Forward Extraction Research Articles

Mechanistic deduction of gallium(III) extraction using halogenated secondary amides: Spectroscopic interpretation

Secondary amides act as bifunctional compounds to extract metal anionic species due to the presence of N–H hydrogen and protonated carbonyl oxygen atoms. To exclude the latter function with stronger interaction and less extraction selectivity for metal anionic species, two secondary amide compounds with halogen atoms, namely N-(2-ethylhexyl)-2,2,2-trichloroacetamide as TCAA and N-(2-ethylhexyl)-2,2,2-tribromoacetamide as TBAA, have been synthesised to investigate the efficiency and mechanism of Ga(III) extraction for comparison with N-(2-ethylhexyl)-2,2,2-trifluoroacetamide (TFAA). The 1H NMR spectroscopy results indicated the absence of proton extraction from the carboxylic oxygen atoms of both halogen-containing amides at sufficiently high concentrations of HCl. The three amides exhibited preferential extraction of Ga(III) compared to other metals in highly acidic media. A slope analysis was conducted to assess the stoichiometry for the extraction of Ga(III). The FT-IR and 1H NMR spectroscopies were employed to elucidate the extraction mechanism of GaCl4– using TCAA and TBAA. Therefore, the hydrogen atoms of the N–H group of both amides, with extremely weak δ+ nature, exhibited a distinct extractive preference for anionic GaCl4–. Following the forward extraction, Ga(III) was effectively separated from the organic phase through stripping with distilled water. The extraction efficiencies of GaCl4– among the three amides are not followed by the strength of electron-withdrawing nature of halogen atoms, but the strength of intra- or intermolecular interactions of the amides. This argument was substantiated by calculations using density functional theory (DFT).

Solvent Extraction of Silver(I) using N,N-Diethylacetamido Substituted p-t-Octylcalix[4]arene in Nitrate Media

Solvent extraction of silver ions using tetrakis(N,N-diethylaminocarbonylmethoxy)-p-t-octylcalix[4]arene (EATOC) in chloroform from nitrate medium is presented. The influences on the extraction conditions affecting the behaviour of extraction depending upon the factors such as concentrations of acids, extractants and silver ions as well as extraction time were investigated. Various stripping reagents for back extraction to recover the loaded silver ions by forward extraction process were applied. The extraction mechanism of silver ions using EATOC was established on the 1H NMR chemical shift of the extractant as well as the slope assessments of extraction conditions both before and after loading the silver ions.

Kinetic analysis of an ionic liquid-based metal extraction process using a single droplet extraction column

In this study a liquid-liquid extraction (LLX) process has been investigated based on experimental analysis and kinetic modelling. The purpose of this investigation is (1) to understand the mass transfer behaviour, (2) to determine the rate limiting step via evaluating different mass transfer models, and (3) to estimate the mass transfer and kinetic parameters. This has been discussed in the context of the extraction of Co by the ionic liquid (IL) [P8888][Oleate] as an example of LLX with chemical reaction. Mass transfer models, with and without a chemical reaction, are evaluated based on a statistical cross-validation method. The following operational parameters are included in the analysis: column lengths, droplet diameter, droplet rising velocity and continuous and dispersed phase concentrations on Co uptake. This method reveals that a single parameter representing the external mass transfer resistance can describe the forward extraction of Co (i.e., into the IL) for the whole data set sufficiently accurate (error ±30%) regardless of the studied operational conditions. Back-extraction of Co from pre-loaded IL droplets shows a different transfer mechanism. Now the mass transfer in the dispersed IL phase dominates the process which is attributed to a change of the physical properties of the pre-loaded IL.

Biosurfactant Based Reverse Micellar Extraction of Lactoperoxidase from Whey: Exploitation of Rhamnolipid Characteristics for Back Extraction

ABSTRACT Biosurfactant-based reverse micellar extraction of Lactoperoxidase (LP) was studied using Rhamnolipid (RL) as a biosurfactant. Different solvents were considered to select a suitable organic phase for forming reverse micelles (RM) to varying concentrations of RL for the extraction of LP from its synthetic aqueous solution. The effect of addition of nonionic surfactant as lipophilic linker, whey pH, and ionic strength of the whey was studied to improve the forward extraction of LP from acid whey. About 96.65% LP was extracted to the RM phase during forward extraction. Further, a new back extraction strategy was developed by harnessing the biosurfactant properties. The pH-specific protonation–deprotonation characteristic of the RL headgroups was exploited to overcome the back extraction of LP, which is the rate-limiting step. The back extraction in citrate buffer at pH 5 using 0.75 M KCl resulted in 85.71% active LP recovery with 8.4-fold purification. The effect of the extraction process on the antimicrobial activity of LP was further examined with S. aureus, and the multiplication of the organism was almost arrested even after 24 hr at 9°C.

Kinetics of Extraction of Boric Acid by 2,2,4-Trimethyl-1,3-pentanediol Using Lewis Cell

The extraction kinetics of forward extraction of boron by 2,2,4-trimethyl-1,3-pentanediol (TMPD) were investigated, using a Lewis cell. Factors affecting the extraction rate, including stirring speed, concentrations (TMPD and B(OH)3), interfacial area, and temperature were examined. Results indicated that the extraction rate is controlled by chemical reaction at interface. The activation energy Ea was measured depending on experimental conditions. The extraction rates of B(OH)3 and TMPD are first-order dependent with respect to B(OH)3 and TMPD concentrations, and rate equation is proposed. The rate-determining step is to form the complex at the interface, and the derived extraction mechanism is in good agreement with the experimental results. Based on the above-mentioned regime, an extraction mechanism for boron was also presented.

Allosteric extraction of a second gallium anion assisted by the first, loaded onto a fluorinated secondary amide reagent

• Two secondary amide compounds with and without fluorine atoms were synthesised. • Both extractants exhibited high Ga(III) selectivity in hydrochloric acid media. • The stoichiometries for both extractants to Ga(III) were determined. • The N-H hydrogen atom contributed to Ga(III) extraction at low HCl concentrations. • Allosteric extraction assisted by hydronium was observed for fluorinated reagent. Two secondary amide compounds with and without fluorine atoms, N -(2-ethylhexyl)-2,2,2-trifluoroacetamide (TFAA) and N -(2-ethylhexyl)acetamide (AA), respectively, were synthesised in high yield under different reaction conditions. Both extraction reagents exhibited selectivity for Ga(III) over other metals in competitive solutions from hydrochloric acid media. Comparatively, the extraction selectivity of TFAA was superior to that of AA because of the electron-withdrawing nature of fluorine atoms, which increased the charge density on the N-H hydrogen atom and decreased electron density on the carbonyl oxygen atom of TFAA. The stoichiometries for both extraction reagents to Ga(III) were determined by slope analysis for concentrations of extractants, protons, and chloride ions. FT-IR, 1 H NMR, and 19 F NMR spectroscopic analyses were conducted to elucidate the extraction mechanism. At high HCl concentrations, AA was protonated; consequently, GaCl 4 – was extracted with assistance from the O-bound hydronium ion, while at low HCl concentrations, AA was not protonated and GaCl 4 – and a hydronium ion as a counter cation were extracted via the N-H hydrogen atom. On the contrary, TFAA was not protonated over the entire tested HCl concentration range and extraction of GaCl 4 – occurred only via the N-H hydrogen atom and a hydronium ion as a counter cation. One proton of the hydronium ion bonded to GaCl 4 – and one to an electron-withdrawing fluorine atom; consequently, the remaining hydrogen atom is partially positively charged and extracts a second GaCl 4 – accompanied by a second hydronium ion. Overall, the mechanism involves an allosteric extraction of a second GaCl 4 – assisted by an already TFAA-bound Ga(III) and hydronium ion. Exhaustive stripping of Ga(III) from the organic phase after forward extraction with either amide can be achieved using distilled water.

Effects of AOT reverse micelle extraction on structure and emulsifying properties of soybean protein

AbstractThe present study aimed to investigate the forward and backward extraction efficiency, structure, and emulsifying properties of soybean proteins obtained through bis (2‐ethylhexyl) sulfosuccinate sodium salt (AOT) reverse micelle, as well as their relationship. The results showed that the extraction efficiency was the highest with the forward extraction time of 25 min, pH of 3.0, temperature of 45°C, KCl concentration of 0.0 mol L−1, and the backward extraction time of 10 min, pH of 4.0, temperature of 30°C, KCl concentration of 0.5 mol L−1. Significant changes in the secondary structure and fluorescence intensity of soybean protein after AOT reverse micelle extraction were observed. More β‐sheet structure and higher fluorescence intensity corresponded to the higher emulsion stability of soybean protein. The results indicated that reverse micelle extraction shows great application in food industry.

Improved backward extraction of walnut protein using AOT reverse micelles with microwave and its characteristics

The extraction of walnut protein (WP) was carried out using sodium bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micelles with microwave-assisted backward extraction (MABE), which was potential to improve the extraction yield of WP. And the functional and structural properties were determined. The optimized conditions by response surface methodology were extraction time 30 min, extraction temperature 45°C, and aqueous solution to forward extraction solution ratio 3:1 (vol/vol), the backward extraction yield reached 95.43 ± 2.08%. WP from MABE exhibited the higher solubility (68.35 ± 0.67%), oil absorption capacity (2.43 ± 0.21 g/ml), water holding capacity (2.78 ± 0.02 g/ml), foam capacity (64.03 ± 1.20%), foam stability (72.17 ± 3.05%), emulsifying activity index (3.24 ± 0.86 m2/g), and emulsifying stability index (70.20 ± 0.21 min). FTIR revealed that the main backbone structure changes of WP after microwave treatment did not occur, there was a small change of protein structure, with the increase of α-helix and random coil proportions, decrease of β-turn and similar β-sheet content. Practical applications A novel microwave-assisted backward extraction method of reverse micelle was developed. The backward extraction yield and functionality of walnut protein (WP) with this method could be improved. This work have the potential for promoting the application of reverse micelles in the food industry.

Extraction and reimmobilization of used commercial lipase from industrial waste

In industrial application, immobilized lipase are typically not reused and served as industrial waste after a certain process is completed. The capacity on the reusability of the spent lipase is not well studied. This current study embarks on reusing the remaining lipase from the spent immobilized enzyme. Active lipases were recovered using a simple reverse micellar extraction (RME). RME is the extraction process of targeted biomolecules using an organic solvent and a surfactant. This method was the first attempt reported on the recovery of the lipase from the used immobilized lipase. RME of the spent lipase was done using the nonionic Triton X-100 surfactant and toluene. Various parameters were optimized to maximize the lipase recovery from the used immobilized lipase. The optimum forward extraction condition was 0.075 M KCl, and backward conditions were at 0.15 M Triton X-100/toluene (pH 6, 2 M KCl) with recovery of 66%. The extracted lipase was immobilized via simple adsorption into the ethanol pretreated carrier. The optimum conditions of immobilization resulted in 96% of the extracted lipase was reimmobilized. The reimmobilized lipase was incubated for 20 h in pH 6 buffer at 50 °C of water bath shaker. The reimmobilized lipase still had 27% residual activity after 18 h of incubation, which higher thermal stability compared to the free lipase. In conclusion, the free lipase was successfully extracted from the spent immobilized lipase and reimmobilized into the new support. It exhibited high thermal stability, and the reusability of the spent lipase will promote continued use of industrial lipase and reduce the cost of the manufacturing process.

Relations between b \u2192 c\u03c4\u03bd decay modes in scalar models

As a consequence of the Ward identity for hadronic matrix elements, we find relations between the differential decay rates of semileptonic decay modes with the underlying quark-level transition b → cτν, which are valid in scalar models. The decay-mode dependent scalar form factor is the only necessary theoretical ingredient for the relations. Otherwise, they combine measurable decay rates as a function of the invariant mass-squared of the lepton pair q2 in such a way that a universal decay-mode independent function is found for decays to vector and pseudoscalar mesons, respectively. This can be applied to the decays Bto {D}^{ast}tau v,{B}_sto {D}_s^{ast}tau v,{B}_cto J/psi tau v and B → Dτv, Bs → Dsτv, Bc → ηcτv, with implications for R(D(*)), Rleft({D}_s^{left(ast right)}right) , R(J/ψ), R(ηc), and ℬ(Bc → τv). The slope and curvature of the characteristic q2-dependence is proportional to scalar new physics parameters, facilitating their straight forward extraction, complementary to global fits.

Recovery and purification of Aspergillus niger phytase from crude extract using AOT / isooctane reversed micelles

This work describes the successful extraction of Aspergillus niger phytase from a crude extract (CE) obtained from solid-state fermentation by reversed micelle system using anionic surfactant sodium bis (2-ethylhexyl) sulfosuccinate (AOT) in isooctane achieved in two simple steps: forward and backward extractions. The effects of potassium chloride (KCl) concentration, pH of the aqueous solution, and AOT concentration that affect the system were examined. The best result for the forward extraction was obtained with the CE solution at pH 4.0, 50 mM KCl, and 100 mM AOT, while for the backward extraction the best result was achieved with a stripping aqueous solution at pH 5.5 containing 200 mM KCl, achieving a purification factor of 4.03, 1.15 times higher than that reported for the conventional purification process. Phytase purity was demonstrated by SDS-PAGE (89 kDa) and its activity by zymogram, confirming the efficiency of the process with low time consumption (∼40 min).

Response surface optimization of the forward extraction of jacalin from jackfruit seeds using AOT/isooctane reverse micellar system

Jacalin is the major protein contained in the crude extract of jackfruit (Artocarpus heterophyllus) seed that specifically recognizes and binds reversibly to galactose. Conventionally, purification of jacalin is carried out using the tedious and costly chromatographic techniques. In this study, extraction of jacalin from jackfruit seed crude extract were done using the sodium bis(2-ethylhexyl) sulfosuccinate (AOT)-based reverse micellar system. Reverse micellar extraction is an attractive alternative for downstream processing of various proteins. A successful reverse micellar extraction consists of two basic steps: forward and backward extraction. Forward extraction transfers a target protein from an aqueous solution into the reverse micellar solution, while backward extraction releases the protein from the reverse micelles structure into a new aqueous solution. The effects of the aqueous phase pH, NaCl concentration and AOT concentration on the forward extraction efficiency (FEE) are investigated using the response surface methodology (Box-Behnken Design). The main effects and interactions of the parameters are analyzed through the 3D surface plots. The optimum conditions for forward extraction were determined as follows: aqueous phase pH 4.58, 125 mM NaCl and 40 mM AOT. Under the optimal conditions, the FEE reached 88.04±1.30%, closer to 87.99% predicted by the model. The results indicated that AOT/isooctane reverse micelle system is effective in extracting jacalin from the jackfruit seed crude extract and verified the practicability of the BBD model for optimizing the main parameters in the forward extraction of jacalin.

Forward feature extraction from imbalanced microarray datasets using wrapper based incremental genetic algorithm

Learning from imbalanced datasets is a critical challenge confronting researchers. Unequal distribution of classes in the imbalanced datasets lead to biased classification especially in microarray gene expression analysis. Since all features in the dataset will not contribute to the analysis, only prominent and significant features need to be identified. The paper addresses both these issues by proposing wrapper based incremental genetic algorithm (IGA) which incrementally evaluates and adds attributes into the genetic algorithm process rather than evaluation of all attributes thereby reducing the computational complexity and number of features used and improving the measures like classification accuracy, GMean, F1 measure, precision and recall. The experiments are conducted on 8 microarray gene expression datasets and the results show that performance of IGA is encouraging and superior to existing methods that are compared.

Structural changes of a protein extract from apple with polyphenoloxidase activity obtained by cationic reversed micellar extraction induced by high-pressure carbon dioxide and thermosonication

Polyphenoloxidase from apple was extracted and further concentrated by cationic reversed micellar extraction. Previous to reversed micellar extraction a crude protein extract was obtained using AG2-X8 as adsorbent of phenolic compounds and the detergent Triton X-100. Forward and backward extraction conditions were optimized by using dodecyl trimethyl ammonium bromide as surfactant in the organic phase. Optimization was carried out to obtain the highest value of PPO activity recovery and the purification fold at the different experimental conditions. Under the optimum extraction conditions, PPO activity recovery was 99% and purification fold reached a value of 17, showing that reversed micellar extraction was a good technique as a first step to concentrate on a targeted enzyme. After removing some impurities by centrifuge ultrafiltration, the protein extract with PPO activity was treated by pressurized carbon dioxide and thermosonication achieving residual PPO activity values of 16 ± 3 and 9 ± 1%, respectively. Quenching experiments by iodide performed in the non-treated extract and in the treated extracts revealed conformational changes of this protein fraction reflected in the greater exposure of the fluorophore to the quencher.

Effect of H-bonding effect on reverse micelle extraction of bovine serum albumin

The extraction of bovine serum albumin (BSA) was carried out by using reverse micelles formed by cationic surfactant dodecyltrimethylammonium bromide (DTAB), N-dodecyl-N-2-hydroxyethyl-N,N-dimethyl-ammonium bromide (HDAB) and N-dodecyl-N,N-2-dihydroxyethyl-N-methyl ammonium bromide (DHAB). The factors like pH, surfactant concentration, salt concentration, and co-solvent concentration were investigated. The good maintenance of the secondary structure of BSA after extraction was confirmed by UV spectra. A wider aqueous phase pH range was achieved and less amount of surfactant was needed on efficient forward extraction when hydroxyethyl group was presented in the surfactants’ head group, suggesting an important role of H-bonding effect. At lower pH or high salt concentration, reasonable backward extraction efficiencies were observed in all systems. The little difference of the head group of these surfactants resulted in quite different performance in the extraction process, which provided deeper insight on the effect of fine adjustment of surfactant structure on protein extraction.

Reverse micellar modified mixed anionic and zwitterionic surfactant system for antibiotic extraction

A reverse micellar was modified by combining the anionic AOT and zwitterionic lauryl sulfobetaine surfactant for the extraction of erythromycin was proposed for the first time as a new approach for antibiotic extraction. The stability of the mixed reverse micelle was evaluated in terms of the critical micelle concentration (CMC) using the Wilhelmy Ring method, as well as the thermodynamic properties prior to extraction. The effect of parameters such as AOT concentration, lauryl sulfobetaine fraction and pH of the aqueous phase was investigated during forward extraction. Isopropanol volume percent (%), NaCl concentration, and pH of aqueous phase were investigated during backward extraction. The thermodynamic analysis confirmed the stability of the mixed AOT/lauryl sulfobetaine reverse micelle with a positive synergistic effect. The surface activity was enhanced, by which the CMC of the mixed reverse micelle was significantly lowered, ranging from 0.7 to 5.7 g/L. The overall thermodynamic data comprising ΔGm (between −15.44 and −20.24 kJ/mol), ΔGads (between −27.03 and −28.97 kJ/mol), and ΔGoex (range between −0.39 and 8.87 kJ/mol) are affirmative that micellization was spontaneous. Erythromycin was also found to be interfacially active at all tested condition. The highest erythromycin solubilisation (94.2%) was achieved, even with low AOT surfactant (60.0 g/L) which reflects the synergy between AOT and lauryl sulfobetaine. In addition, in the absence of isopropanol, erythromycin was found to be successfully recovered during the backward extraction. However, isopropanol is still considered as a recovery booster which enables higher erythromycin recovery.

Influence of different parameters on reverse micelle extraction combined with acetone precipitation to purify sn-1,3 extracellular lipase from Aspergillus niger GZUF36

There are few reports on the feasibility of combined reverse micelle extraction and acetone precipitation to obtain electrophoretic pure enzymes. We aimed to purify a sn-1,3 extracellular lipase from a novel Aspergillus niger GZUF36 through this combination in this work. This lipase preliminarily purified by controlling the volume ratio (1:2.5) of crude enzyme solution and acetone. Then, we studied effects of different parameters on reverse micelle extraction. The suitable surfactant, pH, salt and cosolvent and extraction time for forward extraction were 125mM cetyl trimethylammonium bromide (CTAB), 9.0, 0.075M NaCl, 10% n-hexanol and 30min, respectively. Under these conditions, the forward extraction rate reached 90.3% ± 3.2%. The suitable salt, pH, extraction time and short chain alcohol for backward extraction were consecutively 1.5M KCl, 6.5, 60min and 10% ethanol. Adding 10% ethanol shows a significant advantage of improvement the extraction rate. Under these optimal conditions, the total extraction rate and purification factor of lipase reached 76.8% and 10.14, respectively. SDS-PAGE showed that molecular weight of the pure protein was 42.7kDa and TLC exhibited sn-1,3 selectivity of this lipase. LC-MS/MS analysis revealed that the lipase had 297 amino acid residues and was likely to glycosylate. Through the study of different parameters, it demonstrated that the new and simple combination of reverse micelle extraction using CTAB as surfactant and n-hexanol as cosolvent for forward extraction and adding ethanol for backward extraction and acetone precipitation is a promising method to get almost an electrophoretically pure sn-1,3 lipase.

Cationic reverse micellar based purification of recombinant glutaminase free L-asparaginase II of Bacillus subtilis WB800N from fermentation media

Reverse micellar extraction (RME), a liquid-liquid based separation is a versatile tool for protein purification. A statistical approach was employed for the purification of recombinant glutaminase free anti-cancerous enzyme viz., l-asparaginase II to evaluate the effects of RME in current study. The cationic system (CTAB/iso-octane/hexanol/butanol) was used in RME to optimize both forward and backward protein extraction efficiency. By adapting Taguchi's orthogonal array (OA), maximum forward extraction efficiency (FEE) of 86.98% with 84.82% enzyme activity recovery and 1.04 times purification fold achieved with the optimized parameters. Under the optimal levels, the back extraction efficiency (BEE) was observed to be 96.97% with 93.07% enzyme activity recovery and 1.38 times purification fold. Further, mass transfer kinetic studies of RME indicated the mass transfer coefficients of forward and backward extraction to be 0.049 min−1 and 0.036 min−1 respectively.

Fractional Factorial Analysis for Identifying Significant Factors in Extraction of Jacalin From Jackfruit Seeds Using Anionic Reverse Micellar System

Abstract Reverse micellar extraction is emerging as one of the most reliable method for extraction and purification of various proteins and enzymes. In this study, fractional factorial design was used to identify the significant factors having the largest effects on the forward extraction process of jacalin using reverse micelles formed by an anionic surfactant, sodium bis(2-ethylhexyl) sulfosuccinate (AOT). Effect of five different factors, namely the aqueous phase pH, surfactant (AOT) concentration, salt (NaCl) concentration, contact time and volume ratio of organic to aqueous phase on the forward extraction efficiency were investigated using the 25-1 fractional factorial design. The results showed that only the aqueous phase pH, NaCl concentration and concentration of AOT had significant effects on the forward extraction efficiency of jacalin into AOT reverse micelles. Results obtained indicated that the fractional factorial design was a useful method for screening many process factors with minimum number of experiments.

Utilization of green sophorolipids biosurfactant in reverse micelle extraction of antibiotics: Kinetic and mass transfer studies

Reverse micelle extraction of erythromycin and amoxicillin were studied by using eco-friendly sophorolipids biosurfactant. Application of biosurfactant can further improve reverse micelle extraction in terms of sustainability and environmental friendliness compared to synthetic surfactants. The mass transfer behavior of the antibiotics during reverse micelle extraction was investigated. Experimental results show that the reverse micelle extraction of amoxicillin and erythromycin were completed within 200 s. The range of combined mass transfer coefficients obtained is 1.748 × 10−8 to 1.064 × 10−7 for reverse micelle extraction of amoxicillin and 3.395 × 10−7 to 1.131 × 10−6 for erythromycin. The rate limiting steps for each extraction process were identified. The overall mass transfer coefficients of backward extraction were found to be lower than that of forward extraction for both antibiotics which indicates that the forward extraction process was more efficient and faster than the backward extraction. Comparisons between erythromycin and amoxicillin showed that erythromycin has better equilibrium partitioning and larger calculated overall mass transfer coefficients compared to amoxicillin. This may be due to some differences in behaviors and characteristics of amoxicillin and erythromycin during the reverse micelle extraction process. This reverse micelle extraction method was found to be more efficient in extracting erythromycin compared to amoxicillin.