Purification Process Research Articles

Development of a glutamate-functionalized macroporous cation-exchange matrix for partial purification of lysozyme from chicken egg white

The polymeric monoliths, called cryogels, arouse interest due to their versatility and to be a good alternative for enzyme purification processes. Lysozyme is an enzyme that stands out for its antimicrobial activity and is being used as a preservative in the food industry. This work aimed to produce a new cationic exchange matrix functionalized with monosodium glutamate for partial lysozyme purification of egg white. The structural characteristics of the support delivered were evaluated, presenting an ion exchange capacity (IEC) of 362×10−3 mol Na+. kg−1dry cryogel, zero charge point (PCZ) around pH 6.0, and porosity more significant than 90 %. The FTIR and TGA analyses proved that the modification of the XRD matrix indicated the material's amorphous nature. The hydrodynamic studies showed asymmetry, indicating the pores' non-uniformity and low resistance to flow. The lysozyme was purified from egg white, and a purification factor of 15.11 was obtained. SDS-PAGE electrophoresis analysis indicated high purity of lysozyme, with no other protein bands appearing in the eluted solution, indicating that the adsorbent has high potential for application in lysozyme purification processes.

Application of SUMO fusion technology for the enhancement of stability and activity of lysophospholipase from Pyrococcus abyssi

Application of SUMO fusion technology for the enhancement of stability and activity of lysophospholipase from Pyrococcus abyssi

Extraction of Natural Food Color from Tomato, Carrot and Turmeric

The demand for natural and healthier food products has increased dramatically in recent years due to growing consumer awareness of the impact food has on health as well as evidence of adverse effects from various ingredients, including some additives. This study evaluates the extraction method, solvent effects, precipitation, identification, purification, and lycopene, carotene, and curcumin content from turmeric, carrot, and tomato. Along-side, tomato, carrot, and turmeric samples were subjected to two different extraction and purification processes: solvent extraction for lycopene and carotene, and alkalization for curcumin. The samples were extracted and purified at room temperature (30ºC) and chilled (4ºC) for a period of three weeks. Tomato extracts had lycopene contents ranging from 0.0153 to 0.0362 mg/100g. obtained carotene content, which was then extracted using a solvent in the range of 61.43 to 81.72 mg/100g. The alkalization process produced a curcumin concentration of 91.17 to 110.41 mg/100g. Comparing the ethyl acetate extraction technique to the anti-solvent method, a greater amount of lycopene (red) and carotene (orange) precipitation was obtained. The maximum amount of curcumin precipitation obtained in lower pH solution. Lower pH is important to maintain the stability of curcumin precipitation. The experience of this research work suggested that lycopene from tomatoes, carotene from carrots, and curcumin from turmeric might be an excellent source to meet the increasing need for natural colorants.

Tailored Metal-Organic Frameworks for Water Purification: Perfluorinated Fe-MOFs for Enhanced Heterogeneous Catalytic Ozonation.

An industrially viable catalyst for heterogeneous catalytic ozonation (HCO) in water purification requires the characteristics of good dispersion of active species on its surface, efficient electron transfer for ozone decay, and maximum active species utilization. While metal-organic frameworks (MOFs) represent an attractive platform for HCO, the metal nodes in the unmodified MOFs exhibit low catalytic activity. Herein, we present a perfluorinated Fe-MOF catalyst by substituting H atoms on the metalated ligands with F atoms (termed 4F-MIL-88B) to induce structure evolution. The Lewis acidity of 4F-MIL-88B was enhanced via the formation of Fe nodes, tailoring the electron distribution on the catalyst surface. As a result of catalyst modification, the rate constant for degradation of the target compounds examined increased by ∼700% compared with that observed for the unmodified catalyst. Experimental evidence and theoretical calculations showed that the modulated polarity and the enhanced electron transfer between the catalyst and ozone molecules contributed to the adsorption and transformation of O3 to •OH on the catalyst surface. Overall, the results of this study highlight the significance of tailoring the metalated ligands to develop highly efficient and stable MOF catalysts for HCO and provide an in-depth mechanistic understanding of their structure-function evolution, which is expected to facilitate the applications of nanomaterial-based processes in water purification.

Optimization of ultrasonic pretreatment and analysis of chlorogenic acid in potato leaves

Chlorogenic acid (CA) is an effective ingredient that can strengthen immunity during following the COVID-19 era. The current cost of CA is high owing to its complex purification process and low yield (approximately 2%). In this study, a one-step path orthogonal experiment was designed based on the results from Gauss calculation, which consisted of acidity, coordination, and hydrolysis in molecules. The optimized extraction conditions were 60 ℃, 60 min, 1:20 liquid ratio, and 40% ethanol in a nitrogen atmosphere controlled using a device of our own design, which led to CA yields of up to 6.35% from potato leaves. The purified CA was analyzed using high-performance liquid chromatography, thin-layer chromatography, ultraviolet–visible spectroscopy, and molecular fluorescence. This accurate and reproducible method can not only be used to obtain high yields of CA but can also be used for the quality control of active plant products and their isomers.

Fabrication of Carbon Dots with Singlet Oxygen Generation and Their Potential Photodynamic Therapy Applications.

Due to the unique chemical and biomedical properties of carbon dots (CDs), they have increasingly obtained the attention in many research fields, for example, bioimaging, fluorescence sensing, and drug delivery, etc. Recently, it was found that, under light excitation, CDs can also be exploited as a novel photosensitizer to prepare reactive oxygen species (ROS), which expand their applications in the field of photodynamic therapy for cancer treatment. Nevertheless, the high cost and complex fabrication approach of CDs significantly limit their applications. To address this issue, bottom-up routes usually utilize sustainable and inexpensive carbon precursor as starting materials, employed N,N-dimethylformamide (DMF) or ethanol as an environmental-friendly solvent. Bottom-up approach was energy efficient, and the purification process was relatively simple by dialysis. Therefore, carbon dots (CDs) were facilely fabricated in a one-pot solvothermal process using 1-aminoanthraquinone as a precursor, and their application as photosensitizers for in vitro antitumor cells, especially photodynamic therapy (PDT) was established. Then the photophysical and nanoscale dimensions properties of the fabricated CDs were characterized via TEM, UV-visible, fluorescence, and FT-IR spectroscopy. The synthesized N-doped CDs can easily dissolve in water, possess very low biotoxicity, yellow-light emission (maximum peak at 587nm). More importantly, PDT studies demonstrated that the obtained CDs possess a high singlet oxygen yield of 35%, and exhibit significant phototoxicity to cancer cells upon 635nm laser irradiation. These studies highlight that N-doped CDs can be facilely synthesized from only one precursor, and are a potentially novel theranostic agent for in vivo PDT.

Analysis of the state of the art technologies for the utilization and processing of associated petroleum gas into valuable chemical products

Abstract The problems concerning the insufficient level of associated petroleum gas (APG) processing are discussed. Various models are proposed for the chemical utilization of APG, including the production of synthesis gas, methanol, dimethyl ether, ammonia, as well as the processes of aromatization of hydrocarbons, etc. The possibility of using APG as a fuel for generating electricity is discussed. Attention is paid to the processes of APG purification from sulfur impurities. Difficulties and solutions to the problems of the energy sector of APG utilization are discussed.

Dissolution behavior and thermodynamic study of N-ethyl-2,2-diisopropylbutylamide in fourteen mono solvents by experiments and molecular simulation

N-ethyl-2,2-diisopropylbutylamide (WS-27) is a new cooling agent with a soothing, long-lasting cooling effect, widely used in personal care and cosmetic products. The dissolution behavior of WS-27 in fourteen mono solvents (methanol, ethanol, n-propanol, isopropanol, n-butanol, n-pentanol, methyl acetate, ethyl acetate, isopropyl acetate, propyl acetate, butyl acetate, dichloromethane, cyclohexanone, and acetone) was measured using a dynamic laser monitoring method from 263.15 K to 298.15 K under 101.6 ± 1.2 kPa. In these selected solvents, the solubility of WS-27 increased with increasing temperature. The van't Hoff equation, λh equation, modified Apelblat equation, Wilson model, and NRTL (non-random two-liquid) model were applied to correlate the experimental solubility data of WS-27, and the modified Apelblat equation showed the best-fitting results. In addition, the intermolecular interactions and solvent effect were analyzed using the Hirshfeld surface analysis, molecular electrostatic potential surface analysis, and KAT-LSER model analysis to understand the dissolution behavior of WS-27. The results indicate that the solubility of WS-27 is influenced by multiple factors, and there can be other factors as well. These fundamental data can provide essential information for the crystallization and purification process of WS-27.

UNIFAC PREDICTION OF VAPOR LIQUID EQUILIBRIA INVOLVING GAMMA-VALEROLACTONE DERIVATIVE SYSTEMS

Researchers have studied the hydrogenation of Gamma-Valerolactone (GVL) over Ru/C to produce 2-methyltetrahydrofuran (2-MTHF), a biomass-based platform chemical with potential as a biofuel and green solvent. Other byproducts of this reaction include 2-butanol (2-BuOH), 2-pentanol (2-PeOH), and 1,4-pentanediol (1,4-PDO). In this study, UNIFAC activity coefficient models were used to predict the vapor-liquid equilibrium of several systems included in the process to explain the phase behavior which is important in purification process. The accuracy of the UNIFAC model is tested by comparing the experimental boiling points for the binary system of 2-propanol + 1-butanol and the vapor-liquid equi-librium of the GVL + 2-MTHF system. From this comparison, the Root Mean Square Deviation (RMSD) values for the boiling point measurements are obtained to be 3.153%, and for the liquid and vapor phases in the vapor-liquid equilibrium measurements, the RMSD values are 1.934% and 0.298% respectively. These RMSD values indicate the level of accuracy of the UNIFAC model in representing the experimental data for both boiling point measurements and vapor-liquid equilibrium phase behavior. The prediction results of vapor-liquid equilibrium data for GVL derivative systems showed that the 2-BuOH + 2-MTHF system does form an azeotrope when the mol fraction of 2-BuOH is 0.0031 at 79.780C. The calculation was performed using ChemCAD commercial software for chemical process modeling and simulation

Coupling protein scaffold and biosilicification: A sustainable and recyclable approach for d-mannitol production via one-step purification and immobilization of multienzymes

Enzymatic synthesis of biochemicals in vitro is vital in synthetic biology for its efficiency, minimal by-products, and easy product separation. However, challenges like enzyme preparation, stability, and reusability persist. Here, we introduced a protein scaffold and biosilicification coupled system, providing a singular process for the purification and immobilization of multiple enzymes. Using d-mannitol as a model, we initially constructed a self-assembling EE/KK protein scaffold for the co-immobilization of glucose dehydrogenase and mannitol dehydrogenase. Under an enzyme-to-scaffold ratio of 1:8, a d-mannitol yield of 0.692 mol/mol was achieved within 4 h, 2.16-fold higher than the free enzymes. The immobilized enzymes retained 70.9 % of the initial joint activity while the free ones diminished nearly to inactivity after 8 h. Furthermore, we incorporated the biosilicification peptide CotB into the EE/KK scaffold, inducing silica deposition, which enabled the one-step purification and immobilization process assisted by Spy/Snoop protein-peptide pairs. The coupled system demonstrated a comparable d-mannitol yield to that of EE/KK scaffold and 1.34-fold higher remaining activities after 36 h. Following 6 cycles of reaction, the immobilized system retained the capability to synthesize 56.4 % of the initial d-mannitol titer. The self-assembly co-immobilization platform offers an effective approach for enzymatic synthesis of d-mannitol and other biochemicals.

Past, present and future of glycolipids from Ustilaginaceae – A review on cellobiose lipids and mannosylerythritol lipids

AbstractThe glycolipids cellobiose lipids (CL) and mannosylerythritol lipids (MEL) are biosurfactants mainly synthesized by microorganisms of the Ustilaginaceae family. They have a large structural diversity, varying in their sugar moieties and the attached fatty acids, resulting in a prospectively broad range of applications. This literature review provides a detailed overview of known microbial producers of CL and MEL, and their respective metabolic pathways that result in different molecular structures. Further, current advances in the aerobic fermentative synthesis of the glycolipids and their purification methods are illustrated. All influencing factors identified to date with regard to the fermentation are highlighted in detail: For CL synthesis usually hydrophilic carbon sources are used as substrate, whereas hydrophobic carbon sources are usually metabolized to MEL. Nitrogen limitation was described as a major trigger for glycolipid synthesis and an acidic pH range was favored for increased CL production. An overview of applied fermentation parameters in recent publications (e.g., substrate‐concentrations, feeding approaches) demonstrates the future potential of CL and MEL production optimization. Foaming during fermentation is either combated or exploited by foam fractionation as the first purification step. The current purification processes focus on solvent extractions and chromatography in the laboratory scale and a need for development was identified for future scale‐up. Finally, environmental hotspots during CL and MEL production are presented and future optimization potentials are highlighted.

Promising Application, Efficient Production, and Genetic Basis of Mannosylerythritol Lipids

Mannosylerythritol lipids (MELs) are a class of glycolipids that have been receiving increasing attention in recent years due to their diverse biological activities. MELs are produced by certain fungi and display a range of bioactivities, making them attractive candidates for various applications in medicine, agriculture, and biotechnology. Despite their remarkable qualities, industrial-scale production of MELs remains a challenge for fungal strains. Excellent fungal strains and fermentation processes are essential for the efficient production of MELs, so efforts have been made to improve the fermentation yield by screening high-yielding strains, optimizing fermentation conditions, and improving product purification processes. The availability of the genome sequence is pivotal for elucidating the genetic basis of fungal MEL biosynthesis. This review aims to shed light on the applications of MELs and provide insights into the genetic basis for efficient MEL production. Additionally, this review offers new perspectives on optimizing MEL production, contributing to the advancement of sustainable biosurfactant technologies.

Exploring arsenic removal behavior in purification process of antimony metal through vacuum volatilization

This paper proposes a straightforward model that can describe the arsenic(As) impurity behavior during the vacuum volatilization purification process of antimony (Sb) metal. This model aims to determine the optimal degree of volatilization and predict As impurity concentration in the purified Sb metal. Vacuum volatilization experiments were conducted to verify this model at the volatilization temperatures of 700 °C, 730 °C, and 760 °C. The research results indicated that, the concentrations of As impurity in both residue and volatile exhibit an exponentially decreasing trend throughout the entire volatilization process; the decrease in the condensing temperature at the different locations of volatiles leads to an increase in As impurity concentration, which is accompanied by the variations in crystal morphology; there is a good agreement between the calculated and experimental results in the residues, which the mean standard deviations are ± 0.025, ±0.094, and ± 0.148 respectively at the above volatilization temperatures; the calculated results are much higher than the experimental results in the volatiles due to the calculated separation coefficient without the consideration of kinetic factor; the optimal volatilization degrees of 36.50 %, 35.95 %, and 38.44 % respectively result in volatilization removal rates and residual rates both exceeding 60 %; Upon the volatilization degrees are equal to 36.94 %, 30.28 %, and 47.09 %, As impurity decreases from the initial concentrations of 27.82 mg/kg, 22.90 mg/kg, and 35.08 mg/kg to the ultimate concentrations of 10 mg/kg respectively, which meets the purity standard of 4.5 N (99.995 %). Consequently, this model can quantitatively predict As impurity concentration in the purified Sb metal, which provides the theoretical guidance for the As removal from Sb metal by vacuum volatilization.

Sensitive and Low-Noise Perovskite Nanocrystal-Organic Bulk Heterostructure X-ray Detectors Enabled by Sodium Bromide-Assisted In Situ Reparation.

Perovskite nanocrystals (PNCs) offer unique advantages in large-area and thick-film deposition for X-ray detection applications due to the decoupling of the crystallization of perovskite from film formation, as well as their low-temperature and scalable deposition methods. However, the partial detachment of long-chain ligands in PNCs during the purification process would lead to the exposure of surface defects, making it challenging to ensure efficient charge carrier extraction and stable X-ray detection. In this study, we propose a beneficial strategy that involves the in situ reparation of these exposed defects with sodium bromide (NaBr) during the purification process to construct CsPbBr3 PNC-organic bulk heterostructure X-ray detectors. The NaBr-passivated PNCs exhibit stronger photoluminescence intensity and lower trap density in films compared to those of the control samples, confirming the effective passivation of halide vacancy defects. Furthermore, the NiOx hole transport layer with remarkable electron blocking capability is introduced to further suppress the dark current of the devices. Consequently, the optimal devices exhibit a large sensitivity of 4237 μC Gyair-1 cm-2 and a low dark current density of 10 nA cm-2, as well as improved operational stability, which allows for high-contrast and low-dose X-ray imaging applications.

Purification of stilbenes from grape stems in a continuous process based on photo-molecularly imprinted adsorbents and hydroalcoholic solvents

This study presents a sustainable method to purify stilbenes from residual grape stem biomass. This approach was experimentally validated through the use of a pilot size fixed-bed adsorption prototype for the automation of the purification process. Molecularly imprinted polymers, synthesized through photopolymerization at room temperature and incorporating the 4-vinylpyridine monomer, serve as adsorbents. The purification procedure leads to a significant enrichment, with a more than 22-fold increase in (E)-ε-viniferin and a 9-fold increase in (E)-resveratrol. High recoveries of 80.3% and 62.1% for (E)-ε-viniferin and (E)-resveratrol, respectively, were achieved. Notably, the use of eco-friendly water and ethanol mixtures distinguishes this method from others focused on stilbenes purification. This study further explores the variability of the stilbenes in the residual grape stems by analysing different varieties, emphasizing the complexity of the starting material of the purification process. The range of purities achieved for the fractions enriched with stilbenes (e.g., 12.8% for (E)-ε-viniferin and 3.4% for (E)-resveratrol) are suitable for direct use in controlling of Plasmopara viticola, the agent causing grapevine downy mildew. Furthermore, through compositional combination of these fractions, it is possible to conceive new stilbene-containing phytochemicals with improved anti-fungal activity. Therefore, the developed adsorbents and purification process, enabling the steady enrichment of stilbenes regardless of the unavoidable variability in the initial vine biomass, is a contribution towards the quest for more environmentally friendly and sustainable phytochemicals.

Eco-efficient downstream processing of 1,3-propanediol applicable to various fermentation processes

PDO (1,3-propanediol) is a platform chemical that is obtained by petrochemical routes and by fermentation. The latter needs relatively complex downstream processing after fermentation, due to the modest concentration of the high-boiling product, and the presence of microorganisms and many impurities in the fermentation medium. This novel research proposes an original large-scale (production capacity of 23 – 32 ktonne/y) process for the final purification of PDO and dominant by-products, from the fermentation of glucose or glycerol. Following the initial microfiltration, diafiltration, ultrafiltration and ion exchange steps, heat pump-assisted vacuum distillation was implemented to remove most of the water from the broth. Afterwards, an advanced highly-integrated dividing-wall column was designed to allow the final purification of PDO (product purity > 99.9 wt%) from light and heavy by-products. Fermentation by-products that are present in significant amounts can also be recovered and valorized. Overall, the developed final purification processes demonstrate cost-effectiveness (0.150 – 0.274 $/kg) and energy-efficiency (1.258 – 3.175 kWthh/kg) which contributes to the competitiveness of the overall downstream processing (0.256 – 0.384 $/kg and 1.487 – 3.496 kWthh/kg).

Construction of mesoporous PdO/YVO4 p-n heterojunction wrinkled-nanosheets fostering electron transfer for boosted photocatalytic atrazine degradation under visible light

Heterogeneous photocatalysis is an environmentally friendly and sustainable process for water purification. Unluckily, the significant propensity for photo-induced charge carriers to recombine rapidly, as well as poor responsiveness to visible light, are substantial shortcomings in conventional semiconductor photocatalysis. In this study, a facile surfactant-mediated solvothermal process, along with an impregnation approach was applied to fabricate a series of PdO/YVO4 p-n heterostructures with diverse PdO contents for atrazine (AT) oxidation under visible light. Diverse characterization tools confirmed the homogeneous dispersion of PdO nanoparticles (NPs) on mesoporous YVO4 nanosheets, thereby forming p-n junctions and facilitating charge carriers' separation. Moreover, the fabricated p-n heterojunction materials exhibited enhanced photoabsorbance abilities. It was demonstrated that the inclusion of PdO NPs considerably enhanced the photocatalytic capability and performance of the YVO4 candidate under visible light. The complete atrazine decomposition was accomplished on 2.0 g/L of 0.6 wt% PdO/YVO4 with a remarkable rate constant of 52.51 × 10−3 min−1 which was ca. 25.6-folds more than that achieved on bare YVO4 (2.05 × 10−3 min−1), while maintaining a 98.0 % recycling rate. The p-n heterojunction photocatalyst constructed between PdO and YVO4 exhibited a key role in improving the photoharvesting capability and accelerating the separation of photo-produced carriers, generating highly reactive oxygen species to degrade AT effectively. All in all, this achievement proposes a new YVO4-based heterostructures that can effectively eliminate organic contaminants in wastewater and also presents novel ideas for designing other heterojunctions.

Bioinspired axial S-coordinated single-atom cobalt catalyst to efficient activate peroxymonosulfate for selective high-valent Co-Oxo species generation

The efficient activation and selective high-valent metal-oxo (HVMO) species generation remain challenging for peroxymonosulfate (PMS)-based advanced oxidation processes (PMS-AOPs) in water purification. The underlying mechanism of the activation pathway is ambiguous, leading to a massive dilemma in the control and regulation of HVMO species generation. Herein, bioinspired by the bio-oxidase structure of cytochrome P450, the axial coordination strategy was adopted to tailor a single-atom cobalt catalyst (CoN4S-CB) with an axial S coordination. CoN4S-CB high-selectively generated high-valent Co-Oxo species (Co(IV)=O) via PMS activation. Co(IV)=O demonstrated an ingenious oxygen atom transfer (OAT) reaction to achieve the efficient degradation of sulfamethoxazole (SMX), and this allowed robust operation in various complex environments. The axial S coordination modulated the 3d orbital electron distribution of the Co atom. Density functional theory (DFT) calculation revealed that the axial S coordination decreased the energy barrier for PMS desorption and lowered the free energy change (ΔG) for Co(IV)=O generation. CoN4S-PMS* had a narrow d-band close to the Fermi level, which enhanced charge transfer to accelerate the cleavage of O-O and O-H bonds in PMS. This work provides a broader perspective on the activator design with natural enzyme structure-like active sites to efficient activate PMS for selective HVMO species generation.

A novel coal purification-combustion system: Product and efficiency of coal purification process

A novel coal purification-combustion technology is presented to realize the efficient and clean utilization of coal under carbon peaking and carbon neutrality goals. Central to this technology is the implementation of a purification process, the product characteristics, and energy properties of which are the focus of this study. An experimental test of coal purification was conducted using Shenmu coal. The results demonstrate increased coal reactivity following the moderate temperature activation (MTA) process. The high temperature reduction (HTR) phase promotes the production of higher amounts of amorphous carbon, reduces aromatic carbon content, and further decreases fuel particle size. The composite combustion characteristic index(S) of the purified fuel reaches its peak when the excess air coefficient of secondary air (λ2) is 0.36. As λ2 increases from 0.1 to 0.36, the energy in the gas product of the purification system increases from 13700 kJ/kg coal to 25351 kJ/kg coal, while exergy increases from 6530 kJ/kg coal to 11030 kJ/kg coal. The energy efficiency of the purification process ranges from 74.74 % to 80.88 %, with exergy efficiency varying between 60.51 % and 70 %. These findings offer significant insights into refining the coal purification process, ultimately contributing towards maximizing the utility of coal resources.

Development and Validation of an LC-MS/MS Method for the Determination of Plasma and Red Blood Cell Omega Fatty Acids: A Useful Diagnostic Tool

Development and Validation of an LC-MS/MS Method for the Determination of Plasma and Red Blood Cell Omega Fatty Acids: A Useful Diagnostic Tool