analytes. The results indicate that the developed method is promising and sustainable for extracting active ingredients from natural products.

Green and efficient extraction of polyphenols from the leaves of Quercus dentata Thunb and in vitro antioxidant activities of polyphenol extract

The ultrasonic-coupled deep eutectic solvents method was firstly applied to extract phenolic compounds efficiently from the leaves of Quercus dentata Thunb. Five factors including type of deep eutectic solvent, water content, solid-liquid ratio, extraction time and extraction temperature were investigated based on total polyphenol content. The optimal extraction parameters were obtained through response surface methodology, that is, the deep eutectic solvent was composed of choline chloride and 1, 4-butanediol (molar ratio 1:2) with water content of 38%, the solid-liquid ratio was 1:30 g/mL, the extraction time was 31 min, the extraction temperature was 55 °C. At this condition, total polyphenol content reached the highest value of 78.56 ± 2.44 mg gallic acid/g. In addition, eleven phenolic compounds were identified by high performance liquid chromatography quadrupole/time-of flight mass spectrometry as flavonol glycosides. And then, the extraction showed good antioxidant activities in reducing transition metals (Fe3+, Cu2+, Mo6+) and scavenging free radicals (DPPH·, ABTS+·, O2−· and ·OH). Among them, the IC50 values of scavenging DPPH·, ABTS+·, O2−· and ·OH free radicals were 10.87 ± 0.25 μg mL−1, 8.04 ± 0.24 μg/mL, 149.47 ± 5.27 μg/mL and 131.73 ± 5.31 μg/mL, respectively. On the other hand, the extraction at the cellular level exerted its protective effect on PC12 cells by increasing the cell survival rate of H2O2-induced damaged cells, weakening the level of reactive oxygen species in damaged cells. Overall, this study provided a green and high-efficient strategy for extracting phenolic compounds with great antioxidant activities from Q. dentata leaves.

Deep eutectic solvents recovery with bipolar membrane electrodialysis in biorefinery: An economic study

The complex composition and shortage of recycle technology restricted application of deep eutectic solvents (DES). Bipolar membrane electrodialysis has been proven efficient for DES recovery in biorefinery. A comprehensive economic study was essential prior to industrial recovery of DES with bipolar membrane electrodialysis (BMED). An economic study of the BMED-based recovery technique was performed by ascertaining influence of major factors on DES recovery charge with sensitivity analysis. Recovery charge of three representative types of DES was found to be changed within 0.83–1.66 $/Kg (choline chloride-ethylene glycol), 1.60–3.88 $/Kg (lactic acid-ethylene glycol), and 1.21–2.44 $/Kg (choline chloride-urea) as each factor altered in the control. Proportion of annual operating duration and loan duration displayed a negative correlation with the total recovery charge of DES. Multiple of membrane price, factor of membrane facility charge, factor of ancillary facility charge, factor of annual maintaining charge, annual reduction of recovery ratio, annual increase of recovery energy consumption, and annual interest rate of loan showed a positive relationship with the recovery charge. Total DES recovery charge increased within 6.0 %–6.4 % when heterogeneous ion-exchange membranes were employed in BMED facility instead of homogeneous ion-exchange membranes. This study verified the economic virtue of BMED-based DES recovery strategy in biorefinery.

Ultra-low viscosity betaine hydrochloride-formic acid deep eutectic solvent for leaching critical metals from spent NCM lithium-ion batteries

With the rapid development of the electric vehicle market and increasing demand for lithium-ion batteries (LIBs), spent LIBs recycling has attracted extensive attention worldwide. Being environmentally friendly, deep eutectic solvents (DESs) have great potential for critical metal recycling from spent LIBs. In this study, a new type of DES, consisting of betaine hydrochloride (BeCl) and formic acid (FA) in a 1BeCl:9FA molar ratio, was designed to leach critical metals from spent LIBs cathode materials. The study found that the as-prepared DESs exhibited extremely low viscosities and strong coordination abilities, which are suitable for metal leaching. By properly regulating and controlling the leaching parameters, the Li, Mn, Co, and Ni leaching efficiencies from spent LiNi0.8Co0.1Mn0.1O2 LIBs reached 98.03, 96.01, 94.19, and 92.35%, respectively, whereas those of critical metals were all > 99.5% from either LiCoO2 or LiMn2O4. The leaching kinetics revealed that the leaching process was controlled by the interfacial chemical reaction, and the leaching mechanism indicated that the highly efficient critical metal leaching was the result of the strong coordination capacity (Cl-), acidity (H+), and reduction capacity (FA) synergistic effect in the DES. This study provides a novel, environmentally friendly, and efficient strategy for critical metals recovery from spent LIBs.

Facile synthesis of DES-based functionalized Polyaniline@Fe3O4 magnetic microspheres for continuous and efficient dye removal: Properties and mechanism

Dyes are organic compounds that are necessary to impart color to substrates. Because methyl orange (MO) and methylene blue (MB) are difficult for the environment to biodegrade, it is critical that dyes be recycled quickly and efficiently. Herein, oxidation was used to create polyaniline@Fe3O4 nanorods (PANI@Fe3O4). Then, different types of deep eutectic solvents (DESs) were grafted to prepare several novel adsorption materials for green DESs-based magnetic nanomicrospheres (DESs-PANI@Fe3O4). The grafting of DESs not only increased the BET surface area (65.24 m2/g) of the adsorbent, provide a channel for rapid adsorption and efficient mass transfer of pollutants, but also provided abundant functionalized active sites (O-H, C = O, NH+) for efficient dye removal. Comparison of FTIR and XPS spectra before and after adsorption showed that specific functional groups (–OH, –NH2, –COOH) and functional chemical bonds (N-H, C-O, O-H) played an important role in rapid and effective dye removal. When grafted with ChCl-Lac as a green solvent, the adsorption capacity of the resulting ChCl-Lac-PANI@Fe3O4 for MO and MB dyes reached to 912.71 and 473.95 mg/g, respectively in a few minutes. Density functional theory (DFT) result showed that the adsorption was mainly promoted through π-π interaction, hydrogen bonding, and van der Waals interaction. In conclusion, DESs-PANI@Fe3O4 prepared by a facile strategy has the ability to remove dyes from wastewater continuously and efficiently, which provides a new concept for the industrial application of green DESs-based magnetic nanosphere adsorbent.

Extraction and separation of astaxanthin with the help of pre-treatment of Haematococcus pluvialis microalgae biomass using aqueous two-phase systems based on deep eutectic solvents

The microalgae Haematococcus pluvialis are the main source of the natural antioxidant astaxanthin. However, the effective extraction of astaxanthin from these microalgae remains a significant challenge due to the rigid, non-hydrolyzable cell walls. Energy savings and high-efficiency cell disruption are essential steps in the recovery of the antioxidant astaxanthin from the cysts of H. pluvialis. In the present study, H. pluvialis microalgae were first cultured in Bold's Basal medium under certain conditions to reach the maximum biomass concentration, and then light shock was applied for astaxanthin accumulation. The cells were initially green and oval, with two flagella. As the induction time increases, the motile cells lose their flagellum and become red cysts with thick cell walls. Pre-treatment of aqueous two-phase systems based on deep eutectic solvents was used to decompose the cell wall. These systems included dipotassium hydrogen phosphate salt, water, and two types of deep eutectic solvents (choline chloride–urea and choline chloride–glucose). The results of pre-treatment of Haematococcus cells by the studied systems showed that intact, healthy cysts were significantly ruptured, disrupted, and facilitated the release of cytoplasmic components, thus facilitating the subsequent separation of astaxanthin by liquid–liquid extraction. The system containing the deep eutectic solvent of choline chloride–urea was the most effective system for cell wall degradation, which resulted in the highest ability to extract astaxanthin. More than 99% of astaxanthin was extracted from Haematococcus under mild conditions (35% deep eutectic solvent, 30% dipotassium hydrogen phosphate at 50 °C, pH = 7.5, followed by liquid–liquid extraction at 25 °C). The present study shows that the pre-treatment of two-phase systems based on deep eutectic solvent and, thus, liquid–liquid extraction is an efficient and environmentally friendly process to improve astaxanthin from the microalgae H. pluvialis.

Comparative analysis of photo-fermentation hydrogen production from pretreated corn stover by deep eutectic solvents

To compare the pretreatment effect of deep eutectic solvents (DESs) on corn stover, three types of DESs (acid, neutral, and alkaline) were used to pretreat corn stover, and their effects on lignin removal were investigated. Then the performance of photo-fermentation hydrogen production (PFHP) using DESs pretreated corn stover was compared and analyzed. The results showed that acid DESs had the best lignin removal efficiency, and the lignin removal percentages of choline chloride/formic acid (ChCl/Fac) and choline chloride/oxalate (ChCl/Oac) were 64.7% and 65.6%, respectively. The alkaline DESs had the second highest removal of lignin, while the neutral DESs had a poor effect on lignin removal. The comparison of hydrogen production indicated that the corn stover pretreated with ChCl/Oac had the best hydrogen production effect. In conclusion, the DESs pretreatment can obviously remove the lignin in corn stover, and then improve the hydrogen production capacity and efficiency of photo-fermentation, which provides a potential pretreatment method for the efficient utilization of straw biomass.

Choline-based Deep Eutectic Solvent for Extractive Oxidative Desulfurization of Model Oil

One of the hardest processes encountered by petroleum refining is sulfur elimination from fuel oil. There are many traditional methods executed but they caused drawbacks such as poor selectivity of sulfur compounds and toxic raw materials. Extractive oxidative desulfurization (EODS) caught the interest of researchers due to high selectivity of sulfur compounds and great desulfurization. Currently, researchers are investigating the use of ionic liquids (ILs) as green extractant, unfortunately they are expensive. This research is proposing and comparing the use of cheap biodegradable solvents called deep eutectic solvents (DESs), as extractants in removing sulfur from fuel oil. The DESs are synthesized through a combination of choline chloride - orcinol and choline chloride - ethylene glycol, and their structure is confirmed through FTIR. Their thermal properties are characterized by DSC and TGA. Their desulfurization performance is evaluated by type of DESs, different ratios of DES and model oil, different ratios of oxidant and sulfone and various temperatures which these factors are found to influence the result. The optimum conditions are found to be at 1:1 for DES and model oil ratio, 4 for O/S ratio and temperature at 85 °C with the extraction efficiency of 99.98%. In conclusion, this DES has high potential to be the cheap green alternative to the conventional extractant for extractive oxidative desulfurization process.

Deep eutectic solvent extraction combined with magnetic bead ligand fishing for identification of α-glucosidase inhibitors from Pueraria lobata.

In this study, a deep eutectic solvent (DES) extraction combined with a magnetic bead ligand affinity analytical method was developed and used for α-glucosidase inhibitor identification from Pueraria lobata. Several critical parameters affecting the analysis performance, including the type of DES, molar ratio, water amount, pH, salt concentration, and volume of DES, were investigated. The selected analytical sample preparation conditions were as follows. The composition of DES is choline chloride-1,4-butanediol (1:3), the water content is 40%, pH is 7.0 and the volume of extraction solution is 2 mL. The obtained sample extraction solution was analyzed directly using α-glucosidase immobilized magnetic beads (GMBs). Three α-glucosidase inhibitors in Pueraria lobata, including puerarin, daidzin, and daidzein, were identified. Luteolin was used as a positive control to evaluate the method's selectivity. Results showed it could selectively bond to the GMBs in the DES. As the affinity analysis was performed directly in a DES, the solution-removing process could be avoided. The intra-day and inter-day precisions of the method are 5.21% and 6.38%, respectively. The solvent amount was 1/50-1/2000 of that used in traditional methods.

Optimization of Deep Eutectic Solvents Enables Green and Efficient Cryopreservation.

Cryopreservation presents significant opportunities for biomedical applications including cell therapy, tissue engineering, and assisted reproduction. Dimethyl sulfoxide (DMSO), the most commonly used cryoprotectant (CPA), can be added to cells to prevent cryogenic damage. However, the toxicity of cryoprotectants restrains its further development in many areas with safety concerns such as clinical treatment. Therefore, the development of low-toxicity cryoprotectants is essential for medical research. This work reports deep eutectic solvents (DES) as naturally biocompatible osmoprotectants for green and efficient cryopreservation of human umbilical cord mesenchymal stem cells (HuMSC), which may be an ideal alternative to DMSO. The six types of DESs were explored for thermal properties, toxicity, and permeability in cells. Raman spectroscopy and viscosity studies showed that DES exhibited an improved hydrogen-bonding system as the temperature decreased. By optimizing the freezing process (cooling rate, incubation time, and loading procedure) of DES, the viability of mouse embryonic fibroblast cells (NIH-3T3) after thawing was significantly improved. The HuMSC were successfully preserved with no significant difference (p > 0.05) in cell viability (94.65%) after thawing compared with DMSO, which preserved the cell differentiation function and improved the cell proliferation rate. The mechanism of DES in cryopreservation was investigated, and it was found that DES could bind water molecules and effectively inhibit the growth of ice crystals during ice recrystallization, reducing mechanical damage to cells. This study highlights the excellent performance of DES as a low-toxicity CPA for stem cell preservation, which may be a significant advance for future clinical cell therapy.

Facilitating enzymatic hydrolysis efficiency of rape straw by pretreatment with a novel glycerol-based deep eutectic solvent

Deep eutectic solvent (DES) pretreatment plays an indispensable role in destroying the natural anti-degradation barrier structure of lignocellulose. Here, the cetyltrimethylammonium bromide and glycerol were used to synthesize novel DES and introduced to the pretreatment process to facilitate the enzymatic hydrolysis efficiency of rape straw (RS). The results showed that the delignification and xylan removal could extremely reach 46.1% and 52.7% under optimal conditions (molar ratio of 1:6, 200 °C, 90 min), respectively. It also resulted in 171.4 mg/g higher accessibility, 7.2% higher crystallinity, and 122.3 m2/g lower lignin surface area in RS concerning morphological changes of deconstructed and porous cell wall structure. Ultimately, the reducing sugar yield of RS was increased from 27.4% to 67.9% after pretreatment with this type of DES. This study exploited a novel DES for facilely reducing the recalcitrance of lignocellulose and a promising process for efficient saccharification using renewable biomass.