Top Phase Research Articles

Validation of aqueous two-phase extraction method

Nowadays, consumer interest in food with natural ingredients has increased. This need has led to the research of new sources and green extraction methods. Betalains are compounds responsible for giving color to cacti fruits. The aim is to obtain low-sugar betacyanins extracts from jiotilla Escontria chiotilla using aqueous two-phase systems (ATPS) to color food with the extract. The effect of principal parameters of ATPS (Ethyl alcohol- KH2PO4/K2HPO4) as tie-line length (TL;40,50 and 70), phase volume ratios (Vr; 1 and 3) on the partitioning of betacyanins, betaxanthins, total sugars, reducing sugars, and antioxidant activity in the extract was evaluated. The yields were determined from the top and bottom phases of the aforementioned parameters. Multivariate analysis of variance (MANOVA, α = 0.05) showed that TLL and Vr were statistically significant (P < 0.05). The lowest bottom sugar yield (25.78 ± 3.14%) corresponds to TLL = 40, Vr = 3. Under these conditions, the corresponding value for betacyanins yield is 62.98±4.52%. For the first time, the ATPS was used to extract betacyanins from cactus fruit.•Escontria chiotilla, as a biological source, contained a high percent of betalains•Aqueous two-phase systems (ATPS) was statistically optimized•The developed method enriches the valorization of environmentally related plants waste materials

Deposition of TiO2 thin Films by Dip-Coating Technique from a Two-Phase Solution Method and Application to Photocatalysis

A derivation of the sol-gel-dip-coating deposition technique is proposed, where the precursor solution exhibits two separated liquid phases, reaching an equilibrium state in a heterogeneous solution. Structural, optical and photocatalytic properties of TiO2 films grown from the proposed two phases method are shown and discussed, along with the properties of films deposited when the top phase present distinct lengths, which are observed through SEM images and optical transmittance spectra. The dominant crystalline phase is anatase for all the films prepared. Films are tested towards their efficiency for photocatalysis, using methylene blue as dye degradation agent. It has been found that films deposited through the two phase method are more efficient on the photocatalyitic degradation of methylene blue.

Regime Map and Triple Point in Selective Withdrawal.

Entrainment in selective withdrawal occurs when both the top and bottom phases are withdrawn through a capillary tube oriented perpendicular to a flat gravitationally separated liquid-liquid interface. The tube introduces two distinct features to the conditions for fluid entrainment. First, the ratio of the two phases being withdrawn is affected by the region of influence of the flow upstream of the tube's orifice. Second, a minimum withdrawal flow rate must be reached for entrainment regardless of the distance between the interface and the tube. We show that these phenomena can be understood based on the Reynolds number that governs the external flow field around the capillary tube and the capillary number that regulates the effect of the viscosity and capillarity.

Thermodynamics of acetaminophen and bovine serum albumin partitioning in ternary aqueous solutions comprising polyethylene glycol dimethyl ether 250 and choline bitartrate: Liquid-liquid equilibria, volumetric and acoustic investigations

The present work reports the biocompatible and nontoxic aqueous biphasic system, ABS, for acetaminophen and bovine serum albumin, BSA, separation. First, the binodal curves and tie-lines for {polyethylene glycol dimethyl ether 250 (PEGDME250) + choline bitartrate ([Ch][Bit]) + water} system was measured at different temperatures under atmospheric pressure (≈ 85 kPa). The phase separation in this ABS was studied by the salting-out coefficents obtained from tie-lines correaltion with setschenow equation. The results indicated that the biphasic region was enhanced by enhancing temperatre. The experimental data were fitted by two semi-empirical equations including Marchuk and Zafarani-Moattar equations for binodals and Othmer-Tobias, Bancroft, Osmotic virial equations, and e-or m-NRTL models for the tie-lines. Later, the performance of this ABS in acetaminophen and BSA partitioning was examined via calculation of partition coefficients and extraction efficiencies at different tie-lines and temperatures, the trend showed that the acetaminophen could be partitioned preferentially into the polymer-rich top phase with a single step extraction efficiency up to 80%, in where the BSA was effectively transferred into the [Ch][Bit]-rich bottom phase. In order to evaluate the driving-force for acetaminophen preferentially transferring to top phase, density and sound speed for systems (acetaminophen + PEGDME250 + water) and (acetaminophen + [Ch][Bit] + water) were determined at 298.15 K and the obtained results utilized for calculation the infinite molar volume and compressibility, and the transfer molar volume and compressibility. From density and sound speed results, it may be concluded that the favorable interactions between acetaminophen and PEGDME250 is responsible for preferentially acetaminophen transferring into top phase.

Partitioning behavior of caffeine, lamotrigine, clonazepam and oxcarbazepine in a biodegradable aqueous two-phase system comprising of polyethylene glycol dimethyl ether 250 and choline chloride/saccharose deep eutectic solvent

Aqueous two-phase systems (ATPSs) are well-known as novel, green, non-toxic and sensitive pharmaceutical pretreatment systems, where they are necessary for drug extraction from plasma, serum or urine samples. In the search for new ATPSs, especially those that exemplify the above-mentioned characteristics, here, a systematic investigation of biodegradable ATPS containing polyethylene glycol dimethyl ether 250 and one natural deep eutectic solvent obtained from mixtures of choline chloride as hydrogen bond acceptor (HBA) and saccharose as hydrogen bond donor (HBD) with different molar ratio (i.e. 1:1, 2:1 and 4:1) was made by liquid-liquid equilibria and drug partitioning studies at T = (298.15, 308.15 and 318.15) K under atmospheric pressure (≈85 kPa). The salting-out strength of the natural deep eutectic solvent calculated from fitting solubility data with the effective excluded volume theory was used to explore the influences of temperature and HBA:HBD molar ratio on the phase separation in this ATPS; the trend showed that the biphasic region was expanded by enhancing HBA:HBD molar ratio as well as increasing temperature. The performance of this ATPS for partitioning caffeine, lamotrigine, clonazepam and oxcarbazepine was evaluated by computing their partition coefficients and extraction efficiencies with focusing on the absence or presence of HBD, HBA:HBD molar ratio, temperature, drug nature and mass fractions of natural deep eutectic solvent. In all conditions, the high hydrophobic drugs could be partitioned effectively into the top phase with a single step extraction efficiency up to 90% indicating a preferential interaction between drug and polymer enriched in this phase.

Phase Characterization of Cold Sector Southern Ocean Cloud Tops: Results From SOCRATES

AbstractFor a given cloud, whether the cloud top is predominately made up of ice crystals or supercooled liquid droplets plays a large role in the clouds overall radiative effects. This study uses collocated airborne radar, lidar, and thermodynamic data from 12 high‐altitude flight legs during the Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study (SOCRATES) to characterize Southern Ocean (SO) cold sector cloud top phase (i.e., within 96 m of top) as a function of cloud top temperature (CTT). A training data set was developed to create probabilistic phase classifications based on High Spectral Resolution Lidar data and Cloud Radar data. These classifications were then used to identify dominant cloud top phase. Case studies are presented illustrating examples of supercooled liquid water at cloud top at different CTT ranges over the SO (−3°C &lt; CTTs &lt; −28°C). During SOCRATES, 67.4% of sampled cloud top had CTTs less than 0°C. Of the subfreezing cloud tops sampled, 91.7% had supercooled liquid water present in the top 96 m and 74.9% were classified entirely as liquid‐bearing. Liquid‐bearing cloud tops were found at CTTs as cold as −30°C. Horizontal cloud extent was also determined as a function of median cloud top height.

Elucidating mechanism for the extraction of cobalt, nickel, and iron in polymer-electrolyte aqueous biphasic systems with both phases rich in electrolyte

Polymer-electrolyte aqueous biphasic systems (ABS) have emerged as environmentally and economically sustainable alternatives for the extraction of metals. However, mechanisms of the metal extraction in ABS formed by top and bottom phases enriched in electrolyte need the best elucidation. In this context, extraction of Co(II), Fe(III), and Ni(II) into ABS, which comprised a polymer (PEO1500) or a triblock copolymer (L64 or F68) and a thiocyanate salt, was studied without the use of any auxiliary complexing agent. Metal extraction from the salt-rich phase to the macromolecule-rich phase depended on the hydrophobicity and size of the macromolecule, electrolyte structure, and pH. Extraction around 100% of Fe(III) was achieved in all ABS investigated at pH = 3.0, Co(II) was extracted around 97% in all ABS, while Ni(II) extraction was smaller than 64% for all conditions evaluated. The L64 + NH4SCN + H2O ABS, with a tie-line length of 29% (w/w) afforded a separation factor of 120 for the separation of Co(II) and Ni(II) at pH = 3.0 and 303 for the separation of Ni(II) and Fe(III) at pH = 6.0. It is proposed that the total extraction of Co(II) and Fe(III) ions into the macromolecule-rich phase was mainly determined by the charge transfer between the metal-thiocyanate complexes formed in the ABS and the ethylene oxide units of the macromolecules.

Application of Extractive Fermentation on the Recuperation of Exopolysaccharide from Rhodotorula mucilaginosa UANL-001L

Exopolysaccharides (EPS) are high molecular weight biomaterials of industrial interest due to their variety of applications in the pharmaceutical, cosmetic, environmental, and food industries. EPS produced by Rhodotorula mucilaginosa UANL-001 L has sparked interest due to its bio-adsorbent and wide spectrum antimicrobial properties. However, full exploitation and commercial application of EPS has been restrained due to low yields and high production costs. In the present work, the production and separation of EPS from Rhodotorula mucilaginosa UANL-001L was attempted through extractive fermentation in order to increase EPS production while simplifying the recovery process. Extractive fermentation was implemented with a thermoseparating polymer for phase formation (EOPO 970 and EOPO 12,000); culture viability, biomass generation, EPS production, rheological system properties, and phase formation time and temperature were monitored throughout the process. Extractive fermentation of Rhodotorula mucilaginosa UANL-001L with EOPO 970 resulted in a 42% EPS and 7% biomass recovery on the top phase after 5 to 13-min phase formation time and temperatures between 30 and 40 °C. This is the first report of extractive fermentation application for EPS production by yeast of the genera Rhodotorula, resulting in an interesting strategy for EPS production and recovery, although further optimization is needed.

One-step procedure for peroxidase concentration, dye separation, and color removal by aqueous two-phase system.

The aim of our study is to develop a one-step procedure to remove and degrade dyes from wastewater using a low-cost and efficient system based on aqueous two-phase system (ATPS), a well-known technique used to concentrate and recover enzymes. We investigated the catalytic proprieties of rice bran peroxidase (RBP) and found that this homemade enzyme can remain bound to its substrate for up to 5 days in controlled environments, without denaturing and while maintaining stable oxidation reduction potential (ORP) and pH. This biomolecule showed affinity for the ATPS technique prepared with polyethylene glycol and salt, which improved the relative activity up to 170%. The red dye separation in ATPS top phase was achieved in 3 min, in the RBP presence, with 100% of efficiency, and color removal of 87% was obtained in 24 h of enzymatic reaction. The process has promise to be scaled up to 10-fold and to reuse the reagents from the bottom phase of the ATPS.

Primary capture of Bacillus subtilis xylanase from crude feedstock using alcohol/salt liquid biphasic flotation

Abstract Liquid biphasic flotation (LBF) offers advanced downstream processing of bioproducts by floating of gas bubbles within the biphasic system to enhance the separation efficiency of target bioproducts. In this study, the feasibility of alcohol/salt LBF for primary capture of extracellular Bacillus subtilis xylanase from crude feedstock was investigated. The effects of types of phase-forming components; phase composition; concentration of crude feedstock load; and flotation time on the recovery performance of xylanase in LBF were evaluated. The recovery of xylanase was achieved in LBF comprised of 28 % (w/w) 2-propanol, 22 % (w/w) ammonium sulfate and 10 % (w/w) B. subtilis crude feedstock load. A maximum partition coefficient (Ke) of 13.29 ± 0.14, selectivity (S) of 24.71 ± 0.96 and recovery yield (YT) of 90.03 % ± 0.10 were recorded in the optimum 2-propanol/sulfate LBF with flotation time of 20 min. SDS-PAGE analysis revealed that B. subtilis xylanase was successfully recovered in the 2-propanol-rich top phase with high purity. The findings demonstrated that LBF is a practicable technology for the large-scale production of microbial xylanase in a one-step operation.

Efficiency of polymer/salt aqueous two-phase electrophoresis system for recovery of extracellular Kytococcus sedentarius TWHKC01 keratinase

Keratinase is widely applied in the bioconversion of feather waste to produce value-added bioproducts. The wide applications of industrial keratinase have urged the advancement in producing keratinase with high productivity and yields. The efficiency of aqueous two-phase electrophoresis system (ATPES) to recover extracellular Kytococcus sedentarius TWHKC01 keratinase was investigated. The operation time of 10 min and voltage of 10 V were applied for the recovery of K. sedentarius TWHKC01 keratinase with the PEG 1000/sulfate ATPES. Keratinase was recovered in the PEG-rich phase of the ATPES consists of 23% (w/w) PEG 1000, 18.5% (w/w) ammonium sulfate of pH 9, 20% (w/w) crude feedstock and with 3% (w/w) of NaCl added. Highest partition coefficient (Ke) of 4.63 ± 0.17, recovery yield (YT) of 78.75% ± 0.61, and purification fold (PFT) of 3.89 ± 0.84 were obtained in the optimal ATPES coupled with cathode electrode in top phase and anode electrode in the bottom phase. The introduction of electric field to the ATPS has enhanced the selectivity (S) of the system towards the extracellular keratinase by two-fold from 2.79 ± 0.46 to 5.68 ± 0.43, demonstrating the efficiency of ATPES in separating the keratinase from crude feedstock when compared to conventional two-phase system.

Design and Development of Novel Continuous Flow Stirred Multiphase Reactor: Liquid–Liquid–Liquid Phase Transfer Catalysed Synthesis of Guaiacol Glycidyl Ether

Phase transfer catalysed (PTC) reactions are used in several pharmaceutical and fine chemical industrial processes. We have developed a novel stirred tank reactor (Yadav reactor) to conduct batch and continuous liquid–liquid–liquid (L-L-L) PTC reactions. The reactor had a provision of using three independent stirrers for each phase, thereby having complete control over the rate of mass transfer across the two interfaces. In the continuous mode of operation, the top and bottom phases were continuously fed into the reactor while the middle phase was used as a batch. All three stirrers were used independently, thereby having independent control of mass transfer resistances. The reactor in a batch mode showed higher conversion and selectivity compared to a conventional batch reactor. L-L-L PTC reaction in the continuous mode was successfully performed without loss of the middle catalyst phase and with steady conversion and selectivity. The reaction of guaiacol with epichlorohydrin was conducted as a model reaction, with a 76% conversion of epichlorohydrin, 85% selectivity of guaiacol glycidyl ether, and the middle catalyst phase was stable throughout the process.

Influence of tie line length and volume ratio on the partition behavior of peripheral blood and conjugated CD34 antibody in polymer-polymer aqueous two-phase systems

Aqueous two-phase systems (ATPS) offer great opportunities regarding the purification of stem cells for future medical applications. However, most publications exploring the use of ATPS for the biopurification of stem cells are focused only on the use of a single system or in the comparison of different kinds of systems. These studies do not consider the influence of the parameters of the system on the partition behavior of the biomolecules. Therefore, in the presented work, the influence of the intrinsic parameters tie line length (TLL) and volume ratio (VR) on the partition behavior of human peripheral blood and a fluorescent-labeled CD34 antibody in three different ATPS [PEG (polyethylene glycol) 8000–Dextran 500,000, Ficoll 400,000–Dextran 70,000 and UCON (50-HB-5100)–Dextran 75,000] are investigated. In the PEG-Dextran and UCON-Dextran systems, the blood separation is independent from the two parameters, whereas in the Ficoll-Dextran system, high VR shifts the partition to the top phase. For the conjugated CD34 antibody, higher VR and lower TLL shift the partition behavior to the top phase in all systems. Furthermore, the results propose that VR has a stronger effect on the separation behavior than TLL. These results suggested that both, TLL and VR variations, can be exploited to improve the purification of bioproducts such as stem cells.

Constructing a phase-controllable aqueous biphasic system by using deep eutectic solvent as adjuvant

Aqueous biphasic systems (ABSs) have drawn much attentions in separation fields for their biocompatibility and sustainability. However, it is difficult to control the distribution of analytes in a certain phase, which leads to some problems in achieving selective extraction, recovery and reutilization of extraction agents, and separation of various complex analytes. Herein, we make a breakthrough to realize the precise control of pigments distribution in the PPG400/Na2SO4-based ABSs by an addition of trace deep eutectic solvent (DES). With an increase of DES volume ranging from 0.10 to 0.30 mL, all the amaranth in the top phase gradually shifts to the bottom phase. Amaranth in the upper phase showed a decreased trend from 95.45% to 4.09%. It is found that the addition of DES affects the distribution of phase components in the two phases, resulting in the different polarity of each phase which determines the distribution of pigments. Based on this discovery, we have changed the mass of phase-forming Na2SO4, the opposite transformation of amaranth from the bottom phase to the top phase has also been accomplished. Afterwards, the phase-forming process and the distribution of amaranth has been observed by optical microscope. Finally, the two-phase and three-phase systems have been constructed to separate complex compounds. This study demonstrates the controllable distribution of analytes in the ABSs, opening up a chance to realize selective, recyclable and sustainable separation of essential analytes.

Extraction and purification of gold from raw acidic electronic leachate using an aqueous biphasic system

This work presents a new method for gold extraction and purification from scrap central processing units (CPUs) by using an aqueous biphasic system (ABS) consisting of a biodegradable copolymer and ions already present in the CPU leachate (chloride and nitric acid). In the first step of the gold extraction, 100% of gold is extracted into the macromolecule-rich top phase (TP), without the use of any auxiliary extractants, using the ABS formed from the raw CPU acidic leachate, L64 triblock copolymer, and lithium sulfate. However, gold purity is only 7%(w/w). Therefore, three subsequent steps are necessary to enable gold purification. At the end of the fourth step, 96% of gold is extracted from the raw leachate with 94%(w/w) of purity. Extraction of gold into the TP of the ABS is mainly possible due to the interaction of the negatively charged or neutral gold species, respectively, with pseudopolycation or micelle hydrophobic core present in the TP. Additionally, copper can be recovered during the extraction with purities ranging from 83 to 99%.

A Novel Green Extraction Technique for Extracting Flavonoids from Folium nelumbinis by Changing Osmosis Pressure.

A new green and sustainable extraction technique, namely osmosis extraction (OE), was developed for efficient extracting flavonoids from Folium nelumbinis by changing the osmotic pressure. The antioxidant activities of the extracted flavonoids were also evaluated. Ethanol and ammonium sulfate were selected for the OE system because they are environmentally friendly. The maximum flavonoids concentration in the top phase was obtained with an ethanol volume fraction of 42.0% and the salt mass of 1.9 g. The kinetic behavior of the extraction process showed that OE had higher efficiencies especially coupled with ultrasonication due to the accompanying and serious morphological changes of Folium nelumbinis cells observed by digital microscope and nano-computed tomography (nano-CT). Results of morphological and anatomical features showed that the higher intracellular chemical potential made the cell expand and even led to bursting. The results also showed that the extraction efficiency of flavonoids with high antioxidant activities was higher than that of the traditional method. The interface effect enhanced the extraction during the salting-out extraction and osmosis was the main factor that improved the extraction efficiency.

Rapid identification of capsulated Acinetobacter baumannii using a density-dependent gradient test

BackgroundGram-negative bacterial capsules are associated with production of carbohydrates, frequently resulting in a mucoid phenotype. Infections caused by capsulated or mucoid A. baumannii are associated with increased clinical severity. Therefore, it is clinically and epidemiologically important to identify capsulated A. baumannii. Here, we describe a density-dependent gradient test to distinguish between capsulated and thin/non-capsulated A. baumannii.ResultsThirty-one of 57 A. baumannii isolates displayed a mucoid phenotype. The density-dependent gradient test was comprised of two phases, with silica concentrations of 30% (top phase) and 50% (bottom phase). Twenty-three isolates migrated to the bottom phase, indicating thin or non-capsulated strains, and 34 migrated to the top phase, suggesting strains suspected to be capsulated. There was agreement between the mucoid and the non-mucoid phenotypes and the density-dependent gradient test for all but three isolates. Total carbohydrates extracted from strains suspected to be capsulated were significantly higher. Transmission electron microscopy confirmed the presence of a capsule in the six representative strains suspected to be capsulated.ConclusionsThe density-dependent gradient test can be used to verify capsule presence in mucoid-appearing A. baumannii strains. Identifying capsulated strains can be useful for directing infection control measures to reduce the spread of hypervirulent strains.

Production and partial purification by PEG/citrate ATPS of a β-galactosidase from the new promising isolate Cladosporium tenuissimum URM 7803

β-Galactosidase production, partial purification and characterization by a new fungal were investigated. Partial purification was performed by aqueous two-phase system (ATPS) using polyethylene glycol (PEG) molar mass, PEG concentration, citrate concentration and pH as the independent variables. Purification factor (PF), partition coefficient (K) and yield (Y) were the responses. After identification by rDNA sequencing and classification as Cladosporium tenuissimum URM 7803, this isolate achieved a maximum cell concentration and β-galactosidase activity of 0.48 g/L and 462.1 U/mL, respectively. β-Galactosidase partitioned preferentially for bottom salt-rich phase likely due to hydrophobicity and volume exclusion effect caused in the top phase by the high PEG concentration and molar mass. The highest value of PF (12.94) was obtained using 24% (w/w) PEG 8000 g/mol and 15% (w/w) citrate, while that of Y (79.76%) using 20% (w/w) PEG 400 g/mol and 25% (w/w) citrate, both at pH 6. The enzyme exhibited optimum temperature in crude and ATPS extracts in the ranges 35–50 °C and 40–55 °C, respectively, and optimum pH in the range 3.0–4.5, with a fall of enzyme activity under alkaline conditions. Some metal ions and detergents inhibited, while others stimulated enzyme activity. Finally, C. tenuissimum URM 7803 β-galactosidase showed a profile suitable for prebiotics production.

Experimental investigations of phase change material filled rectangular enclosure with inclined top and side heating mode

Abstract An experimental examinations has been conducted on an inclined top and side heating mode phase change material (PCM) filled rectangular enclosure to understand its applicability in various thermal applications like: photovoltaic (PV) thermal management systems, concentrated PV systems, building thermal management and so on. The basic objective of this research work is to experimentally analyze the melt front propagation and temperature distribution of the PCMs in rectangular enclosure with the top heating mode; which is very rarely available in the literature. Lauric acid and paraffin wax are used during an experimentations as the PCMs. The inclination angles of PCM enclosure are varied with 30°, 60° and 90° with the horizontal. Constant heat flux are applied on the heater surface using halogen lamp assembly. The heat input to the 30° and 60° inclined systems are from top side and for 90° system, the heat input is from the right side. Solid-liquid interface transition of the PCMs and its various heat transfer characteristics are explained in the present research work during the charging period. The result shows that the convection currents inside the PCM container plays the major role on PCMs heat transfer characteristics at different inclination angles. The melting rate of PCMs increases with the increase in the inclination angles; however, the heater plate temperature is observed to be smaller at high inclined systems. Heat transfer from the heater plate to the PCMs are very high during the initial period and it decreases as the time progresses.

Multivariate optimization of an aqueous two-phase extraction for determination of cadmium and manganese in food sample

This study proposes a methodology of determination of cadmium and manganese in food samples using an aqueous two-phase system without extracting agent with F AAS detection. In order to choose the best system for preconcentration, an experimental design with Doehlert matrix was employed, allowing the determination of the system composed by PEO400 + K2HPO4 + H2O with the best extraction efficiency. This same study verified that pH does not influence the extraction percentage. Still in the optimization stage, the best conditions were tie-line length = 53.3%w; mass ratio between bottom and top phases = 0.029; and extraction time = 18hs. The method reached values of LOD (0.45 µg.Kg−1 for Cd(II) and 6.4 µg.Kg−1 for Mn(II)), LOQ (1.5 µg.Kg−1 for Cd(II) and 21 µg.Kg−1 for Mn(II)) and enrichment factor (16 for Cd(II) and 45 for Mn(II)) suitable to determine both analytes in food samples. The intra and inter-day relative standard deviation ranged from 3.28 to 4.37%, and from 5.05 to 6.60% for Cd(II) and Mn(II), respectively. The analysis of the NIST 1575a certified sample had a recovery of 98.2% for cadmium, and NIST 1515 presented recovery of 99.2% for manganese, showing high accuracy. The method was applied to samples of green tea and soluble coffee, and the recovery tests obtained results ranging from 94.0 to 110%. Therefore, the proposed methodology is efficient and without using an extractor, being a highly accurate and environmentally safe alternative for the determination of trace levels of metal in food samples.