Partitioning in Aqueous Two-Phase Systems: Fundamentals,Applications and Trends

Over the last years, aqueous two-phase systems (ATPS) regained an increasing interest due to their potential in the downstream processing of biomolecules. After many years with only a few articles published, a lot of effort and work has been put into studying these systems for the partitioning of a range of compounds including proteins, organic low-molecular weight molecules or metal ions. Although several research and review articles appeared, a background review on ATPS partitioning fundamentals is needed. In this article, partitioning theories and main effects of several important factors for partitioning, such as molecular weight of the polymer, effect of added salts, pH, electrical charges, and temperature on phase diagrams, tie-line lengths, interfacial tension and settling time of the two aqueous phases are extensively reviewed. The trend in ATPS research is given compiling the recent 2008–2013 research articles published in the field.     

多羟基对苯二甲酸类化合物的合成与应用研究进展

多羟基对苯二甲酸类化合物在医药及功能材料上的应用研究得到广泛关注。 选择了其中4个具有重要应用价值的多羟基对苯二甲酸的合成及应用进行了综述。 从中归纳出以苯酚类化合物为起始原料,经Koble-Schmitt法制备,其工艺具有操作简便、生产成本低及环境友好型等特点。     

Partitioning of Some Amino Acids in an Aqueous Surfactant Two-Phase System

Surfactants have found widespread uses in separation science, such as cloud-point extraction and coacervation with certain surfactants, two-phase separation has been studied and practiced for the separation of metal chelators,small organic molecules as well as biomacromolecules.     

Production of Terephthalic Acid from Corn Stover Lignin

Funneling and functionalization of a mixture of lignin‐derived monomers into a single high‐value chemical is fascinating. Reported herein is a three‐step strategy for the production of terephthalic acid (TPA) from lignin‐derived monomer mixtures, in which redundant, non‐uniform substitutes such as methoxy groups are removed and the desired carboxy groups are introduced. This strategy begins with the hydro‐treatment of corn‐stover‐derived lignin oil over a supported molybdenum catalyst to selectively remove methoxy groups. The generated 4‐alkylphenols are converted into 4‐alkylbenzoic acids by carbonylation with carbon monoxide. The Co‐Mn‐Br catalyst then oxidizes various alkyl chains into carboxy groups, transforming the 4‐alkylbenzoic acid mixture into a single product: TPA. For this route, the overall yields of TPA based on lignin content of corn stover could reach 15.5 wt %, and importantly, TPA with greater than 99 % purity was obtained simply by first decanting the reaction mixture and then washing the solid product with water.     

Study on Mass Transfer of Isopropylbenzene and Oxygen in a Two-Phase Partitioning Bioreactor in the Presence of Silicone Oil

A two-phase partitioning bioreactor to treat gas effluents polluted by volatile organic compound has been developed. In this work, both the mass transfer of isopropylbenzene (IPB) and oxygen have been considered in relation to their influence on the hydrodynamics of the reactor and the type of silicone oils used as a second phase. The synergistic effect of silicone oil and stirrer speed on the global oxygen mass transfer coefficient (K _L a) and gas holdup (up to 12%) have been investigated. The addition of 10% of low viscosity silicone oil (10 cSt) in the reactor does not significantly affect the oxygen transfer rate. The very high solubility of IPB in the silicone oil leads to an enhancement of driving force term, especially for high fraction of silicone oil. However, it does not seem useful to exceed a volume fraction of 10% since K _L a _IPB decreases sharply at higher proportions of silicone oil. K _L a _IPB and K _L a _O2 evolve in the same way with the proportion of silicone oil. These results confirm the potentialities of our bioreactor to improve both the oxygen and pollutant gas transfer in the field of the treatment of gaseous pollutants, even for highly concentrated effluents.     

微生物降解对苯二甲酸的培养条件优化

对苯二甲酸降解菌0612进行培养条件优化。结果表明,氮源为尿素,质量浓度为1 400mg/L,对苯二甲酸质量浓度为1 000 mg/L、接种量为4%、温度30～37℃、pH 7、转速为140r/min的时候最适合该菌的生长以及对苯二甲酸的降解。     

高效液相色谱法测定精对苯二甲酸中微量杂质

建立了高效液相色谱法（HPLC）同时测定精对-苯二甲酸（PTA）中微量杂质4-羧基苯甲醛（4-CBA）、对-甲基苯甲酸（P-TOL）和苯甲酸（C7H6O2）含量的方法。采用的色谱柱为Shim-PackWAX-1柱，流动相为0.1mol/L NH3H2PO4 6%CH3OH，(pH4.5)，检测波长为254nm。PTA中微量杂质4-CBA、P-TOL和C7H6O2的含量分别为0.59-235.20mg/kg、4.52-392.00mg/kg和0.28-24.55mg/kg时线性关系良好，其线性相关系数分别为0.9998、0.9997和0.9999。苯甲酸加样平均回收率99.03％，RSD0.37％。     

石墨炉原子吸收光谱法测定精对苯二甲酸产品中7种金属杂质的含量

采用石墨炉原子吸收光谱法测定精对苯二甲酸中钛、钼、铬、镍、钴、锰和铁等7种金属杂质的含量。石墨炉灰化温度为750℃,灰化时间为45min,采用硫酸(1+1)溶液溶解残渣。铁和镍的质量浓度在20μg·L-1以内,钴、锰、铬、钼和钛质量浓度在120μg·L-1以内呈线性。各元素的检出限(3S/N)在0.5~1.6μg·L-1之间,加标回收率在92.0%~105%之间,测定值的相对标准偏差(n=6)小于5%。采用本法测定样品中钴、锰和铁的含量,结果与标准方法所测得结果相吻合。     

植物油酸新戊二醇对苯二甲酸复合酯的合成及性能

用新戊二醇(NPG)和对苯二甲酰氯(TPA)反应生成“低聚物”中间体,当n(NPG)/n(TPA)由2.4增加至3.0时,中间体的聚合度(m)在3.5~1.45之间,收率75.5%。再将中间体与油酸、菜籽油酸进行酯化得到复合酯,收率88.5%。结果表明,复合酯的粘度随着分子量的增大而增大,粘度指数大于125,凝点低于－27℃,氧化稳定性随分子量的增大而提高,生物降解率＞70%,最大无卡咬负荷(PB)为784N,磨斑直径0.41mm,热分解温度＞250 ℃,因此植物油酸新戊二醇对苯二甲酸复合酯是性能良好的绿色润滑剂。     

Reactions of Hydroxyl Radical with Salicylic Acid Derivatives： A Pulse Radiolysis Study

Based on pulse radiolysis of aqueous solutions of two salicylic acid derivatives including ethyl salicylate and benzylsalicylate the transient absorption spectra and the rate constants of hydroxyl radical with salicylic acid derivatives were determined for the first time. The results indicated that ethyl salicylate and benzylsalicylate have efficient activities to scavenge hydroxyl radical.     

生物催化生成对苯二甲酸微生物协同作用的代谢途径分析

建立了对苯二甲酸、对甲基苯甲醛、对甲基苯甲醇、对甲基苯甲酸的高效液相色谱分析方法。采用HypersilSAX阴离子交换柱,流动相为2.5mol/LNH4H2PO4(含10%乙腈),pH4.32,流速0.8mL/min,柱温30℃,紫外检测波长为254nm。在此色谱条件下,各组分在7min内得到很好地分离,回收率符合测定要求。运用本方法测定了睾丸酮丛毛单胞菌和嗜麦芽窄食单胞菌生物催化生成对苯二甲酸不同发酵时间发酵液中主要代谢物含量。同时,采用GC-MS方法检测了有机酸、氨基酸、糖及长链脂肪酸等胞内代谢物,结合HPLC和GC-MS检测结果,分析了嗜麦芽窄食单胞菌和睾丸酮丛毛单胞菌协同作用催化对二甲苯生成对苯二甲酸的代谢途径。     

Experimental and CFD-PBM Study of Oxygen Mass Transfer Coefficient in Different Impeller Configurations and Operational Conditions of a Two-Phase Partitioning Bioreactor

In this work, gas dispersion in a two-phase partitioning bioreactor is analyzed by calculating volumetric oxygen mass transfer coefficient which is modeled using a commercial computational fluid dynamics (CFD), code FLUENT 6.2. Dispersed oxygen bubbles dynamics is based on standard “k-ε” Reynolds-averaged Navier-Stokes (RANS) model. This paper describes a three-dimensional CFD model coupled with population balance equations (PBE) in order to get more confirming results of experimental measurements. Values of k _L a are obtained using dynamic gassing-out method. Using the CFD simulation, the volumetric mass transfer coefficient is calculated based on Higbie’s penetration theory. Characteristics of mass transfer coefficient are investigated for five configurations of impeller and three different aeration flow rates. The pitched six blade type, due to the creation of downward flow direction, leads to higher dissolved oxygen (DO) concentrations, thereby, higher values of k _L a compared with other impeller compositions. The magnitude of dissolved oxygen percentage in the aqueous phase has direct correlation with impeller speed and any increase of the aeration magnitude leads to faster saturation in shorter periods of time. Agitation speeds of 300 to 800 rpm are found to be the most effective rotational speeds for the mass transfer of oxygen in two-phase partitioning bioreactors (TPPB).     

Recovery of Terephthalic Acid from Densified Post-consumer Plastic Mix by HTL Process

In this study, we investigate the hydrothermal liquefaction (HTL) of PET separated from a densified postconsumer plastic mix, with the aim of recovering its monomer. This second raw material is made up of 90% polyolefin, while the remaining 10% is made up of PET, traces of metals, paper, and glass. After preliminary separation by density in water, two batch experiments were performed on the sunken fraction (composed mainly of PET) in a stainless steel autoclave at 345 °C for 30 and 20 min. Both trials resulted in similar yields of the three phases. In particular, the solid yield is around 76% by weight. After a purification step, this phase was analyzed by UV–Vis, ¹H-NMR, and FTIR spectroscopy and resulted to be constituted by terephthalic acid (TPA), a product of considerable industrial interest. The study proved that the hydrothermal liquefaction process coupled with density separation in water is effective for obtaining TPA from a densified postconsumer plastic mix, which can be used for new PET synthesis.     

Partitioning of Recombinant Pseudomonas putida POS-F84 Proline Dehydrogenase in Aqueous Two-Phase Systems: Optimization Using Response Surface Methodology

Applied Biochemistry and Biotechnology - Empirical modeling the partition behavior and recovery of a recombinant Pseudomonas putida POS-F84 proline dehydrogenase (ProDH) in aqueous two-phase...     

Extraction of p-Coumaric Acid and Ferulic Acid Using Surfactant-Based Aqueous Two-Phase System

Ferulic acid (FA) and p-coumaric acid (pCA) are high-value products that can be obtained by alkaline hydrolysis of lignocellulose. Present work explores the potential of surfactant-based cloud-point extraction (CPE) for FA and pCA extraction from corn cob hydrolysate. More than 90 % (w/w) extraction of both FA and pCA was achieved from model system with L92. The partition coefficient of FA and pCA in L92 aqueous phase system was 35 and 55, respectively. A significant enrichment (8–10-fold) of both FA and pCA was achieved in surfactant-rich phase. Furthermore, the downstream process volume was reduced by 10 to 13 times. Optimized conditions (5 %?v/v?L92 and pH 3.0) resulted into 85 and 89 % extraction of FA and p-CA, respectively, from alkaline corn cob hydrolysate. Biocompatibility tests were carried out for L92 for ethanol fermentation and found to be biocompatible. Thus, the new surfactant-based CPE system not only concentrated FA and pCA but also reduced the process volume significantly. Further, aqueous phase containing sugars can be used for ethanol fermentation.     

Partitioning of Porcine Pancreatic Lipase in a Two-Phase Systems of Polyethylene Glycol/Potassium Phosphate Aqueous

The hydrolysis of triglycerides at the oil–water interface, synthesis of esters and transesterification in microaqueous conditions are catalysed by lipase. For its application, a proper purification method was necessary. This study examined the application of an aqueous two-phase system to partition porcine pancreatic lipase. The influence of molecular weight and concentration of polyethylene glycol (PEG), tie line length (TLL), potassium phosphate concentration, sodium chloride (NaCl) addition and temperature in the partition was studied. The enzyme was more efficiently purified in PEG 8,000 at 14.5 °C (PF?=?3.89-fold), presenting more recoveries at the top phase with shorter TLL and lower concentrations of PEG and potassium phosphate. Moreover, the increase of these variables repressed the purification and the further addition of NaCl did not promote the purification of the enzyme. These results demonstrated the efficiency of the aqueous two-phase system on lipase purification.     

高效液相色谱法测定精对苯二甲酸中主要有机杂质

本文建立了期货交割精对苯二甲酸(PTA)样品中主要杂质的快速测定方法,该法对羧基苯甲醛(4-CBA)和对甲基苯甲酸(p-TOL)在0～50.0 mg/kg和0～300.0mg/kg范围内有较好的线性关系,相关系数R=0.9990,平均回收率在89.30%～104.28%,该方法为期货交割PTA样品品质提供了良好的技术支持.     

高效液相色谱用于生物催化法生产对苯二甲酸过程中菌种的筛选

在生物催化法生产对苯二甲酸(PTA)菌种的筛选过程中,建立了高效液相色谱法测定某些假单胞菌的发酵液中对苯二甲酸及中间产物对羧基苯甲醛(4-CBA)、对甲基苯甲酸(p-TOL)的分析方法。优化了色谱条件,在6 min之内完全分离PTA及与其结构类似的4-CBA、p-TOL。本法测定PTA的线性范围为0.2~200μg/mL,线性相关系数为0.9998,相对标准偏差为1.52%。