Tailoring the partitioning of proteins using ionic liquids as adjuvants in polymer-polymer aqueous biphasic systems

Aqueous biphasic systems(ABS)are promising for proteins purification;however,when dealing with samples comprising several proteins,the selectivity towards a target protein is difficult to achieve.In this work,the addition of ionic liquids(ILs)as adjuvants(5 wt%and 10 wt%)in ABS composed of polyethylene glycol(PEG)and dextran was investigated to tailor proteins partitioning between the coexisting phases.The liquid-liquid phase diagrams were determined at 298 K,followed by partition studies of three proteins(bovine serum albumin(BSA),immunoglobulin G(IgG),and cytochrome C(Cyt C)).Partition coefficients of IgG and BSA indicate the preference of both proteins to the dextran-rich phase,whereas Cyt C has no preferential partitioning between the phases.The addition of chloride-based ILs as adjuvants allows to increase or decrease the partition coefficients,thus tailoring the proteins partitioning between the phases.BSA partitioning essentially depends on the IL content in each phase,whereas Cyt C and IgG partitioning is ruled by the ILs chemical structure and established interactions.Molecular docking was carried out to address the ILs effect on the proteins partitioning,supporting experimental observations,while identifying the specific interactions occurring.The partition of each protein in polymer-salt ABS with ILs as adjuvants was determined,demonstrating the higher tailoring ability of polymer-polymer ABS when adding ILs.Finally,the partition of each protein in presence of the remaining ones was determined,as well as the selectivity of the studied systems to separate each pair of proteins,paving the way for their use in liquidliquid chromatography.

Temperature-responsive alkaline aqueous biphasic system for radioactive wastewater treatment

The treatment of anionic ^(99)TcO_(4)^(-)in the waste tank with high alkalinity is still very challenging.In this work,a new temperature-responsive alkaline aqueous biphasic system(ABS)based on(tri-n–butyl)-ntetradecyl phosphonium chloride(P_(44414)Cl)was developed to remove radioactive ^(99)TcO_(4)^(-).The phase transition mechanism was studied by cloud point titration,small-angel X-ray scattering,dynamic light scattering,and molecular dynamic simulations.As the Na OH concentration or temperature increased,the P_(44414)^(+)micelle could grow and aggregate.This micelle showed a particularly high affinity toward ReO_(4)^(-)/^(99)TcO_(4)^(-)compared to other competing anions and could directly extract more than 98.6%of ^(99)TcO_(4)^(-)from simulated radioactive tank waste supernatant.Furthermore,the loaded ^(99)TcO_(4)^(-)could be easily stripped by using concentrated nitric acid rather than metal salt-based reductants.This work clearly demonstrates that the alkaline ABS is a promising separation system for solving the technetium problem in the alkaline waste tank.

A one-pot process based on P_(44414)Cl-HCl aqueous biphasic system for recovering rare earth elements from NdFeB permanent magnet

Recovering critical metals from secondary resources have attracted great interest recently.In this work,a green one-pot leaching-extraction process based on tributyl(tetradecyl)phosphonium chloride (P_(44414)Cl)aqueous biphasic system (ABS) was developed to efficiently recover rare earth elements (REEs) from Nd Fe B permanent magnet.The reaction process,phase separation mechanism,and operation conditions were thoroughly investigated.It is found that the P_(44414)Cl-HCl ABS showed strong extraction ability towards Fe (>99%) whereas only a few REEs (<10%) were extracted,leading to extremely high separation selectivity between Fe and REEs.The characterization results showed that the coordination differences of Fe and Nd in HCl were the main driving forces for such highly selective separation.The phase diagram of P_(44414)Cl-Nd Cl_(3)ABS indicated that the salting-out effect of Nd Cl_(3)was stronger than common chlorides.Due to the hydrophobic property of P_(44414)[Fe Cl_(4)]and salting-out effect of Nd Cl_(3),the P_(44414)Cl could directly form ABS at room temperature after dissolving practical roasted Nd Fe B samples without any other operations and reagents.REEs and Fe could be mutually separated in just one step.Compared with traditional liquid-liquid extraction or ABS separation,this recovery process is green and facile and shows great application prospects in the field of rare-earth recovery.

Aqueous Two-Phase Systems Applied to Partition Proteins from Goat Milk Whey In-Nature

The proteins coming from the milk whey have numerous functional properties. Among the proteins with high bioactivity, α-lactoalbumin (α-La) and β-lactoglobulin (β-Lg) are present in large quantities in the milk whey. In the separation process of proteins, it is important to choose techniques which besides ensuring purity and high yield will not affect the molecule biological activity. The aqueous two-phase systems (ATS) have been utilized with success in the partition of these proteins, however, the studies were performed using protein in its pure form. Studies using milk whey in-nature and goat milk whey have not been found yet. In this context, the objective of this study was to evaluate the liquid liquid equilibrium of aqueous two-phase systems (ATS) in the partition of α-La and β-Lg from goat milk whey in-nature. Equilibrium data were performed considering ATS comprised of polyethylene glycol, potassium phosphate and water at 25°C and pH 7.0. The influence of the polymer molecular weight and amount of goat milk whey in-nature on the partition coefficient of these proteins were assessed. The partition coefficient, selectivity, process yield and purity of α-lactoalbumin and β-lactoglobulin proteins were determined. The results showed that the separation technique by aqueous biphasic systems is applicable indicating high efficiency in the whey proteins separation process.

Rh nanoparticles stabilized by PEG-substituted triphenyl-phosphine:A highly active and recyclable catalyst for aqueous biphasic hydrogenation of benzene

Rh nanoparticles stabilized by PEG-substituted triphenyl-phosphine（PETPP,P[C6H4-p-（OCH2CH2）nOH]3） combining double stabilization effects demonstrated high activity and good recyclability in aqueous biphasic hydrogenation of benzene.The value of turnover frequency（TOF） was 3333 h^-1.Furthermore,the rhodium nanoparticle catalyst could be easily recycled for five times without loss in activity.

Biosynthesis of(R)-2-hydroxy-3-phenylpropionic acid using whole recombinant Escherichia coli cells in an aqueous/n-octane biphasic system

（R）-2-hydroxy-3-phenylpropionic acid （PIP,） is an ideal antimicrobial compound with broad-spectrum activity against a wide range of Gram-positive bacteria, some Gram-negative bacteria, and fungi. We studied the bioconversion of phenylpyruvate （PPA） to PLA using whole recombinant Escherichia coli cells in a series of buffer/organic solvent systems. Octane was found to be the best organic solvent. The optimum volume ratio of the water phase to the n-octane phase, conversion temperature, substrate concentration, and cell concentration were 6：4, 40 ℃, 12.5 g/L, and 30 g/L wet cells, respectively. Under the optimized conditions, the average PLA productivity in the aqueous/ n-octane system was 30.69% higher than that in the aqueous system, and 32.31 g/L PLA was obtained with the use of a stirred reactor （2-L scale）. Taken together, our findings indicated that PLA biosynthesis was more efficient in an aqueous/n-octane biphasic system than in a monophasic aqueous system. The proposed biphasic system is an effective strategy for enhancing PLA yield and the biosynthesis of its analogues.