Polyethylene Glycol Molar Mass Research Articles

Demonstration of Physicochemical and Functional Similarity of Biosimilar Pegfilgrastim-cbqv to Pegfilgrastim.

Pegfilgrastim-cbqv/CHS-1701 (UDENYCA®) (hereafter referred to as pegfilgrastim-cbqv) was approved in 2018 by the US Food and Drug Administration as a biosimilar for pegfilgrastim (Neulasta®) (hereafter referred to as pegfilgrastim). Both pegfilgrastim-cbqv and pegfilgrastim are conjugates of recombinant human granulocyte colony stimulating factor (r-metHuG-CSF) with a 20kDa polyethylene glycol (PEG) indicated to decrease the incidence of infection, as manifested by febrile neutropenia, in patients receiving myelosuppressive anticancer drugs. The demonstration of analytical similarity for PEG-protein conjugates presents unique challenges since both the protein and PEG attributes must be characterized. The current study demonstrates the analytical similarity of pegfilgrastim-cbqv and the reference product, pegfilgrastim. In addition to the physicochemical and functional characterization of the protein, the study assessed attributes specific to PEGylation including PEG size and polydispersity, site of attachment, linker composition, and PEGylation process-related variants. The structural, functional, and stability attributes of pegfilgrastim-cbqv and pegfilgrastim were compared using state-of-the-art analytical methods. For the protein, the primary structure, disulfide structure, and secondary and tertiary structures were assessed using traditional protein characterization techniques such as mass spectrometry (MS), circular dichroism (CD), intrinsic fluorescence, and differential scanning calorimetry (DSC), as well as more advanced techniques such as two-dimensional (2D) nuclear magnetic resonance (NMR) and hydrogen deuterium exchange (HDX). For the PEG moiety, the site of attachment, occupancy, linker composition, size and polydispersity were compared using mass spectrometry (both intact and after endoprotease digestion), multiangle light scattering detection (MALS), and Edman degradation. Purity assessments included the assessment of both protein variants and PEGylation variants using chromatographic and electrophoretic analytical separation techniques. The functional similarity between pegfilgrastim-cbqv and pegfilgrastim was compared using both a cell-based bioassay and surface plasmon resonance (SPR). The degradation rates and stability profiles were compared under accelerated and stressed conditions. Biosimilarity was demonstrated by a thorough assessment of physiochemical and functional attributes, as well as comparative stability, of pegfilgrastim-cbqv relative to pegfilgrastim. These studies demonstrated identical primary structure and disulfide structure, highly similar secondary and tertiary structure, as well as functional similarity. The impurity profile of pegfilgrastim-cbqv was comparable to that of pegfilgrastim with only minor differences in PEGylation variants and a slight offset in the PEG molar mass. These differences were not clinically relevant. The degradation profiles were qualitatively and quantitatively similar under accelerated and stress conditions. The structural, functional, and stability data demonstrate that pegfilgrastim-cbqv is highly similar to the reference product, pegfilgrastim.

Impact of polyethylene glycol molar mass and structural isomer of alcohol on the solubility and dissolution enhancement of mesalazine

This work reports the solubility of mesalazine (5-ASA) in mole fraction terms (x1,T) in mono-solvents of polyethylene glycol (PEG) 400, 1-propanol and 2-propanol along with their binary mixtures in different mass fractions of PEG 400 at 293.15–313.15 K and atmospheric pressure which measured experimentally by a shake-flask technique. The solubility of 5-ASA in these mixtures not only enhances with enhancing temperature, but also raises with raising PEG's mass fraction. Effect of PEG molar mass on the solubility of 5-ASA was also estimated by measuring its solubility in PEG 200 or 600 + 1- or 2-propanol mixtures at 298.15 K. Upon the same temperature and mass fraction of PEGs, the upward trend of 5-ASA mole fractions was: PEG 600 + 1-propanol > PEG 600 + 2-propanol > PEG 400 + 1-propanol > PEG 400 + 2-propanol > PEG 200 + 1-propanol > PEG 200 + 2-propanol indicating, the binary mixtures containing a high molar mass of PEG and 1-propanol with a hydroxyl group attached to carbon number 1 had a more solubilization power. Then, the experimental mole fractions were modelled by some cosolvency and activity coefficient models, and the model parameters were regressed. The back-computed mole fractions of 5-ASA by cosolvency models presented a better agreement with the experimental data than that of activity models and Jouyban-Acree model had the best performance (low overall average percentage deviation of 6.1 %). By means of enthalpy-entropy compensation analysis, non-linear ΔsolH° against ΔsolG° compensation plots with positive and negative slopes were achieved as a consequent of increasing 5-ASA solvation by PEG molecules and the solvent-structure loosing, respectively.

Aqueous two-phase extraction and characterization of thermotolerant alkaliphilic Cladophora hutchinsiae xylanase: biochemical properties and potential applications in fruit juice clarification and fish feed supplementation

Xylanase finds extensive applications in diverse biotechnological fields such as biofuel production, pulp and paper industry, baking and brewing industry, food and feed industry, and deinking of waste paper. Here, polyethylene glycol (PEG)-phosphate aqueous two-phase system (ATPS) was applied for the purification of an alkaline active and thermotolerant xylanase from a marine source, Cladophora hutchinsiae (C. hutchinsiae). In the purification process, the effects of some experimental factors such as PEG concentration and PEG molar mass, potassium phosphate(K2HP04) concentration, and pH on xylanase distribution were systematically investigated. Relative enzymatic activity and purification factor obtained were 93.21% and 7.18, respectively. A single protein band of 28 kDa was observed on SDS-PAGE. The optimum temperature and pH of xylanase with beechwood xylan were 30 °C and 9.0, respectively. The Lineweaver-Burk graph was utilized to determine the K m (4.5 ± 0.8 mg/mL), V max (0.04 ± 0.01 U) and k cat (0.001 s−1) values of the enzyme. It was observed that the purified xylanase maintained 70% of its activity at 4 °C and was found stable at pH 4.0 by retaining almost all of its activity. Enzymatic activity was slightly enhanced with Na+, K+, Ca2+ and acetone. The highest increase in the reducing sugar amount was 53.6 ± 3.8, for orange juice at 50 U/mL enzyme concentration.

Enhancing the equilibrium solubility of salicylic acid in aqueous media by using polyethylene glycols 200, 400 and 600 as cosolvents: Correlation and dissolution thermodynamics

The solubility of salicylic acid in three mixtures of polyethylene glycol (PEG) with different molar masses of 200 to 600 g/mole were experimentally determined by a shake flask method at temperature range of (293.15 to 313.15) K under ambient pressure (≈85 kPa). The experimental results indicated that the solubility of salicylic acid enhanced by the introduction of PEGs to the water, and that could be explained with Hansen’s parameters and like-dissolves-like rule. Based on the results, PEG 600 had the best solubilization power, whereas PEG 200 displayed the lowest solubilization power, and generally the solubility decreased with decreasing molar mass of PEG and also decreasing temperature. Moreover, the equilibrium solid phase crystal of salicylic acid is characterized with X-ray powder diffraction analysis to identify no polymorphic transformation, solvate formation or crystal transition during the whole solvent crystallization process. A number of linear and nonlinear cosolvency models including the Jouyban-Acree based models along with the equations of van’t Hoff, the mixture response surface, the combined nearly ideal binary solvent/Redlich-Kister, λh and the modified Wilson-van’t Hoff were challenged to correlate/predict the solubility of salicylic acid in these mixtures. The computed values of the Jouyban-Acree based models presented a good agreement with the experiment data than the others, as a consequent of a low mean percentage deviation (MPD ≤ 15.7%). According to the enthalpy–entropy compensation analysis, there observed slope changes indicating that two mechanisms, enthalpy or entropy controlled the solubility increment depending on the PEG mass fraction in each solution.

How does Poly(ethylene glycol) with varied chain length affect the thermo-responsive behavior of methyl cellulose in aqueous solutions?

In this study, by using a set of narrowly distributed polyethylene glycol (PEG) samples with varied average molar mass (PEGn, 9 <n < 454), we have systematically studied how PEG molar mass and solution concentration influence the thermal response behavior of methyl cellulose (MC) aqueous solutions (Mw = 4.3 × 105 g/mol, <Rg> = 71 nm) by a combination of isothermal titration calorimetry (ITC), rheometer, UV–vis spectroscopy, laser light scattering (LLS) and atomic force microscopy (AFM). At room temperature, ITC result clarifies the existence of extremely weak hydrophobic interactions between MC and PEG chains. In addition, for MC/PEG mixed solution with shorter PEGs (PEG22 and PEG90), experimentally measured zero-shear viscosity (ηexp) is confirmed to be 5–10% higher than the theoretical values (ηcalc), further supporting the interchain association. Whereas for MC/PEG454, insoluble aggregates are formed, which results in ηexp < ηcalc. Further, dynamic laser scattering (DLS) results further reveal how the percentage of peak area of aggregates depends on the chain length of PEG. During the heating process from T = 20 to 70 °C, a combination of UV, LLS and AFM results clearly illustrates that the shorter PEG chains can effectively stabilize the formed MC fibers and prevent the fiber extension; whereas for longer PEG chains, they can not only promote the nucleation process, but also destabilize the formed fibers and promote the fiber extension. Our result unambiguously reveals the macromolecular effect of PEGs on the thermal response behavior of MC in solutions.

Investigation of the Influence of the Molecular Weight of Polyethyleneglycols on the Optical Properties and Dispersed Characteristics of Sols of Au Nanoparticles used in Medicine

In this work, the synthesis of Au nanoparticles stabilized with polyethyleneglycols with different molecular weights from 200 to 8000 Da was carried out. The synthesis was carried out by the method of chemical reduction in an aqueous medium using sodium citrate as a reducing agent. The dependence of the optical properties on the concentration and molar mass of polyethyleneglycol was studied in the obtained samples of Au nanoparticles. The absorption spectra were recorded using an SF-56 optical spectrometer. The studies were carried out in the visible range of the spectrum from 400 to 800 nm. It was found that the type of spectrum, the position of the surface plasmon resonance band and the optical density of the samples of Au nanoparticles stabilized with PEG-8000 with a concentration of 10 and 20% did not undergo significant changes during storage, which characterizes the high aggregate stability of these sols. The dispersed characteristics of these samples of sols of Au nanoparticles were also studied. The studies were carried out using photon-correlation spectroscopy by the method of dynamic light scattering. It is established that an increase in the concentration of the stabilizer leads to an increase in the average hydrodynamic radius of the particles. This fact is associated with an increase in the thickness of the stabilizer layer and with the "stitching" of the polymer layer of Au nanoparticles with the formation of aggregates. Thus, the best result was found in PEG-8000 samples with concentrations of 10 and 20%, since the type of spectrum, the position of the surface plasmon resonance band and the optical density did not undergo significant changes. Based on the data obtained, it can be concluded that the best stabilizer for Au nanoparticles obtained by the citrate method is PEG-8000 with a concentration of at least 10 %. It is important to note that with an increase in the concentration of the stabilizer, the average hydrodynamic radius of the particles increases. This fact is associated with an increase in the thickness of the stabilizer layer and with the "stitching" of Au nanoparticles.

The influence of reaction conditions on structural properties and swelling kinetics of polyurethane hydrogels intended for agricultural purposes

Polyurethane hydrogels were prepared in open and closed system, in reaction of polyethylene glycol (PEG) with different molar mass (2000, 6000 and 10,000 g/mol) and poly[(phenyl isocyanate)-co-formaldehyde] (PPIF) in order to investigate the influence of different synthesis conditions on the hydrogel structure and consequently swelling properties. The PEG molar mass was varied in order to investigate the correlation between PEG chain length, hydrogel hydrophilicity and absorption capacity. Scanning electron microscopy (SEM) and porosity studies have shown that hydrogels prepared in open system have cellular, sponge-like structure, while preparation in closed system have resulted in hydrogels with compact structure. Morphological differences were reflected on swelling kinetics and compressive properties. Swelling ratio in distilled water increases with increasing in PEG molar mass in both series, but swelling behavior of hydrogels synthesized in open system follows second-order kinetics and in closed system first-order kinetics, slower response in first 180 min, but greater capacity to retain water. Compressive modulus increases with increasing in PEG molar mass and has greater values for hydrogels synthesized in closed system. Granulated PU-PEG hydrogels have demonstrated ability to retain and deliver water in soil and contribute to tomatoes growth. Addition of hydrogel in 1 wt% in soil has resulted in higher and more developed plant. Applying the procedure of preparation in open and closed system using the same compounds give hydrogels with a different morphology, swelling and mechanical properties, which implies different application. However, comminution of both type of hydrogels to the level under the pore size, when the morphological differences disappears, give the granules (diameter around 2 mm) with the same swelling properties and potential application in agriculture.

Interphase Control for Electrodeposition of Thin Lithium Films for Lithium Metal Batteries

Rechargeable lithium metal batteries including Li-S batteries, need a thin lithium anode with high purity for high energy density and long cycle life. Today, lithium metal is typically produced from Li2CO3. In contrast to the price of Li2CO3, which is often used for benchmarking, pure lithium metal is actually a costly component. In addition, it has quite some CO2 footprint as it needs significant amounts of energy to produce. Lithium foils of few hundred micron thick are produced by lithium extrusion and cold rolling. To limit cost and to increase energy density, maximum only a few tens of microns is. However, due to the soft nature of lithium, foils of few tens of micrometers are very difficult to manufacture at large volumes and too expensive for cost competitive high energy density Li-metal based cells. Hence, the production of thin lithium foils is currently a bottleneck.The electrodeposition of thin lithium films directly on copper current collector foils could be a cost effective and elegant method, where it not for the high reactivity of lithium with the electrolyte solution and the poor control of lithium morphology. Recently, several approaches have been pursued on lithium electrodeposition by stabilizing the lithium metal-electrolyte interface with the use of solid electrolytes and polymer coatings on electrode [1], however a poor quality of solid electrolyte interphase (SEI) and lithium metal deposition remain as a challenge.Among the various solid-state electrolytes, nitrogen doped lithium phosphate glass or LiPON has been evaluated as solid-electrolyte coatings on electrode particles as buffer layer between active material and the bulk electrolyte [2]. Previously, we investigated the stability of 100 nm down to 10 nm LiPON thin-films as artificial solid-electrolyte interphase for lithium plating and stripping on copper current collectors. We demonstrated the reversible plating/stripping of 150 nm lithium layer for over 100 cycles, indicating formation of a uniform lithium metal layer in-between substrate and LiPON layer [3].In the present work, we further investigated the effect of artificial solid electrolyte interphase, such as LiPON and poly(ethylene) glycol (PEG) coatings, on the deposition behavior of lithium to fabricate micro-meter thick lithium layer which is desirable for negative electrode in next-generation battery application. With a thin LiPON (<150 nm) layer, lithium layer uniformly grew up to 1 μm between substrate and LiPON without breaking of LiPON layer. However, the breakage of the thin LiPON layer was observed with further growth of lithium layer leading to dendrite growth. On the other hand, with a thick PEG coating (> 1 μm) dendrite growth was mitigated by increasing the molar mass of PEG from 8000 to 600,000 g/mol. Furthermore, addition of PEG into the carbonate-based electrolyte resulted in a denser lithium film with a thickness of 2-5 μm without dendrites. In the presentation, effect of molar mass, concentration of PEG on growth behavior of lithium will be further discussed.

PEG size effect and its interaction with Fe3O4 nanoparticles synthesized by solvothermal method: morphology and effect of pH on the stability

The synthesis and characterization of Fe3O4 magnetic nanoparticles (MNPs) obtained by the solvothermal method in ethyleneglycol with the addition of polyethyleneglycol (PEG) with molar mass of 4000, 8000 and 20000 g mol−1 are described, aimed at evaluating its effect on the size, morphology and stability of the nanoparticle. The syntheses were carried out by solubilizing the precursors at 85 and 140 °C, providing smaller nanoparticles as well as smaller crystallites at higher temperatures, while the effect of PEG was less evident. Measurements of nanoparticle surface areas synthesized with PEG 4000 and 20000 g mol−1 at 140 °C provided values of 76 and 14 m2 g−1, respectively, indicating that PEG 4000 surrounds the crystallites, while PEG 20000 preferably surrounds the whole MNP. As a consequence, MNP with very dissimilar porosities were obtained. Electron energy loss spectroscopy (EELS) indicated that MNP synthesized with PEG 20000 possesses higher electronic density than those obtained with PEG 4000, in agreement with the surface area results. Infrared spectroscopy and thermogravimetric analysis demonstrated the presence of PEG in the particles, whose amount increased as the particle size decreased. Dynamic Light Scattering (DLS) measurements showed that MNP hydrodynamic radius increases with the PEG size and stability in solution increases from pH 5.0 to 9.0 for smaller NP, while polymer presents slight effect on stability for the larger particles. The results obtained in this work show that properties of MNP can be tuned by the dissolution temperature of the chemical precursors and the PEG molar mass, changing their porosity and stability in solution, that are important variables in processes of adsorption, drug delivery and sensor developing.

Purification and characterization of fibrinolytic protease from Streptomyces parvulus by polyethylene glycol-phosphate aqueous two-phase system.

Fibrinolytic proteases are a promising alternative in the pharmaceutical industry, they are used in the treatment of cardiovascular diseases, especially thrombosis. Microorganisms are the most interesting source of fibrinolytic proteases. The aim of this study was the production of fibrinolytic protease from Streptomyces parvulus DPUA 1573, the recovery of the protease by aqueous two-phase system and partial biochemical characterization of the enzyme. The aqueous two-phase system was performed according to a 24-full factorial design using polyethylene glycol molar mass, polyethylene glycol concentration, citrate concentration and pH as independent variables. It was analyzed the effect of different ions, surfactants, inhibitors, pH and temperature on enzyme activity. The best conditions for purifying the enzyme were 17.5% polyethylene glycol 8,000, 15% Phosphate and pH 8.0, it was obtained a partition coefficient of 7.33, a yield of 57.49% and a purification factor of 2.10-fold. There was an increase in enzyme activity in the presence of Fe2+ and a decrease in the presence of $\beta$-Mercaptoethanol, phenylmethylsulfonyl fluoride and Iodoacetic acid. The optimum pH was 7.0 and the optimum temperature was 40 ºC. The purified protease exhibited a molecular mass of 41 kDa. The fibrinolytic protease from Streptomyces parvulus proved to be a viable option for the development of a possible drug with fibrinolytic action.

Production and partial purification by PEG/citrate ATPS of a β-galactosidase from the new promising isolate Cladosporium tenuissimum URM 7803

β-Galactosidase production, partial purification and characterization by a new fungal were investigated. Partial purification was performed by aqueous two-phase system (ATPS) using polyethylene glycol (PEG) molar mass, PEG concentration, citrate concentration and pH as the independent variables. Purification factor (PF), partition coefficient (K) and yield (Y) were the responses. After identification by rDNA sequencing and classification as Cladosporium tenuissimum URM 7803, this isolate achieved a maximum cell concentration and β-galactosidase activity of 0.48 g/L and 462.1 U/mL, respectively. β-Galactosidase partitioned preferentially for bottom salt-rich phase likely due to hydrophobicity and volume exclusion effect caused in the top phase by the high PEG concentration and molar mass. The highest value of PF (12.94) was obtained using 24% (w/w) PEG 8000 g/mol and 15% (w/w) citrate, while that of Y (79.76%) using 20% (w/w) PEG 400 g/mol and 25% (w/w) citrate, both at pH 6. The enzyme exhibited optimum temperature in crude and ATPS extracts in the ranges 35–50 °C and 40–55 °C, respectively, and optimum pH in the range 3.0–4.5, with a fall of enzyme activity under alkaline conditions. Some metal ions and detergents inhibited, while others stimulated enzyme activity. Finally, C. tenuissimum URM 7803 β-galactosidase showed a profile suitable for prebiotics production.

Solid-liquid equilibria and thermodynamic correlation for the ternary system (KCl + PEG10000/20000 + H2O) at 288.2 K and 298.2 K

This work finished measuring the phase equilibria of ternary systems {KCl + polyethylene glycol (PEG) 10000/20000 + H2O} at 288.2 and 298.2 K. The solubility, density and refractive index were determined and corresponding diagrams were plotted in this work. There was only solid–liquid phase equilibrium existing in the ternary systems {KCl + PEG10000/20000 + H2O} at 288.2 K and 298.2 K. All of the phase diagrams of four systems are divided into three parts which respectively are the regions of unsaturated homogeneous liquid (L), one liquid and one solid KCl (L + S), and one liquid and two solids KCl and PEG (L + 2S). In addition, the effects of molar mass of PEG (PEG1000/4000/10000/20000) and temperature (288.2 K and 298.2 K) on phase equilibria were discussed. Results show that the sizes of regions of (L) and (L + S) increased and that of (L + 2S) decreased with the increase of temperature, and the regions of (L) and (L + S) decreased and that of (L + 2S) increased with the increase of the molar mass of PEG. The modified Pitzer model was adopted as the equilibrium thermodynamics model to correlate the experimental data. Comparing the experimental data and calculated dada, it can give a precise result with small error.

Partial purification of fibrinolytic and fibrinogenolytic protease from Gliricidia sepium seeds by aqueous two-phase system

Abstract Fibrinolytic proteases are enzymes that provide a promising alternative to drugs for thrombolytic therapy, since they degrade fibrin, the major component of blood clots. Aqueous two-phase systems (ATPS) using polyethylene glycol (PEG) 8000 and sodium phosphate were used to select optimal conditions for extracting a cysteine protease with fibrinolytic and fibrinogenolytic activity from the legume Gliricidia sepium PBSGS. For this purpose, extraction tests were conducted in accordance with a 24-factorial design, in which concentrations of PEG (CPEG), molar mass of PEG, concentrations of sodium phosphate (CPHO) and pH were used as independent variables, and partition coefficient, activity yield and purification factor as responses. The best results in terms of enzyme partial purification were obtained at CPEG of 12.5% (w/w), CPHO of 15% (w/w) and pH 8.0, which guaranteed a purification factor of 6.26, a partition coefficient of 1.32 and a yield of 141.57%. The results clearly showed preferential protease partitioning to the PEG-rich top phase. The enzyme, which was able to degrade human fibrinogen, was characterized as a cysteine protease (66 kDa) and exhibited optimum activity temperature of 60 °C and pH of 8.0; in addition, its activity was increased in the presence of potassium, iron, zinc and sodium ions and reduced in the presence of calcium ion. The results obtained suggest potential of ATPS-partially purified protease in thrombolytic treatment, which will be the object of future investigation.

Purification of Pseudomonas sp. proteases through aqueous biphasic systems as an alternative source to obtain bioactive protein hydrolysates.

Aqueous biphasic systems (ABSs) are an interesting alternative for separating industrial enzymes due to easy scale-up and low operational cost. The proteases of Pseudomonas sp. M211 were purified through ABS platforms formed by polyethylene glycol (PEG) and citrate buffer salt. Two experimental designs 23 + 4 were performed to evaluate the following parameters: molar mass of PEG (MPEG ), concentration of PEG (CPEG ), concentration of citrate buffer (CCit ), and pH. The partition coefficient (K), activity yield (Y), and purification factor (PF) were the responses analyzed. The best purification performance was obtained with the system composed of MPEG =10,000 g/mol, CPEG =22 wt%, CCit =12 wt%, pH=8.0; the responses obtained were K=4.9, Y=84.5%, PF=15.1, and tie-line length=52.74%. The purified proteases of Pseudomonas sp. (PPP) were used to obtain hydrolysates of Lupinus mutabilis (Peruvian lupin cultivar) seed protein in comparison with the commercial protease Alcalase® 2.4L. A strong correlation between hydrolysis degree and radical scavenging activity was observed, and the highest antioxidant activity was obtained with Alcalase® (1.40 and 3.47 μmol Trolox equivalent/mg protein, for 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and oxygen radical absorbance capacity, respectively) compared with PPP (0.55 and 1.03 μmol Trolox/mg protein). Nevertheless, the IC50 values were lower than those often observed for antioxidant hydrolysates from plant proteins. PEG/citrate buffer system is valuable to purify Pseudomonas proteases from the fermented broth, and the purified protease could be promising to produce antioxidant protein hydrolysates.

Extraction of protease from Aspergillus tamarii URM 4634 in aqueous two-phase system under continuous and discontinuous process

Aqueous two-phase systems have been studied for almost a century to separate biomolecules in harmless conditions. Proteases produced by Aspergillus tamarii URM 4634 were extracted in polyethylene glycol (PEG)/phosphate aqueous two-phase system under discontinuous and continuous (perforated rotative discs column) process. On the discontinuous process, it was evaluated the effect of operational conditions (PEG molar mass and its concentration, phosphate concentration and pH) over the partition coefficient, activity yield and purification factor. Protease partitioned to PEG-phase with partition coefficients up to 55.73. The best process parameters were 17.5% of PEG, with molar mass 8000 g·mol−1, 15% of phosphate salt at pH 6, with 113.15% of activity yield and purification factor of 2.62. Under continuous extraction, hold up data showed that 57.1% of the discontinuous phase was available for protein extraction. Further, separation achieved 90.0% of efficiency. The yields surpassed 100% in almost all runs, and the best purification factor was 1.84, with both flows of 2 mL·min−1. Thus, the best operational conditions reached an activity yield of 95.3% and 90.0% of separation efficiency. Hence, aqueous two-phase system PEG/phosphate extraction is an efficient process for separation of proteases produced by Aspergillus tamarii URM 4634, under continuous extraction likewise under discontinuous process.

Synthesis and Characterization of Lignin-Based Polyurethane as a Potential Compatibilizer

Lignin is one of the most abundant biopolymer on earth. It has polar and non-polar side due to its hyperbranched structure, but the polarity of lignin has a higher tendency than non-polarity. Lignin has potential to be compatibilizer if the portion of non-polar can be increased. This research is focused on investigate the synthesis of lignin-based polyurethane to enhance the portion of non-polarity in lignin. Lignin-based polyurethane was prepared by reacting variation 4,4'-Methylenebis(cyclohexyl isocyanate) (HMDI) and polyethylene glycol (PEG), then lignin was added to the reaction. In this study, the structure of lignin-based polyurethane was confirmed by NMR and FTIR. NMR and FTIR showed that lignin successfully grafted. NMR, also used to investigate the variation molar mass of PEG and isocyanate contents effects to polarity of lignin-based polyurethane. The polarity of lignin-based polyurethane decrease as the composition of HMDI and molecular weight of PEG increase. This result also occurs on the sessile drop test that used to determine surface tension of lignin-based polyurethane. The thermal properties of lignin-based polyurethane also investigate using STA. Based on STA, enhancement of composition of HMDI and PEG increase thermal degradation and resistance of lignin-based polyurethane.

PEG-sodium citrate aqueous two-phase systems to in situ recovery of protease from Aspergillus tamarii URM4634 by extractive fermentation

Abstract This paper investigates the influence of polyethylene glycol (PEG) molar mass, concentrations of PEG and sodium citrate, and pH, in situ recovery on protease produced by Aspergillus tamarii URM4634. A biochemical characterization study was conducted, and thermodynamic parameters were determined in the test which used 8000 (g/mol) PEG molar mass, PEG concentration 24% (w/w), sodium citrate concentration 20% (w/w) and pH 6.0 with partition coefficient of 35.0, activity yield of 98.4 and concentration factor of 2.14. This PEG-phase had an optimum pH and temperature of 8.0 and 60 °C, respectively, being inhibited by EDTA (83.3%) which indicated that this's a metalloprotease. The thermodynamic studies of the protease had an activation energy of 19.01 kJ/mol and a deactivation energy of 29.6 kJ/mol. It was in this range that the following estimates could be made: enthalpy of ΔH*d 29.7 kJ/mol, entropy of ΔS*d − 265.0 kJ/mol K and Gibbs free energy of 120.0 ≤ ΔG*d ≤ 125.9 kJ/mol. These results show a possible scaling-up of the bioreactor process which, under the conditions in the shaker flask, showed considerable values in the integrated production and extraction process, thus demonstrating the potential of this process for obtaining a high recovery of protease and similar products.

Application of aqueous biphasic systems as strategy to purify tannase from Aspergillus tamarii URM 7115

ABSTRACTThe aims of the current study are to assess the influence of polyethylene glycol (PEG) concentration, molar mass, pH, and citrate concentrations on aqueous biphasic systems based on 24 factorial designs, as well as to check their capacity to purify tannase secreted by Aspergillus tamarii URM 7115. Tannase was produced through submerged fermentation at 26°C for 67 h in Czapeck-Dox modified broth and added with yeast extract and tannic acid. The factorial design was followed to assess the influence of PEG molar mass (MPEG 600; 4,000 and 8,000 g/ mol), and PEG (CPEG 20.0; 22.0 and 24.0% w/w) and citrate concentrations (CCIT 15.0, 17.5, and 20.0%, w/w), as well as of pH (6.0, 7.0, and 8.0) on the response variables; moreover, partition coefficient (K), yield (Y), and purification factor (PF) were analyzed. The most suitable parameters to purify tannase secreted by A. tamarii URM 7115 through a biphasic system were 600 (g/mol) MPEG, 24% (w/w) CPEG, 15% (w/w) CCIT at pH 6.0 and they resulted in 6.33 enzyme partition, 131.25% yield, 19.80 purification factor and 195.08 selectivity. Tannase secreted by A. tamarii URM 7115 purified through aqueous biphasic systems composed of PEG/citrate can be used for industrial purposes, since it presents suitable purification factor and yield.

Polyethylene glycol as an osmotic regulator in dough with reduced salt content

In this study, polyethylene glycol (PEG) was used as an osmotic regulator in dough to investigate the effects of reduced NaCl content on dough properties. The effects of water content (±10% of Farinograph absorption) and PEG's molar mass on dough machinability (stickiness, work of adhesion and cohesiveness) were estimated using a full factorial design. PEG with different molar masses (400, ∼1600, and 3350 g/mol) was added at a concentration of 1 g/100 g flour. All properties measured were affected significantly by the variation of water content and PEG's molar mass. At lower levels of dough hydration, stickiness increased with an increase in PEG's molar mass, whereas the opposite trend was observed at higher levels of dough hydration, suggesting there may be an optimum between the water restriction effect induced by PEG and dough's physical properties. The interaction effect was significant for both stickiness and work of adhesion, showing interdependence between water content, PEG molecule size and dough physical properties. The effects of PEG's concentration and molar mass on dough machinability were also assessed by full factorial design. Increasing PEG's molar mass and concentration improved dough machinability, that is, dough with reduced stickiness was obtained.

Effects of Salt, Polyethylene Glycol, and Water Content on Dough Rheology for Two Red Spring Wheat Varieties

In this research, the relationship between dough rheology and water behavior was investigated in response to two osmotic regulators, salt (NaCl) and polyethylene glycol (PEG), using two Canadian Western Red Spring (CWRS) wheat varieties (Harvest and Pembina). The effects of NaCl (0.5, 1.0, and 1.5 g/100 g of flour) and PEG 400 (2.5, 5.0, and 7.5 g/100 g of flour) on dough rheology (oscillatory and creep) were estimated by using a central composite design. Variation of NaCl showed a significant effect on the phase angle δ, indicating that increasing the NaCl resulted in a more elastic dough. The opposite trend was observed with the addition of PEG. PEG 400 exerted a softening effect owing to plasticization, so that a more compliant liquid‐like dough was produced. The effects of water content (±10% of farinograph absorption) and PEG molar mass on dough rheology and freezable water content were estimated by using a full factorial design. PEGs with different molar mass (400, ≈1,600, and 3,350 g/mol) were added at a concentration of 1 g/100 g of flour. The water content significantly affected all dough rheological attributes, whereas PEG molar mass had no effect. The complex shear modulus (G*) decreased with increasing water content, and dough creep compliance (Jmax) increased. The elastic response of dough, determined as the relative elastic part (Jel) decreased with increasing water content. A high correlation was found between the freezable water content and dough rheological attributes.