Macroporous Resin Research Articles

Separation process characteristics of phenolic compounds from organic purple‐fleshed sweet potatoes (Ipomoea batatas L.) leaves using macroporous resins

AbstractCurrent trends have been noticed in to study of unedible parts of food as sources of phytochemicals or as ingredients in order to develop new uses for discarded materials and to promote sustainability. This study aimed to evaluate the performance of six macroporous resins (XAD 16, XAD 7HP, XAD 2, XAD 4, DAX 8, and XAD 1180 N) in purification of phenolic compounds from organic purple‐fleshed sweet potatoes. Static adsorption and desorption showed that XAD16 and XAD7HP had the highest adsorption and desorption ratio and recovery yield. The process temperature did not affect the adsorption capacity of XAD16. However, XAD7HP showed higher adsorption capacity when performed at 30°C, compared with 40 and 50°C. The process of equilibrium adsorption isotherms for phenolics was better described using Freundlich isotherm model. Dynamic adsorption process on XAD7HP resin showed that phenolic compounds in the water extracts of leaves started to break through after 4.5 bed volumes of extract was loaded. The purification of phytochemicals using adsorption is an alternative to replace organic solvents and provide a safety process for industrial application.Practical ApplicationsRecently, phenolic compounds have been explored due to their significant biological and antioxidant properties; phenolic compounds are also related to decreasing the risk of cardiovascular diseases, cancer, oxidative stress, diabetes, fatness, cancer, and several degenerative diseases. In addition, there is the potential use of phenolic compounds such as anthocyanin as safe colorimetric pH indicators in innovative packaging due to the relationship between levels of pH and anthocyanin colors. Therefore, using advanced processing technologies, phenolic compound purification can be essential for many applications related to food safety, quality, nutrition, and food waste. Furthermore, purified phenolic compounds can be used as raw materials in the pharmaceutical area and food industries.

Recovery and separation of glycyrrhizic acid from Natural Deep Eutectic Solvent (NADES) extract by macroporous resin: adsorption kinetics and isotherm studies

Natural Deep Eutectic Solvents (NADESs) have emerged as a green and sustainable alternative to conventional organic solvents to extract bioactive compounds. However, the recovery of bioactive compounds from the NADES extracts is challenging, restricting their large-scale applications. The present work investigated the recovery of glycyrrhizic acid (GA) from choline-chloride/lactic acid NADES extract using macroporous resins. GA possesses a wide spectrum of biological activities, and it is extracted from the well-known herb Glycyrrhiza glabra. During resin screening, DIAIONTM SP700 showed high adsorption and desorption capacities. The adsorption kinetics study demonstrated that the adsorption of GA on SP700 followed Pseudo First-order kinetic model. Moreover, the adsorption behaviors were elucidated by the Freundlich isotherm using a correlation coefficient based on a static adsorption study at different temperatures and pH. Furthermore, the thermodynamic parameters, for instance, the change of Gibbs free energy (ΔG*), entropy (ΔS*), and enthalpy (ΔH*), showed that the adsorption process was spontaneous, favorable and exothermic. In addition, the sample after macroporous resin treatment, which is enriched with GA exhibited good anticancer potential analyzed by SRB assay. The regenerated NADES solvent was recycled twice, keeping more than 90% extraction efficiency, indicating good reusability of NADES in the GA extraction process by using macroporous resin.

Tong Sai granule improves AECOPD via regulation of MAPK-SIRT1-NF-κB pathway and cellular senescence alleviation

Ethnopharmacological relevanceTong Sai granule (TSG) a traditional Chinese medicine, are used to treat acute exacerbations of chronic obstructive pulmonary disease (AECOPD). Cellular senescence is considered the mechanism underlying AECOPD progression. Aim of the studyThis study aimed to investigate the therapeutic mechanisms of TSG in an AECOPD rat model (established using cigarette smoke exposure and bacterial infection) and focused on the inhibition of cellular senescence in vivo and in vitro. Materials and methodsHistological changes and levels of inflammatory cytokines, matrix metalloproteinases (MMPs), p53, and p21 were determined. A cellular senescence model was established by challenging airway epithelial cells with cigarette smoke extract (CSE) and lipopolysaccharide (LPS). Quantitative PCR, western blotting, and immunofluorescence were used to measure mRNA and protein levels. Additionally, UPLC-Q-Extractive-Orbitrap MS analysis, network analysis, and transcriptomics were used to analyze the potential compounds and molecular mechanisms of TSG. ResultsThe results showed that oral administration of TSG significantly reduced the severity of AECOPD in rats by ameliorating lung function decline and pathological injuries and increasing the levels of C-reactive protein and serum amyloid A, two well-known proinflammatory mediators of the acute phase response. Oral TSG administration also decreased the expression levels of proinflammatory cytokines (e.g., IL-6, IL-1β, and TNF-α), MMPs (e.g., MMP-2 and MMP-9), critical regulators of senescence such as p21 and p53, and the apoptotic marker γH2AX, all of which are factors in cellular senescence in lung tissue. TSG4 was isolated from TSGs using macroporous resin and found to significantly suppress cellular senescence in CSE/LPS-induced bronchial epithelial cells. Furthermore, 26 of 56 compounds identified in TSG4 were used to predict 882 potential targets. Additionally, 317 differentially expressed genes (DEGs) were detected in CSE/LPS-treated bronchial epithelial cells. Network analysis of the 882 targets and 317 DEGs revealed that TSG4 regulated multiple pathways, among which the mitogen-activated protein kinase–sirtuin 1–nuclear factor kappa B (MAPK–SIRT1–NF-κB) pathway is important in terms of antisenescent mechanisms. Moreover, in CSE/LPS-induced bronchial epithelial cells, p-p38, p-ERK1/2, p-JNK, and p-p65 levels were increased and SIRT1 levels were decreased after TSG4 treatment. Additionally, oral TSG administration decreased p-p38 and p-p65 levels and increased SIRT1 levels in the lung tissues of AECOPD model rats. ConclusionCollectively, these results indicate that TSGs ameliorate AECOPD by regulating the MAPK–SIRT1–NF-κB signaling pathway and subsequently suppressing cellular senescence.

Structural Characteristics and Immunomodulatory Effects of Melanoidins from Black Garlic.

Melanoidins are considered to have several biological activities. In this study, black garlic melanoidins (MLDs) were collected using ethanol solution extraction; 0%, 20%, and 40% ethanol solutions were used for chromatography. Three kinds of melanoidins were produced by macroporous resin, named MLD-0, MLD-20, and MLD-40. The molecular weight was determined, and the infrared and microscopic structures were studied. In addition, Balb/c mice were induced with cyclophosphamide (CTX) to establish an immune deficiency model to evaluate the immune efficacy of black garlic melanoidins (MLDs). The results showed that MLDs restored the proliferation and phagocytosis ability of macrophages, and the proliferation activity of B lymphocytes in the MD group was 63.32% (♀) and 58.11% (♂) higher than that in the CTX group, respectively. In addition, MLDs alleviated the abnormal expression of serum factors such as IFN-γ, IL-10, and TNF-α. 16SrDNA sequencing of intestinal fecal samples of mice showed that MLDs changed the structure and quantity of intestinal flora, and especially that the relative abundance of Bacteroidaceae was significantly increased. The relative abundance of Staphylococcaceae was significantly reduced. These results showed that MLDs improved the diversity of intestinal flora in mice, and improved the adverse state of immune organs and immune cells. The experiments confirm that black garlic melanoidins have potential value in immune activity, which provides an important basis for the development and utilization of melioidosis.

Highly efficient degradation of ofloxacin and diclofenac by composite photocatalyst aloe-emodin/PMMA.

Photocatalysis is one of the most effective methods to remove pollutants from water. Photocatalyst is the core of photocatalysis. The composite photocatalyst combines the photosensitizer with the support and uses the photosensitivity of the photosensitizer and the stability and adsorption of the support to achieve efficient and rapid degradation of pharmaceuticals in water. In this study, natural aloe-emodin with π-conjugated structure was used as photosensitizer to react with macroporous resin polymethylmethacrylate (PMMA) under mild conditions to prepare composite photocatalysts AE/PMMAs. The photocatalyst underwent photogenerated electron migration under visible light to form •O2- and holes with high oxidation activity, which could realize efficient photocatalytic degradation of ofloxacin and diclofenac sodium and showed excellent stability, recyclability and industrial feasibility. This research has developed an efficient method of composite photocatalyst and realized the application of a natural photosensitizer in pharmaceutical degradations.

Optimization of Extraction and Separation Process of Notoginsenoside Fc from Panax notoginseng Leaves.

Response surface methodology (RSM) was used to determine the optimal conditions for ultrasound-assisted extraction (UAE) of Notoginsenoside Fc (Fc) from panax notoginseng leaves. The experiment utilized a Box-Behnken design (BBD) and separation conditions were optimized. The optimum extraction conditions were as follows: extraction time = 1.5 h, ethanol concentration = 86%, liquid-to-solid ratio = 19:1. The experimentally obtained values were in accordance with the values predicted by the RSM model. We determined that the RSM model was able to successfully simulate the optimal extraction of Fc from the leaves. Further, Fc was enriched from Panax notoginseng through nine macroporous resins, and HPD-100 macroporous resins were selected for preliminary enrichment of Fc due to its economic costs and benefits. Subsequently, octadecyl silane (ODS) column chromatography was used to improve the purity of Fc to over 90% after separation by ODS column chromatography. Fc with a purity greater than 95% can be obtained by recrystallization. This is the first study that has focused on the extraction and enrichment of Fc from Panax notoginseng leaves using macroporous resin combined with ODS column chromatography, which provides the possibility for further application of Fc.

Efficient adsorption of alginate oligosaccharides by ion exchange resin based on molecular simulation and experiments

Alginate oligosaccharides (AOS) with low polymerization have gained considerable attention due to their unique physiological activities. However, the lack of understanding regarding the mechanism of action for resin selection and optimization of separation processes has impeded their precise chromatographic separation and large-scale production. Here, the adsorption–desorption characteristics of AOS on the resins with varying solid phase composition, including backbones, functional groups, crosslinking degrees, and counterions resin structures, were analyzed using simulations and experiments. The simulation results revealed that the structural differences of AOS are characterized by their electrostatic potential and lowest unoccupied molecular orbital energy level. Based on molecular simulations, we predicted that the basic anion resin with a styrene backbone would be suitable for AOS separation. Subsequently, we constructed SM-7Cl resin based on the simulation results and performed static adsorption experiments to verify the prediction. SM-7Cl resin demonstrated noteworthy adsorption–desorption performance for AOS, with an adsorption capacity of 471.2 mg/g and a desorption rate of 89.45%. The fitting adsorption isotherm was consistent with the Freundlich model, indicating that the adsorption proceeded spontaneously. The equilibrium times for AOS adsorption on the gel-type resin and the macroporous resin, which both followed a pseudo-second-order kinetic model, were 30 min and 60 min, respectively. This study provides optimized chromatographic media and separation processing that can be implemented for the amplification of chromatographic separation in AOS production.

Preparation of a novel high-performance lignin-based anionic adsorption resin for efficient removal of Cr(VI) in aqueous solutions

To remove Cr(VI) in water, a novel lignin-based anionic adsorption resin epichlorohydrin cross-linking lignin grafted by diethylenetriamine (E-DAL) was prepared by the direct cross-linking and curing of alkali lignin grafted by diethylenetriamine in aqueous solutions. Under the determined optimum synthesis conditions, E-DAL with higher nitrogen (7.46%) and lignin (32.78%) contents was obtained. Structural and physicochemical measurement results showed E-DAL was a macroporous resin, having a regular connected pore structure with porosity of 67.48% and pore size of 615.6 nm, also strong hydrophilicity, excellent acid-alkaline resistance and thermal stability. Adsorption experiment results indicated the adsorption isotherm of E-DAL to Cr(VI) was well-described by Langmuir model. E-DAL showed a higher adsorption capacity to Cr(VI), and the fitted maximum adsorption capacity reached up to 775.2 mg/g. Pseudo-second-order model could fit this adsorption process well, suggesting its chemisorption characteristics. The calculated thermodynamic parameters indicated a spontaneous and endothermic adsorption of E-DAL to Cr(VI). Dynamic column adsorption results showed E-DAL could completely remove Cr(VI) in wastewater. This whole preparation process only used a very small amount of cheaper amination agent and was relatively low-cost. This work provided efficient technical supports for the structural design of high-performance lignin-based anionic adsorption materials in water treatment field.

Extractive adsorption of 1,3-propanediol on a novel polystyrene macroporous resin enclosing medium and long-chain alcohols as extractant

Extractive adsorption is an integrated separation method employing a novel resin with both particle and liquid characteristics in terms of adsorption and extraction. In this study, the novel extractive adsorption polystyrene-divinylbenzene (PS-DVB) macroporous resin was synthesized by suspension polymerization, in which n-octanol (OL-PS-DVB) or mixed alcohols of n-octanol, undecyl alcohol, and tetradecyl alcohol (MA-PS-DVB) were added as porogen and enclosed in the resin skeleton after the reaction. The characterization of the two novel resins of OL-PS-DVB and MA-PS-DVB showed that they have large specific surface areas of 48.7 and 17.4 m2/g, respectively. Additionally, the two synthesized resins have much higher static adsorption capacities of 1,3-propanediol (511 and 473 mg/g) and dynamic adsorption capacities (312 and 267 mg/g) than traditional resins, because extractants enclosed in the resin can increase the adsorption capacity. Through Langmuir equation, the theoretical static maximum adsorption capacity of the mixed alcohols resin is 515 mg/g at 298 K and Gibbs free energy change of adsorption was -3781 J/mol, indicating that the adsorption process was spontaneous. In addition, the sorbent concentration effect in the resin was generated at high 1,3-propanediol (1,3-PDO) concentrations. The fitting of the Flocculation model can reveal that there is a possible relation between adsorption and flocculation. Compared to OL-PS-DVB, MA-PS-DVB showed better performance in the recovery yield of 1,3-PDO and other byproducts, the removal rates of the inorganic salt and protein, and the efficiency of recycled resin. For MA-PS-DVB, the recovery of 1,3-PDO, butyrate acid, acetic acid, and residual glycerol was 97.1%, 94.7%, 93.3%, and 90.3%, respectively. Simultaneously, the resin of MA-PS-DVB could remove 93.8% of inorganic salts and 90.9% of proteins in the concentrated fermentation broth. The two synthesized resins of OL-PS-DVB and MA-PS-DVB still had 90% or 92% of capacity for extractive adsorption of 1,3-propanediol after 10 times of recycling, which exhibited potential application in the separation of 1,3-propanediol from fermentation broth.

Immobilized KDN Lipase on Macroporous Resin for Isopropyl Myristate Synthesis

Free enzymes often face economic problems because of their non-repeatability and variability, which limit their application in industrial production. In this study, KDN lipase was immobilized with the macroporous resin LXTE-1000 and glutaraldehyde. The optimal conditions of enzyme immobilization were defined by a single factor experiment and response surface methodology (RSM). The concentration of the cross-linking agent glutaraldehyde was 0.46% (v/v), the cross-linking temperature was 25.0 °C, and the cross-linking time was 157 min. The enzyme activity of the immobilized KDN lipase after adsorption/cross-linking was 291.36 U/g, and the recovery of the enzyme activity was 9.90%. The optimal conditions for the synthesis of isopropyl myristate were catalyzed by the immobilized KDN lipase in a solvent-free system: immobilized enzyme 53 mg, reaction temperature 36.1 °C, myristic acid 228.4 mg, isopropanol 114 µL, and reaction time 18 h. The yield of isopropyl myristate was 66.62%. After ten cycles, the activity of the immobilized KDN lipase preserved more than 46.87% of its initial enzyme activity, and it demonstrated high tolerance to solvents compared to free KDN lipase.

Extraction, Purification, and Component Identification of Monoterpene Glycosides from Paeonia suffruticosa Seed Meal.

Paeonia suffruticosa (P. suffruticosa) seed meal is a byproduct of P. suffruticosa seed processing, which contains bioactive substances such as monoterpene glycosides, and has not been effectively utilized at present. In this study, monoterpene glycosides were extracted from P. suffruticosa seed meal using an ultrasound-assisted ethanol extraction process. The monoterpene glycoside extract was then purified by macroporous resin and identified using HPLC-Q-TOF-MS/MS. The results indicated the following optimal extraction conditions: ethanol concentration, 33%; ultrasound temperature, 55 °C; ultrasound power, 400 W; liquid-material ratio, 33:1; and ultrasound time, 44 min. Under these conditions, the yield of monoterpene glycosides was 121.03 mg/g. The purity of the monoterpene glycosides increased from 20.5% (crude extract) to 71.2% (purified extract) when using LSA-900C macroporous resin. Six monoterpene glycosides (oxy paeoniflorin, isomaltose paeoniflorin, albiflorin, 6'-O-β-D-glucopyranoside albiflorin, paeoniflorin, and Mudanpioside i) were identified from the extract using HPLC-Q-TOF-MS/MS. The main substances were albiflorin and paeoniflorin, and the contents were 15.24 mg/g and 14.12 mg/g, respectively. The results of this study can provide a theoretical basis for the effective utilization of P. suffruticosa seed meal.

Highly selective removal of Technetium-99 using imidazolium-based macroporous anion exchange resins

Technetium-99 (99Tc), as a β-emitting radionuclide, is one of the main components of nuclear waste. The fast environmental mobility of 99TcO4- makes it a great threat to the environment and human beings. Although some adsorption materials have been developed to remove 99TcO4- from the nuclear wastewater, the low selectivity and poor stability under acid and radiation conditions limit their actual application. In this work, an N-methylimidazolium modified macroporous anion exchange resin (PMiMCl) was developed for the highly selective removal of 99TcO4-. Batch adsorption experiments demonstrated that the PMiMCl resin exhibited high adsorption capacity (Re(VII), 677.21 mg g−1) in a wide pH range (3–7). The resin showed high stability after acid (5 mol L-1 HCl), alkali (5 mol L-1 NaOH) and radiation (1000 KGy 60Co γ) treatment and the remove ability was little influenced. More importantly, in the presence of high concentration of competing anions, the removal efficiency of 99TcO4- with PMiMCl resin can also reach to 97.64%, which was much higher than those treated by commercial resins (93.02% for ZGANR170 and 93.10% for IRN78), demonstrating its good selectivity. The density functional theory calculations revealed that the high selectivity was attributed to the strongest interaction of imidazole cation in PMiMCl resin with 99TcO4- anion compared with NO3−, SO42− and Cl− anions. These superior features coupled with low cost and feasible for large scale production and application make PMiMCl resin great potential for 99Tc removal in nuclear wastewater.

Rehmannia glutinosa Polysaccharides: Optimization of the Decolorization Process and Antioxidant and Anti-Inflammatory Effects in LPS-Stimulated Porcine Intestinal Epithelial Cells.

Polysaccharide decolorization has a major effect on polysaccharide function. In the present study, the decolorization of Rehmannia glutinosa polysaccharides (RGP) is optimized using two methods-the AB-8 macroporous resin (RGP-1) method and the H2O2 (RGP-2) method. The optimal decolorization parameters for the AB-8 macroporous resin method were as follows: temperature, 50 °C; macroporous resin addition, 8.4%; decolorization duration, 64 min; and pH, 5. Under these conditions, the overall score was 65.29 ± 3.4%. The optimal decolorization conditions for the H2O2 method were as follows: temperature, 51 °C; H2O2 addition, 9.5%; decolorization duration, 2 h; and pH, 8.6. Under these conditions, the overall score was 79.29 ± 4.8%. Two pure polysaccharides (RGP-1-A and RGP-2-A) were isolated from RGP-1 and RGP-2. Subsequently, their antioxidant and anti-inflammatory effects and mechanisms were evaluated. RGP treatment activated the Nrf2/Keap1 pathway and significantly increased the activity of antioxidant enzymes (p < 0.05). It also inhibited the expression of pro-inflammatory factors and suppressed the TLR4/NF-κB pathway (p < 0.05). RGP-1-A had a significantly better protective effect than RGP-2-A, likely owing to the sulfate and uronic groups it contains. Together, the findings indicate that RGP can act as a natural agent for the prevention of oxidation and inflammation-related diseases.

Separation, structural identification and antibacterial activity of pectin oligosaccharides derived from seed melon

In this study, the pectin of waste seed melon peel in Xinjiang was used as raw material to prepare seed melon pectin oligosaccharide (Sm-POS). The separation and purification of Sm-POS were carried out by HPD-750 macroporous resin chromatography column and gel chromatography to further study the molecular structure of its active component with antibacterial effect by FT-IR, NMR, and LC/MS.The antibacterial activity and mechanism of the Sm-POS active component were investigated by inhibition zone experiment, minimum inhibitory concentration determination, cell growth curve determination, scanning electron microscopy, and flow cytometry analysis. Results showed that Sm-POS-2 was an oligosaccharide composed of two galacturonic acids, one glucose, one arabinose, and one xylose. It showed good antibacterial activity and suppressed the growth of E. coli and S. aureus at minimum inhibitory concentrations (MIC) of 25.0 and 50.0 g/L, respectively. The inhibitory effect of Sm-POS on E. coli and S. aureus was mainly due to cell membrane contraction or rupture, leading to the apoptosis or necrosis of bacterial cells.

Production of Epoxidized Rubber Seed Oil via Lipase-Catalyzed Epoxidation

Rubber seeds are residuals from rubber plantations containing oils. Epoxidized rubber seed oil (ERSO) was produced from rubber seed oil under different conditions withacetic acid as an oxygen carrier and hydrogen peroxide as an oxygen donor. A lipase B immobilized on macroporous acrylic resin beads was used as a biocatalyst. The lipase biocatalyst was used to optimize the epoxidation process at a temperature of 65 C and a reaction period of 18 h. Under these conditions, ERSO with the highest epoxidation percentage of 81.63 % and a low iodine value of 4.43 g iodine/kg sample was obtained. The key functional groups of ERSOs were investigated by Fourier transform infrared spectroscopy (FTIR), in which the FTIR spectra showed the oxirane ring of ERSOs. The proton nuclear magnetic resonance (1H-NMR) analyses confirmed the decrease of the peak of the double bond in rubber seed oil and the existence of an epoxidized ring peak in ERSOs. These results showed that ERSOs were successfully synthesized from rubber seed oil.

Terpenoids of quinoa bran suppresses colorectal cancer by inducing cell apoptosis

Colorectal cancer (CRC) is one of the most common malignant tumors worldwide, occurring in the colon or rectum portion. Quinoa is a dicotyledonous plant, and the quinoa bran is the outer seed coat of quinoa. Functional molecules in plants play an important role in the treatment and alleviation of chronic diseases. In this study, quinoa bran was used as the raw material. The active components with an anti-colorectal cancer effect were extracted by acetone and separated with an AB-8 macroporous resin column, which was further identified as terpenoids by liquid-mass spectrometry (LMS), named Quinoa bran terpenoids (QBT). The yield of quinoa bran terpenoids was 0.77%. Moreover, the results showed that QBT significantly inhibited the proliferation of colorectal cancer cells DLD-1 and HCT-8 with a concentration gradient dependent manner. Respectively, the IC50 values of DLD-1 and HCT-8 cells were 0.42 ± 0.02 and 0.54 ± 0.05 mg/mL. Further studies showed that QBT upregulated apoptosis-related proteins such as activated-caspase-3, 8, and 9. In addition, QBT decreased mitochondrial membrane potential, promoted the expression of the pro-apoptotic protein Bax, and inhibited the anti-apoptotic protein Bcl-2. The experiments showed that QBT significantly repressed the growth of tumors in nude mice. In conclusion, these results indicated that QBT largely inhibits the development of colorectal cancer to large extent through upregulation of caspase-3, 8, and 9 and reduction of mitochondrial membrane potential, and has great potential for anti-tumor progression.

Etherification of olefins from catalytic cracking gasoline to increase its octane number

This study explores the etherification of the olefins in the Fluid Catalytic Cracking (FCC) gasoline, without previous separation of isoamylenes fraction. The bench- scale experiment demonstrated that etherification performed with Purolite CT-275, a macroporous polymeric ion-exchange resin, and different alcohols (methanol, bioethanol, isopropanol and 1-butanol) produces significant conversion of olefins, even for the heavier C6-C9, so that overall conversion of olefins reaches 70% in reaction with ethanol and 83% with isopropanol. As a result, the Motor Octane Number of the gasoline increases by up to two valuable units. The optimization of the reactive distillation parameters was performed by simulation in CHEMCAD 8 and a process flow was suggested for the etherification sequence, in the FCC unit.

Extraction and separation characteristic stilbene compounds from pigeon pea leaves using V-type thymol-based natural deep eutectic solvent systems

In this study, a V-type deep eutectic miniature solvent composed of thymol/coumarin was designed based on the principle of similitude compatibility and π-π conjugate effect for the extraction of stilbene structure compounds from pigeon pea leaves. According to Hansen solubility parameter theory, the optimal DES type and composition molar ratio were screened out. The optimal extraction conditions were thymol/coumarin ratio 2:1, ultrasonic power 200 W, ultrasonic time 20 min, liquid-solid ratio 50:1 (mL/g). According to the hydrophobic DES form hydrogen bond position, we found that add a small amount of ammonia solution can effectively destroy DES hydrogen bonding structure, which reduces the target product solubility in the solvent, combined with macroporous resin adsorption process can be quickly and efficiently recycling target component and separation solvent. Through the rotary evaporator to remove water, HBAs and HBDs are recombined to form DES, which can be directly used for secondary extraction. After three cycles of DES, the rate of recovery of DES was over 80%. Moreover, the FT-IR, UV–vis and NMR were applied to investigate physicochemical properties of DES and extraction mechanism. This study provides a new solvent screening idea for the extraction and separation of natural products, and designs a green and sustainable extraction and separation process of natural products, and provides a new idea for the recycling of hydrophobic DES.

Separation and purification of glabridin from a deep eutectic solvent extract of Glycyrrhiza glabra residue by macroporous resin and its mechanism

Glabridin has beneficial antioxidant, anti-inflammatory, and tyrosinase inhibitory activities, with many applications in the pharmaceutical and cosmetics industries. After industrial extraction of glycyrrhizic acid, Glycyrrhiza glabra residue contains abundant glabridin. Glabridin was extracted from Glycyrrhiza glabra residue with a deep eutectic solvent (DES), followed by the recovery of the glabridin by organic solvent extraction, and then partial purification with hydrophobic macroporous resin. Ethyl acetate was the best extraction solvent, with an extraction yield of 91.63 %. Twelve macroporous resins were evaluated and LSA-21 yielded the best recovery of glabridin. Adsorption of glabridin by LSA-21 resin conformed to pseudo-second-order kinetic and Langmuir models. The thermodynamic parameters ΔH (enthalpy change) and ΔG (Gibbs free energy) were both negative, ΔS (entropy change) was positive. These results indicated that LSA-21 resin spontaneously and exothermically adsorbs glabridin to form a monolayer. The optimum conditions for separating and purifying glabridin by LSA-21 resin were 50 % ethanol aqueous solution(v/v) with a concentration of 56.90 µg/mL glabridin at a flow rate of 2 bed-volumes (BV)/h, and elution with 4 BV of ethanol at 2 BV/h, producing a glabridin yield of 97.80 %. The resin could be reused four times and the glabridin yield slightly decreased to 94 %. The overall recovery of glabridin from the DES Glycyrrhiza glabra extract solution after the ethyl acetate and LSA-21 steps was 89.61 %, with a purity of 17.38 %. This approach is an effective method for the recovery and purification of glabridin from a DES extract of Glycyrrhiza glabra residue, which has potential industrial application for producing glabridin and other natural plant products.

Production of antifungal iturins from vegetable straw: A combined chemical-bacterial process

A combined chemical-bacterial process was developed to convert vegetable straw waste to high value antifungal iturins. Straws from three widely cultivated vegetable (cucumber, tomato and pepper) were evaluated as feedstocks for iturin production. Microwave assisted hydrolysis with very dilute acid (0.2% w/w H2SO4) achieved efficient reducing sugar recovery. The high glucose concentration in non-detoxified hydrolysate from pepper straw facilitated the optimal growth of Bacillus amyloliquefaciens strain Cas02 and stimulated the production of iturin. The fermentation parameters were optimised to enhance the iturin production efficiency. The obtained fermentation extract was further purified using macroporous adsorption resin, resulting in an iturin-rich extract that exhibited strong antifungal activity against Alternaria alternata with an IC50 of 176.44 μg/mL. Each iturin homologue was identified using NMR. Overall, 1.58 g iturin-rich extract containing 164.06 mg/g iturins was obtained from 100 g pepper straw, illustrating the great potential of valorising pepper straw via this process.