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The solubility of limonin in the binary solvent mixtures (methanol + water) and (acetone + water) with various initial mole fractions of methanol or acetone was measured by high-performance liquid chromatography (HPLC) at different temperatures ranging from 283.2 K to 318.2 K. The solubility of limonin increased with increasing initial mole fraction of methanol in (methanol + water) mixtures, whereas it had a maximum point at 0.9 mol fraction of acetone in (acetone + water) mixtures. The solubility of limonin increased with increasing temperature in the two binary solvent mixtures. The solubility of limonin was correlated with temperature by the van’t Hoff model and the modified Apelblat model, and the fitting results showed that the modified Apelblat model had better correlation. The CNIBS/Redlich–Kister model and the simplified CNIBS/Redlich–Kister model were used to correlate the solubility data with the initial solvent composition, the results show that the CNIBS/Redlich–Kister model reveals better agreement with the experimental values. Furthermore, to illustrate the effects of both temperature and initial solvent composition on the changes in the solubility of limonin, the solubility values were fitted by the Jouyban–Acree, van’t Hoff–Jouyban–Acree, modified Apelblat–Jouyban–Acree, Ma and Sun models. Among the five models, the Jouyban–Acree model give the best correlation results for (methanol + water) binary solvent mixtures, while the experimental solubility in the (acetone + water) system was most accurately correlated by the van’t Hoff–Jouyban–Acree model.

In this work, a superparamagnetic Fe 3 O 4 -graphene oxide (MGO) nanocomposite was prepared by one-step chemical co-precipitation method, and characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), powder X-ray diffraction (PXRD), Raman spectroscopy and nitrogen adsorption–desorption curve. The as-prepared MGO was used to adsorb nuciferine, and the adsorption kinetic, isotherm and reusability of MGO were also investigated. The results showed that the adsorption of nuciferine on MGO reached its equilibrium very quickly (within 10 min) due to the two-dimensional carbon nanostructure of GO. In comparison with MGO, five conventional sorbents, i.e., macroporous resin D-101, silica gel, reverse phase silica gel (RP-C18) and cation exchange resin and polyamide, were also used to evaluate their adsorption capabilities. Therefore, MGO combined the advantages of both superparamagnetic particle and GO, i.e., easy separation and high absorption capacity. Finally, MGO was successfully applied to enrichment and separation of nuciferine in the extract of Nelumbinis Folium (Lotus leaf).

In this work, the superparamagnetic Fe 3 O 4 particles prepared by the coprecipitation method were coated successively by SiO 2 , vinyl end groups and molecularly imprinted polymer (MIP) shells to afford a pomegranate-like core/shell superparamagnetic particle (Fe 3 O 4 @SiO 2 @MIP), and the MIP shell preparation conditions were optimized by multi-objective response surface methodology. In order to simultaneously enrich and separate the four taxoids (10-DAB, baccatin III, cephalomannine and paclitaxel), cephalomannine was selected as the template because of its similar chemical structure to other three taxoids and relative inexpensiveness. Especially, to avoid template leaking which may influence the accuracy of identification and quantitation of the analytes, we selected paclitaxel as the target molecular during the investigation of the adsorption property of Fe 3 O 4 @SiO 2 @MIP particles. This strategy was similar to the dummy molecular imprinting technique in which the dummy molecularly imprinted polymer was prepared by using a dummy template, structural analog of the target analyte. The as-prepared Fe 3 O 4 @SiO 2 @MIP particles were characterized by transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and Fourier transform infrared spectroscopy (FTIR). The adsorption kinetics, isotherms and reusability were also investigated. Finally, the Fe 3 O 4 @SiO 2 @MIP particles were successfully applied to simultaneously enrich and separate these four taxoids in the extract of Taxus × media ( T. × media ).

Flexibility was very important for molecularly imprinted membrane (MIM) to apply to practical use. A novel free-standing flexible MIM was prepared using methacrylic acid (MAA) and 2-hydroxyethyl acrylate (HEA) as co-functional monomer, and ionic liquid as porogen. HEA was able to effectively improve the flexibility of MIM. Ionic liquid, 1-butyl-3-methylimidazolium bromide, was able to accelerate the synthesis process and improve the selectivity and adsorption of the MIM. The properties of MIM were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), thermo gravimetric analysis (TGA), differential thermal analysis (DTA) and X-ray photoelectron spectroscopy (XPS). Two structurally similar compounds (octopamine and tyramine) were selected as competitors to examine the selective recognition of MIM to synephrine (SYN). The competitive adsorption and permeation selectivity experiments showed that the MIM could selectively recognize SYN, and was able to be used to selectively separate SYN from the standard mixtures or the extract of stir-baked Aurantii Fructus Immaturus in methanol/water (4:1, v/v) media.

Uniformly sized synephrine molecularly imprinted polymer (MIP) microparticles were prepared via precipitation polymerization. The presence of the template, the amount of monomer, crosslinker, and porogenic solvent could affect the size distribution and morphology of the polymers. The pseudo-second-order kinetic model could provide a better correlation for the adsorption than the pseudo-first-order model. The intraparticle diffusion study showed that the sorption involved intraparticle diffusion, but that was not the only rate-controlling step. The equilibrium data better fit the Freundlich model than the Langmuir model. The Scatchard plot of MIPs revealed MIPs had two groups of sites with different affinities. Subsequent recognition selectivity experiments demonstrated preferential structural selectivity for synephrine with respect to other structurally similar compounds (i.e., octopamine and tyramine). Compared with the bulk MIP of SYN, the SYN MIP microparticles in this work had higher adsorption select...

The solubilities of betulin and betulinic acid were measured at varied values of mole fraction of sodium hydroxide aqueous solutions at a series of temperature (283.2, 293.2, 303.2, 313.2, and 323.2) K. They increase with the increase of temperature. Furthermore, the solubility of betulinic acid has a positive correlation with the mole fraction of sodium hydroxide aqueous solutions, and so is that of the betulin. The experimental solubility resuls are well correlated by the modified Apelblat equation. The enthalpy and entropy of betulin and betulinic acid during the dissolution process in sodium hydroxide aqueous solutions are calculated with the van’t Hoff equation. The results indicate that the dissolution process is endothermal reaction that is driven by entropy.

A novel molecularly imprinted polymer (MIP) using the specific ionic liquid (i.e. 1-vinyl-3-carboxymethylimidazolium bromide, 1-vinyl-3-carboxyethylimidazolium bromide, 1-viny-3-carboxybutylimidazolium bromide, or 1-vinyl-3-carboxypentylimidazolium bromide) as functional monomer was prepared via precipitation polymerization, which can be used to selectively separate synephrine (SYN) from methanol-water media. Ionic liquids are facile to be designed with varying the cation or anion, which enables the specific ionic liquid to be effectively designed to be a functional monomer for the preparation of MIP. The MIP showed a good selectivity and high adsorption capacity for SYN in methanol-water media. The adsorption process could be described by the pseudo-first-order model, which meant that the adsorption kinetics described a diffusion-controlled process. The equilibrium data fitted well to the Freundlich model, indicating multilayer adsorption. Finally, the MIP were successfully applied as sorbent to selectively enrich and separate SYN from the extracts of Aurantii Fructus Immaturus with a relatively high recovery (80-90%).

Surfaces of cationically modified zwitterionic phosphorylcholine (PC) copolymer prepared by spin coating were characterized by spectroscopic ellipsometry (SE), atomic force microscopy, and water contact angle. The obtained PC films bearing cationic charge densities were used to investigate the effect of electrostatic interactions on the adhesion behavior of marine fouling diatom Nitzschia closterium MMDL533. Results show that the settlement of N. closterium MMDL533 cells increases with the positive choline fragment contents in the copolymers. Upon exposure to 8.5-Pa wall shear stress for 2 minutes, the percentage removals of the settled cells on choline containing films were significantly lower than those on the neutral PC1036 films, indicating that the electrostatic attraction between N. closterium MMDL533 cells and the cationic modified PC films could promote the diatom settlement and improve diatom adhesion strength. There were more aggregates adhered on the PC films as compared with the hydroxylated glass slides, which might result from their higher surface hydrophobicity and more heterogeneous surfaces. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

The solubilities of rutaecarpine in 12 organic solvents (dichloromethane, ethyl acetate, acetone, trichloromethane, ethoxyethane, butyl alcohol, isopropyl alcohol, ethyl alcohol, methyl alcohol, cy...

The values of the solubility of evodiamine in chloroform, dichloromethane, acetone, ethyl acetate, 1-butanol, isopropanol, ethanol, methanol, ethyl ether, cyclohexane, n-pentane and n-hexane were measured at T = (283.2, 293.2, 303.2, 313.2, and 323.2) K. The solubility of evodiamine in all the organic solvents studied increases with the increase of the temperature. The experimental solubility values were correlated by a simplified thermodynamic equation and the modified Apelblat equation. The values of the dissolution enthalpy and entropy of evodiamine in all organic solvents were calculated using the van’t Hoff equation. The findings showed that the dissolution process was endothermic and entropy-driven. These data of solubility can be used to guide the processes of extraction, purification in the industry.

Various ionic liquid-based aqueous two-phase systems (IL-ATPS) were evaluated to extract puerarin. The results indicated that the nature of ILs, the salting-out ability of salt, and the acidity and basicity of the salt-rich solution had important influence on the extraction efficiency. Various factors were optimized systematically, that is, the amount of IL, salt, puerarin, and short-chain alcohol. Under the optimal experimental conditions (the amount of K2HPO4 0.30–0.42 g/mL, [Bmim]Br 0.30–0.36 g/mL and 1.0 mL puerarin stock solution), the extraction efficiency of puerarin was over 99% by a single-step extraction, which indicated that the evaluated IL-ATPS was a prospective extraction medium. Finally, the IL-ATPS was successfully used to extract puerarin from Radix Puerariae Lobatae extracts.

The solubility of oleanolic acid and of ursolic acid in (ethanol + water) mixed solvents was measured over the temperature range of (292.2 to 328.2) K. The solubility of oleanolic acid and of ursolic acid in the (ethanol + water) mixed solvent systems increase with increasing the mole fraction of ethanol in mixed solvents. The experimental solubility data are correlated by a simplified thermodynamic equation and the modified Apelblat equation.

An improved high-performance liquid chromatography method for the separation and determination of rotungenic acid and two isomeric triterpene acids (oleanolic acid and ursolic acid) was developed. Results proved that these triterpene acids can be separated with high resolution by adding hydroxypropyl-β-cyclodextrin (HP-β-CD) into the mobile phase; the resolution of the triterpene acids increased and their retention time in the column decreased with HP-β-CD concentrations increasing due to the formation of inclusion complexes between triterpene acids and HP-β-CD. The formation of 1:1 inclusion complexes was assumed and apparent formation constants of triterpene acids with HP-β-CD were determined experimentally at 20°C and 35°C. At last, the method was used to determine rotungenic acid, oleanolic acid, and ursolic acid in the leaves of Diospyros kaki and proved to be sensitive, rapid, accurate, and suitable.

The objective of this work was to examine the feasibility of biogas production from the anaerobic co-digestion of herbal-extraction residues with swine manure. Batch and semi-continuous experiments were carried out under mesophilic anaerobic conditions. Batch experiments revealed that the highest specific biogas yield was 294 mL CH(4) g(-1) volatile solids added, obtained at 50% of herbal-extraction residues and 3.50 g volatile solids g(-1) mixed liquor suspended solids. Specific methane yield from swine manure alone was 207 mL CH(4) g(-1) volatile solid added d(-1) at 3.50 g volatile solids g(-1) mixed liquor suspended solids. Furthermore, specific methane yields were 162, 180 and 220 mL CH(4) g (-1) volatile solids added d(-1) for the reactors co-digesting mixtures with 10%, 25% and 50% herbal-extraction residues, respectively. These results suggested that biogas production could be enhanced efficiently by the anaerobic co-digestion of herbal-extraction residues with swine manure.

Nitrophenols are often found in industrial wastewaters for a wide range of processes; they are highly toxic and potentially carcinogenic. Anaerobic biodegradation of nitrophenols has advantages of relatively low cost, less sludge produced, and high efficiency, when compared with aerobic biodegradation and physical/chemical treatments, although available published results are often contradictory. This paper reports on 2,4-dinitrophenol biodegradation in an anaerobic bioreactor operated in a continuous mode in order to determine optimal operating conditions, and the effects of the main operating parameters such as hydraulic retention time and chemical oxygen demand (COD) loading on the process efficiency. In this study, an 80-day gradual enrichment of an anaerobic culture has been carried out at 25 °C in an anaerobic bioreactor for continuously treating a synthetic wastewater containing 210 mg/l 2,4-dinitrophenol and 100 mg/l nitrate. The results showed that the enriched culture could utilize 2,4-dinitrophenol as a sole electron donor and nitrate as an electron acceptor at the end of the enrichment (on Day 80). Almost all nitrate and 95.5% 2,4-dinitrophenol could be simultaneously removed at a hydraulic retention time of 12 h in the anaerobic bioreactor. The removal of 1 g of the added nitrate required about 4.60 g COD (as provided by the 2,4-dinitrophenol) as the electron donor, and the removal of 2,4-dinitrophenol by this enriched culture was strongly dependent on the presence of nitrate. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.

The effect of high-pressure homogenization (HPH) on the primary extraction of intracellular L-asparaginase from Escherichia coli by aqueous two-phase extraction (ATPE) has been investigated. When HPH was operated under a pressure of 120 MPa for four passages, 17.8% of L-asparaginase activity was lost. The addition of EOPO (a triblock copolymer of a central hydrophobic poly(propylene oxide) (PPO) block with hydrophilic poly(ethylene oxide) (PEO) blocks on each side) could improve the endurance of L-asparaginase to high pressure; while the existence of KHP (a mixture of KH2PO4 and K2HPO4) could strongly facilitate such deactivation. When HPH was operated in the ATPE system formed from EOPO and KHP, the recovery of L-asparaginase was greatly enhanced, as compared to the conventional HPH process. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd.

The aim of this study was to investigate the effects of acrylamide on emulsification of the pseudoternary Span 80-Tween 85/isopar M/water system at 40 °C. It was revealed that acrylamide could act as a surface-active agent to decrease the isopar M/water interfacial tension, and as a hydrotrope to increase the aqueous solubility of Tween 85, and further remarkably influence the emulsification of the investigated pseudoternary Span 80-Tween 85/isopar M/water system. The surface-active role of acrylamide could reduce the minimal weight fraction of the mixture of Span 80 and Tween 85 in pseudoternary systems (XST) to form stable water-in-oil (W/O) emulsions when the weight fraction of acrylamide in the aqueous domain (XAM) is below 0.1; while its hydrotropic role at high XAM levels (>0.1) could drive more Tween 85 molecules to transfer into aqueous phase and slightly improved the minimal XST to form stable W/O emulsions, as compared to that of XAM at 0.1. Moreover, under a given XST, the mean diameter of the droplet size distribution of the W/O emulsion remarkably decreased with the increase in XAM; while the smaller droplets in the W/O emulsion systems at higher level of XAM still coalesced rapidly when the compositions of the emulsion was slightly above the visually determined boundary between non-emulsion and stable emulsion regions.

Phenol and nitrate are two major pollutants simultaneously occurring in several industrial wastewaters. In this study, a 110-day gradual enrichment of an anaerobic culture has been carried out at 25°C in an anaerobic bioreactor for continuously treating a synthetic wastewater containing 600 mg∕L phenol and 430 mg∕L NO3− –N . The results showed that the enriched culture can utilize phenol as a sole electron donor and nitrate as a sole electron acceptor. At the end of the enrichment (on Day 110), 93.3% of phenol and 98.0% of NO3− –N were simultaneously removed at a hydraulic retention time of 20.25 h in the anaerobic bioreactor. The removal of 1 g NO3− –N required about 3.19 g chemical oxygen demand as the electron donor. Batch tests further revealed that cresol, nitrophenol, and monochlorinated phenol (MCP) could exert detrimental influences on the treatment abilities of the enriched culture. However, the inhibitory effects of cresol were impermanent, as compared to those of nitrophenol and MCP. In order t...

Alachlor can be recalcitrant when present at high concentrations in wastewater. Ferrate oxidation was used as a pretreatment to improve its biodegradability and was evaluated by monitoring alachlor elimination and removal of COD Cr (chemical oxygen demand determined by potassium dichromate) during the oxidation process up to a value compatible with biological treatment. Ferrate oxidation resulted in elimination of alachlor followed by degradation of its intermediates. High pH suppressed alachlor removal and COD Cr removal due to the low redox potential of ferrate ions. Although alachlor can be totally eliminated within 10 min under optimized conditions (alachlor, 40 mg l −1 ; ferrate:alachlor molar ratio, 2; and pH 7.0), its complete mineralization cannot be achieved by ferrate oxidation alone. Alachlor solution treated by ferrate for 10 min inhibited an up-flow biotreatment with activated sludge. The biodegradability of ferrate-pretreated solution improved when the treatment was increased to 20 min, at the point of which BOD 5 /COD Cr ratio of the treated solution was increased to 0.87 from 0.35 after 10 min treatment. Under optimized conditions, ferrate oxidation for 20 min resulted in total elimination of alachlor, partial removal of COD Cr and the ferrate-treated solution could be effectively treated by the up-flow activated sludge process.

Multilayer films of amphoteric methylated collagen were assembled on SOURCE 15S or SOURCE 15Q beads by sequential electrostatic deposition with negatively charged methylacrylic acid-hydroxyethyl methacrylate-methyl methacrylate (MAA-HEMA-MMA) terpolymer. Methylated collagen and terpolymer were deposited under conditions where they were oppositely charged to one another, thereby facilitating growth of the films through electrostatic interactions. Measurements revealed alternating positive and negative zeta-potential with the deposition of each methylated collagen and terpolymer layer, respectively. Assembly pH had a remarkable influence on zeta-potential of the assembled multilayers and the deposition of methylated collagen will be frustrated when the assembly pH is up to 9.0. In addition, ionic strength (NaCl concentration) showed an intricate effect on zeta-potential of the films of amphoteric methylated collagen.

Hepatocytes are anchorage-dependent cells sensitive to microenvironment; the control of the physicochemical properties of the extra-cellular matrices may be useful to the maintenance of hepatocyte functions in vitro for various applications. In a microcapsule-based 3-D hepatocyte culture microenvironment, we could control the physical properties of the collagen nano-fibres by fine-tuning the complex-coacervation reaction between methylated collagen and terpolymer of hydroxylethyl methacrylate-methyl methacrylate-methylacrylic acid. The physical properties of the nano-fibres were quantitatively characterized using back-scattering confocal microscopy to help optimize the physical support for hepatocyte functions. We further enhanced the chemical properties of the collagen nano-fibres by incorporating galactose onto collagen, which can specifically interact with the asialoglycoprotein receptor on hepatocytes. By correlating a range of collagen nano-fibres of different physicochemical properties with hepatocyte functions, we have identified a specific combination of methylated and galactosylated collagen nano-fibres optimal for maintaining hepatocyte functions in vitro. A model of how the physical and chemical supports interplay to maintain hepatocyte functions is discussed.

Cephalexin was synthesized in aqueous two-phase systems (ATPSs) by using penicillin G acylase (PGA) (penicillin amidohydrolase, EC3.5.1.11) as a catalyst and 7-aminodeacetoxicephalosporanic acid (7-ADCA) and phenylglycine methyl ester (PGME) as substrates. In the ATPS composed of 20% (w/w) PEG 400 and 15% (w/w) magnesium sulfate, the partition coefficient of PGA (KE) was less than 0.01, PGA biased to the magnesium sulfate-rich bottom phase. The partition coefficient of cephalexin (KC) was 6.7, and the partition coefficients of PGME (KP) and 7-ADCA (KA) were 1.5 and 1.2, respectively. The stability of PGA in 20% (w/w) PEG 400 and 15% (w/w) magnesium sulfate ATPS was investigated. The activity of PGA was remained 80.6% after PGA was retained in the ATPS for 35 h and reserved 59% in the 20% magnesium sulfate solution at pH 7.0. When free enzyme was used for bioconversion, a high yield of cephalexin (60%) was achieved at the concentration of 100 mM 7-ADCA and 100 mM PGME in this ATPS than that of in an aqueous system (21%).

In order to develop an aqueous two-phase system (ATPS) for cephalexin synthesis with extractive bioconversion, the partitioning behaviour of cephalexin and 7-aminodeacetoxicephalosporanic acid (7-ADCA) in poly(ethylene glycol) (PEG)/salt ATPS were examined. Parameters such as PEG size, salt type and tie line length were investigated to find a primary extraction system. In PEG400/ammonium sulfate and PEG400/magnesium sulfate systems, the partition coefficient of cephalexin (KC) was larger than 1 while that of 7-ADCA (KA) deviated about 1.5. Addition of neutral salts, surfactants and water-miscible solvents were also investigated in the primary ATPS in order to improve the separation efficiency. KC greatly increased when neutral salts and surfactants were added to the PEG400/ammonium sulfate primary systems whereas KA was only slightly higher than that of the additive-free ATPS. In an improved ATPS for extractive bioconversion, consisting of PEG400 (20% w/w), ammonium sulfate (17.5% w/w), methanol (5% w/w) and NaCl (3% w/w), a KC value of up to 15.2 was achieved; KA was 1.8; KP (partition coefficient of phenylglycine methyl ester) was 1.2 and the recovery yield of cephalexin was 94.2%. The results obtained from the extractive bioconversion of cephalexin in the improved ATPS showed that it is feasible to perform such an enzymatic process in an ATPS and the system offers the potential as a model for enzymatic synthesis of some water soluble products. © 2001 Society of Chemical Industry

In this work, molecularly imprinted solid-phase extraction (MISPE) has been used to selectively enrich, purify, or remove synephrine from Aurantii Fructus Immaturus. To this end, a molecularly imprinted polymer (MIP) was prepared by self-assembly from the template synephrine, the functional monomer methacrylic acid, and the crosslinker ethylene glycol dimethacrylate in 1:4:20 molar ratio. Subsequent molecular interrogation of the MIP binding sites revealed preferential structural selectivity for synephrine relative to other structurally related naturally occurring compounds (i.e. octopamine and tyramine ). This selectivity was subsequently exploited to achieve substantial sample clean-up of extracts of crude Aurantii Fructus Immaturus and Aurantii Fructus Immaturus stir-baked with bran. The purity of synephrine in the extracts after MISPE represented approximately 24.21-fold enrichment of the synephrine in the untreated extracts of Aurantii Fructus Immaturus stir-baked with bran. High recoveries (85-90%) from the samples proved that the method was valid for selective enrichment, purification, or removal of synephrine from Aurantii Fructus Immaturus.

Ionic liquid (IL) based ultrasonic assisted extraction (ILUAE) was developed for the effective extraction of puerarin from Radix Puerariae Lobatae (RPL). The ILUAE parameters including the type of ILs, IL concentration, RPL amount, ultrasonic power and time were optimized by single-factor experiment and response surface methodology. Under the optimized experimental conditions, the best results were obtained using RPL amount 0.43 g in 10 mL 1.06 mol L −1 1-butyl-3-methylimidazolium bromide aqueous solution, ultrasonic time 27.43 min and ultrasonic power 480 W. Scanning electron microscope images of RPL samples were obtained to provide visual evidence of the sonication effect. Compared with the conventional ultrasonic assisted extraction and refluent extraction, the proposed ILUAE offered shorter extraction time and remarkable higher efficiencies due to the higher penetration ability and solubility of IL and the cavitation phenomenon produced in the solvent by the passage of an ultrasonic wave, which further supported the suitability of the proposed approach.

The feasibility and generic applicability of directly integrating conventional discrete operations of cell disruption by high pressure homogenizer and the product capture by aqueous two-phase extraction (ATPE) system have been demonstrated for the extraction of intracellular L-asparaginase from E. coli. In a side-by-side comparison with the conventional ATPE process, including cell disruption, centrifugal clarification and following ATPE, purification of L-asparaginase via this novel in situ ATPE process yielded a product of L-asparaginase with a higher specific activity of 94.8 U/(mg protein) and a higher yield of 73.3%, both of which in the conventional ATPE process were 78.6 U/(mg protein) and 52.1 %, respectively. In the purification of L-asparaginase (pI=4.9), product-debris interactions commonly diminish its recovery. It was demonstrated that immediate extraction of L-asparaginase in ATPE systems when it is released at pH 5.0 during cell disruption effectively increased its recovery in the top phase due to the reduced interaction between L-asparaginase and cell debris and the reduced degradation by contaminated protease. In addition, no clarification step and/or disruptate storage are required in this in situ ATPE, which reduced the number of unit operations and thus shortened the overall process time. This novel process has a good potential for the separation of other intracellular biological products.

A new class of microcapsules was prepared under physiological conditions by polyelectrolyte complexation between two oppositely-charged, water-soluble polymers. The microcapsules consisted of an inner core of half N-acetylated chitosan and an outer shell of methacrylic acid (MAA) (20.4%)-hydroxyethyl methacrylate (HEMA) (27.4%)-methyl methacrylate (MMA) (52.2%) (MAA-HEMA-MMA) terpolymer. Both 400 and 150 kDa half N-acetylated chitosans maintained good water solubility and supplied enough protonated amino groups to coacervate with terpolymer at pH 7.0-7.4, in contrast to other chitosan-based microcapsules which must be prepared at pH