MEASUREMENT AND CORRELATION OF PARTITION COEFFICIENTS OF UROKINASE IN AQUEOUS TWO-PHASE PEG-POTASSIUM PHOSPHATE SYSTEM

Partition coefficients of Urokinase(UK)were measured in aqueous two-phase systems con-taining polyethylene glycol and potassium phosphate at 273.2K.Based on the Diamond-Hsu model,a modified expression was obtained for the correlation of enzyme partitioning in theabove-mentioned systems.Utilizing a modified form,the partitioning data of UK and heteroproteinwere correlated.The results show that the modified model is simple gives good precision.and will fa-cilitate engineering scale-up of aqueous two-phase systems for certain proteins purification.

Extraction of Theanine from Waste Liquid of Tea Polyphenol Production in Aqueous Two-phase Systems with Cationic and Anionic Surfactants

Extraction of theanine from waste liquid of tea polyphenol production was studied in aqueous surfactanttwo-phase system （ASTP） with cationic surfactant （CTAB） and anionic surfactant （SDS）. Results indicate that the region of ASTP is narrow and there is only a two-phase region of cationic surfactant. The increase in concentrations of NaBr and Na2SO4 are beneficial to the formation of ASTP. Theanine concentration in the bottom phase increases with increasing concentration of theanine, whereas the Partition coefficient and extraction rate only change a littlewhen the concentration of theanine is above 0.2 g.L-＇. With the increase of SDS concentration, the phase ratio and the partition coefficient decrease, while the extraction efficiency of theanine increases and the concentration of theanine changes a little in the range from 2.4/7.5 to 2.8/7.2 for SDS/CTAB ratio. The temperature has a notable ef- fect on the concentration of theanine in the bottom phase, partition coefficient and extraction rate of theanine. The increase of waste liquid decreases the phase ratio, increases the concentration and extraction rate of theanine in the bottom ohase, since the orotein and the saccharide enter the bottom nhase with theanine.

Efficient Separation of Butyric Acid by an Aqueous Two-phase System with Calcium Chloride

One of the bottlenecks for bioproduction of butyric acid as bulk chemical is the difficulty in separating butyric acid from the fermentation broth,compared with the petroleum-based chemical synthesis method.In the present work,a novel separation methodology was developed based on an aqueous two-phase system with inor-ganic salts.Calcium chloride was screened out for effective separation of butyric acid from butyric acid-water-salt systems.Within appropriate concentration range of butyric acid and salt,butyric acid was enriched in the upper phase and most of calcium ions remained in the lower phase.This"salting out"effect is very efficient to separate butyric acid from the simulated butyrate fermentation broth,which consists of butyric acid and acetic acid with concentration ratio of 4︰1,so that the final ratio of butyric acid/acetic acid in the upper phase is improved to 9.87. The aqueous two-phase system was used to separate butyric acid from the actual fermentation broth with satisfac-tory result.

Measurement and Correlation of Equilibrium Data for Aqueous Two-phase System Ethanol+Water+ K_2HPO_4

The isothermal solubility data of aqueous two-phase system ethanol+water+K 2HPO 4 were determined with the turbidity titration method at 303.2 K. The binodal curves were described by using the Mistry equation very well. An experimental procedure for measuring the liquid-liquid equilibrium data of the aqueous two-phase system was proposed, in which the concentrations of the coexisting phases were determined with the corresponding densities of the solution. The tie lines were satisfactorily described by using the Othmer-Tobias and Bancroft equations.

Aqueous Two-Phase Interfacial Assembly of COF Membranes for Water Desalination

Aqueous two-phase system features with ultralow interfacial tension and thick interfacial region,affording unique confined space for membrane assembly.Here,for the first time,an aqueous two-phase interfacial assembly method is proposed to fabricate covalent organic framework(COF)membranes.The aqueous solution containing polyethylene glycol and dextran undergoes segregated phase separation into two water-rich phases.By respectively distributing aldehyde and amine monomers into two aqueous phases,a series of COF membranes are fabricated at water-water interface.The resultant membranes exhibit high NaCl rejection of 93.0-93.6% and water permeance reaching 1.7-3.7 L m^(−2) h^(−1) bar^(−1),superior to most water desalination membranes.Interestingly,the interfacial tension is found to have pronounced effect on membrane structures.The appropriate interfacial tension range(0.1-1.0 mN m^(−1))leads to the tight and intact COF membranes.Furthermore,the method is extended to the fabrication of other COF and metal-organic polymer membranes.This work is the first exploitation of fabricating membranes in all-aqueous system,confering a green and generic method for advanced membrane manufacturing.

Effective extraction of elastase from Bacillus sp. fermentation broth using aqueous two-phase system

This paper presents the evaluation of an aqueous two-phase system （ATPS） for extracting elastase produced by Bacillus sp. EL31410. The elastase and cell partition behavior in polyethylene glycol （PEG）/salt systems was investigated. The suitable system for elastase extraction was PEG/KHEPO4-KEHPO4, in which elastase is mainly partitioned into the PEG-rich phase, while the cells remained in the other phase. The influence of defined system parameters （e.g. PEG molecular mass, pH, NaCl addition） on the partitioning behavior of elastase is described. The concentration of phase forming components, PEG and KHEPO4-KEHPO4, was optimized for elastase recovery by means of response surface methodology, and it was found that they greatly influenced extraction recovery. The optimal ATPS was 23.1% （w/w） PEG 2000 and 11.7% （w/w） KHEPO4-KEHPO4. The predicted recovery was about 89.5%, so this process is suggested to be a rapid and convenient method for elastase extraction.

Ionic Liquid-salt Aqueous Two-phase System, a Novel System for theExtraction of Abused Drugs

A 1-butyl-3-methylimidazolium chloride-salt aqueous two-phase system was studied on extraction of abused drugs. The effects of sorts of salts, temperature, concentration of salt and drugs on system were investigated systematically. A satisfactory extraction efficiency of 93% was obtained for papaverine while that of morphine was 65%. The extraction mechanism was primarily discussed.

Simultaneous Cell Disruption and Aqueous Two-Phase Extraction for Isolation of Intracellular Recombinant Proteins

A new technique was developed for the integrated processing of cell disruption and aqueous two-phase extraction in a high-speed bead mill to separate intracellular proteins from microbial cells. The process was named as simultaneous cell disruption and aqueous two-phase extraction (SDATE). Advantages, such as high cell disruption efficiency, biochemical activities preservation of proteins, cell debris elimination, and prelimiary purification of the target protein were being claimed. When this technique was employed for isolating recombinant Tumor Necrosis Factor (TNF) from E. coli, overall protein concentration and TNF activity were found to have been increased. More than 95% of TNF was partitioned into the top phase and all cell debris were in the bottom phase. The partition coefficient was greater than 3 and the TNF purification factor was greater than 6. It is shown that less separation steps were being utilized in the new technique, meaning a reduction in separation time and less process extractors required.

Novel Vesicular Aqueous Two-Phase Systems

The interesting phenopmena of two aqueous phases coexisting in dilute aqueous solutions of sodium undecenoate-dodecyltrimethylammo brodride ndxture and sodium laurate-dodecyltrimethylammonium brondde mixture were investigated. Vesicles existing in both phases were shown by TEM images. The vesicles are dispersed in lower phase and flocculated in upper phase. Multilamellar structure of vesicles was found in the upper phase of sodium laurate-dodecyltrimethylammonium bromide system.

Study on aqueous two-phase systems of the mixture SDS/CTAB surfactants

The phenomenon of two dilute aqueous phases composed of sodium dodecylsulfate(SDS) and cetyl trimethyl ammonium bromide(CTAB) was investigated under various conditions such as concentrations and molar ratios of the two surfactants, the addition of sodium chloride and temperature. Vesicles formation was found in the both phases by TEM image.

Measurement of Mass Transfer Coefficients and Their Modelling of Continuous Counter-Current Aqueous Two-Phase System in a Packed Extraction Column

Overall dispersed side volumetric mass transfer coefficients for protein and amino acids were measured in continuous countercurrent PEG4000/KHP aqueous two-phase systems in a 57mm I.D. packed extraction column. A model for overall dispersed side volumetric mass transfer coefficients was derived by describing the motion of the drops based upon Navier-Stokes equation combined with the relationship between mass transfer coefficients and the drop velocity. The model provides good predictions and can be successfully used in aqueous two-phase extraction. The average relative deviation between calculated values and experimental data ranges from 8% to 14%.

Measurement and Correlation of Partition Coefficients of Baicalin in EOPO/Salt Aqueous Two-Phase Systems

The partition coefficients of baicalin were measured in ethylene oxide and propylene oxide (EOPO)/salt aqueous two-phase systems at 298.15K. It was found that most of baicalin partitioned into EOPO-rich phase. The partition coefficients of baicalin varied from 10 to 120. The effect of various factors, including tie-line length, salt composition, molecular weight of EOPO, and solution pH, on the partition behavior was investigated in EOPO/salt systems. Furthermore the partition coefficients of baicalin were correlated using the modified Diamond-Hsu model. Good agreement with experimental data is obtained. The average relative deviations are less than 5.0%.

Partitioning and purification of extracellular β-1,3-1,4-glucanase in aqueous two-phase systems

The partition behaviors of β-1,3-1,4-glucanase, α-amylase and neutral proteases from clarified and whole fermentation broths of Bacillus subtilis ZJF-1A5 were investigated. An aqueous two-phase system （polyethylene glycol （PEG）/MgSO4） was examined with regard to the effects of PEG molecular weight （MW） and concentration, MgSO4 concentration, pH and NaC1 concentration on enzyme partition and extraction. The MW and concentration of PEG were found to have significant effects on enzyme partition and extraction with low MW PEG showing the greatest benefit in the partition and extraction of β-glucanase with the PEG/MgSO4 system. MgSO4 concentration influenced the partition and extraction of β-glucanase significantly, pH had little effect on β-glucanase or proteases partition but affected a-amylase partition when pH was over 7.0. The addition of NaCl had little effect on the partition behavior of β-glucanase but had very significant effects on the partitioning of α-amylase and on the neutral proteases. The partition behaviors of β-glucanase, α-amylase and proteases in whole broth were also investigated and results were similar to those obtained with clarified fermentation broth. A two-step process for purifying β-glucanase was developed, which achieved β-glucanase recovery of 65.3% and specific activity of 14027 U/mg, 6.6 times improvement over the whole broth.

Highly active and stable Co nanoparticles embedded in nitrogen-doped mesoporous carbon nanofibers for aqueous-phase levulinic acid hydrogenation

Developing a highly active and durable non-noble metal catalyst for aqueous-phase levulinic acid(LA)hydrogenation to g-valerolactone(GVL)is an appealing yet challenging task.Herein,we report well-dispersed Co nanoparticles(NPs)embedded in nitrogen-doped mesoporous carbon nanofibers as an efficient catalyst for aqueous-phase LA hydrogenation to GVL.The Co zeolitic imidazolate framework(ZIF-67)nanocrystals were anchored on the sodium dodecyl sulfate modified wipe fiber(WF-S),yielding one-dimensional(1-D)structured composite(ZIF-67/WF-S).Subsequently,Co NPs were uniformly embedded in nitrogen-doped mesoporous carbon nanofibers(Co^(R)NC/SMCNF)through a pyrolysis-reduction strategy using ZIF-67/WF-S as the precursor.Benefiting from introducing modified wipe fiber WF-S to enhance the dispersion of Co NPs,and Co^(0) with Co-N_xdual active sites,the resulting Co^(R)NC/SMCNF catalyst shows brilliant catalytic activity(206 h^(-1) turnover frequency).Additionally,the strong metal-support interactions greatly inhibited the Co NPs from aggregation and leaching from the mesoporous carbon nanofibers,and thus increasing the reusability of the Co^(R)NC/SMCNF catalyst(reusable nine times without notable activity loss).

Renewable Hydrogen Produced from Different Renewable Feedstock by Aqueous-Phase Reforming Process

Aqueous phase reforming (APR) of biomass derived feedstock producing hydrogen was reviewed. The APR process was discussed based on different feedstock categories such as sugars, polyols and ethanol. The mechanism of APR was analyzed referring to different structures of feedstock. The reaction pathways of APR were investigated. The usage of catalysts should be judged by feedstock on the requirement including C-C bond cleavage, water-gas shift (WGS) reaction, and catalyst maintenance. The prospects were concluded based on the recent works from bimetallic catalysts and high efficient supports. Examples of significant challenges of reducing catalyst cost and increasing catalyst stability have been discussed. The modification and utilization of alkane selectivity of APR processes for liquid fuel production was also investigated.

An Electrochemical Perspective of Aqueous Zinc Metal Anode

Based on the attributes of nonflammability,environmental benignity,and cost-effectiveness of aqueous electrolytes,as well as the favorable compatibility of zinc metal with them,aqueous zinc ions batteries(AZIBs)become the leading energy storage candidate to meet the requirements of safety and low cost.Yet,aqueous electrolytes,acting as a double-edged sword,also play a negative role by directly or indirectly causing various parasitic reactions at the zinc anode side.These reactions include hydrogen evolution reaction,passivation,and dendrites,resulting in poor Coulombic efficiency and short lifespan of AZIBs.A comprehensive review of aqueous electrolytes chemistry,zinc chemistry,mechanism and chemistry of parasitic reactions,and their relationship is lacking.Moreover,the understanding of strategies for suppressing parasitic reactions from an electrochemical perspective is not profound enough.In this review,firstly,the chemistry of electrolytes,zinc anodes,and parasitic reactions and their relationship in AZIBs are deeply disclosed.Subsequently,the strategies for suppressing parasitic reactions from the perspective of enhancing the inherent thermodynamic stability of electrolytes and anodes,and lowering the dynamics of parasitic reactions at Zn/electrolyte interfaces are reviewed.Lastly,the perspectives on the future development direction of aqueous electrolytes,zinc anodes,and Zn/electrolyte interfaces are presented.

Polarizable Additive with Intermediate Chelation Strength for Stable Aqueous Zinc‑Ion Batteries

Aqueous zinc-ion batteries are promising due to inherent safety,low cost,low toxicity,and high volumetric capacity.However,issues of dendrites and side reactions between zinc metal anode and the electrolyte need to be solved for extended storage and cycle life.Here,we proposed that an electrolyte additive with an intermediate chelation strength of zinc ion—strong enough to exclude water molecules from the zinc metal-electrolyte interface and not too strong to cause a significant energy barrier for zinc ion dissociation—can benefit the electrochemical stability by suppressing hydrogen evolution reaction,overpotential growth,and den-drite formation.Penta-sodium diethylene-triaminepentaacetic acid salt was selected for such a purpose.It has a suitable chelating ability in aqueous solutions to adjust solvation sheath and can be readily polarized under electrical loading conditions to further improve the passivation.Zn||Zn symmetric cells can be stably operated over 3500 h at 1 mA cm^(-2).Zn||NH4V4O10 full cells with the additive show great cycling stability with 84.6%capacity retention after 500 cycles at 1 A g^(-1).Since the additive not only reduces H2 evolution and corrosion but also modifies Zn2+diffusion and deposition,highlyreversible Zn electrodes can be achieved as verified by the experimental results.Our work offers a practical approach to the logical design of reliable electrolytes for high-performance aqueous batteries.

Progress on Transition Metal Ions Dissolution Suppression Strategies in Prussian Blue Analogs for Aqueous Sodium-/Potassium-Ion Batteries

Aqueous sodium-ion batteries(ASIBs)and aqueous potassium-ion batteries(APIBs)present significant potential for large-scale energy storage due to their cost-effectiveness,safety,and environmental compatibility.Nonetheless,the intricate energy storage mechanisms in aqueous electrolytes place stringent require-ments on the host materials.Prussian blue analogs(PBAs),with their open three-dimensional framework and facile synthesis,stand out as leading candidates for aqueous energy storage.However,PBAs possess a swift capacity fade and limited cycle longevity,for their structural integrity is compromised by the pronounced dis-solution of transition metal(TM)ions in the aqueous milieu.This manuscript provides an exhaustive review of the recent advancements concerning PBAs in ASIBs and APIBs.The dissolution mechanisms of TM ions in PBAs,informed by their structural attributes and redox processes,are thoroughly examined.Moreover,this study delves into innovative design tactics to alleviate the dissolution issue of TM ions.In conclusion,the paper consolidates various strategies for suppressing the dissolution of TM ions in PBAs and posits avenues for prospective exploration of high-safety aqueous sodium-/potassium-ion batteries.

Trend of Developing Aqueous Liquid and Gel Electrolytes for Sustainable,Safe,and High‑Performance Li‑Ion Batteries

Current lithium-ion batteries(LIBs)rely on organic liquid electrolytes that pose significant risks due to their flammability and toxicity.The potential for environmental pollution and explosions resulting from battery damage or fracture is a critical concern.Water-based(aqueous)electrolytes have been receiving attention as an alternative to organic electrolytes.However,a narrow electrochemicalstability window,water decomposition,and the consequent low battery operating voltage and energy density hinder the practical use of aqueous electrolytes.Therefore,developing novel aqueous electrolytes for sustainable,safe,high-performance LIBs remains challenging.This Review first commences by summarizing the roles and requirements of electrolytes–separators and then delineates the progression of aqueous electrolytes for LIBs,encompassing aqueous liquid and gel electrolyte development trends along with detailed principles of the electrolytes.These aqueous electrolytes are progressed based on strategies using superconcentrated salts,concentrated diluents,polymer additives,polymer networks,and artificial passivation layers,which are used for suppressing water decomposition and widening the electrochemical stability window of water of the electrolytes.In addition,this Review discusses potential strategies for the implementation of aqueous Li-metal batteries with improved electrolyte–electrode interfaces.A comprehensive understanding of each strategy in the aqueous system will assist in the design of an aqueous electrolyte and the development of sustainable and safe high-performance batteries.

EXTRACTION OF INTERFERON-γ USING PEG/K_3PO_4 AQUEOUS TWO-PHASE SYSTEM

The aqueous two-phase system of PEG-4000/K3PO4 is selected to extract interferon-γ（γ-IFN）from the broth of homogenized E.coil cells,which were recombined genetically and werefermented in high expressivity.The effects of pH value and the concentrations of PEG and phos-phate on the partition behavious of γ-IFN and contaminating proteins have been investigated.Theresults show that the pH value is the most influential factor effecting the extraction yield of γ-IFN.Under a suitable condition,an effective separation with high yield of γ-IFN can be achieved.