Chemically modified alginate bead matrix for efficient adsorptive recovery of trypsin from fresh bovine pancreas.

The adsorption of commercial trypsin (Try) onto epichlorohydrin cross-linked alginate-guar gum matrix has been studied at equilibrium in batch and in fixed bed column. Experiments were conducted to study the effect of ionic strength, temperature and to obtain a thermodynamic characterization of the adsorption process. The resulting adsorption isotherm fitted the Hill equation.

Comparison of soybean hull pre-treatments to obtain cellulose and chemical derivatives: Physical chemistry characterization.

The cellulose from soybean hull, a waste without value from the argentine agriculture, was successfully obtained by using two different treatments: the traditional alkaline-bleaching pathway and from a simple pre-alkaline treatment at low temperatures. The comparison of both methods yielded similar results regarding its ability to open the lignin cellulosic structure of the hull and the total elimination of the lignin content. Fourier Transform Infrared spectroscopy (FT-IR), Thermogravimetric analysis (TGA), Scanning electron microscopy (SEM), C nuclear magnetic resonance (C-RMN) and Raman spectroscopy were used to characterize the structures and the properties of cellulose.

Control of the adsorption properties of alginate - guar gum matrix functionalized with epichlorohydrin through the addition of different flexible chain polymers as toll for the chymotrypsinogen isolation.

This work addresses the obtaining and characterization of alginate-guar gum matrix, cross-linked with epichlorohydrin in the presence of different flexible chain polymers: polyvinyl alcohol, polyvinyl pyrrolidine and Pluronic® F68. These matrixes were used for the adsorption of chymotrypsinogen and showed an increasing uptake in presence of the flexible chain polymer in the sense: none < Pluronic 68 < polyvinyl pyrrolidine < polyvinyl alcohol. The adsorption process was found to follow a first order kinetics model and was not influenced by the polymer type.

Application of Fluorescence Emission for Characterization of Albendazole and Ricobendazole Micellar Systems: Elucidation of the Molecular Mechanism of Drug Solubilization Process.

Albendazole (ABZ) and ricobendazole (RBZ) are referred to as class II compounds in the Biopharmaceutical Classification System. These drugs exhibit poor solubility, which profoundly affects their oral bioavailability. Micellar systems are excellent pharmaceutical tools to enhance solubilization and absorption of poorly soluble compounds.

Molecular mechanism of lysozyme adsorption onto chemically modified alginate guar gum matrix.

The equilibrium isotherms and adsorption kinetics of lysozyme (LZ) on epichlorohydrin (Epi) cross-linked alginate-guar gum (Alg-GG) matrix were studied. Adsorption kinetics followed a pseudo-first-order model while the equilibrium isotherm could be represented by the Freundlich equation. The maximal amount of LZ adsorbed onto this matrix was around 2.

Influence of pH on viscoelastic properties of heat-induced gels obtained with a β-Lactoglobulin fraction isolated from bovine milk whey hydrolysates.

A β-Lactoglobulin fraction (r-βLg) was isolated from whey hydrolysates produced with cardosins from Cynara cardunculus. The impact of the hydrolysis process on the r-βLg structure and the rheological properties of heat-induced gels obtained thereafter were studied at different pH values. Differences were observed between r-βLg and commercial β-Lg used as control.

Continuous method to determine the trypsin inhibitor activity in soybean flour.

The determination of trypsin inhibitor (TI) activity is of importance to evaluate the nutritional value of soybean flours. An analytical method, which involves a continuous spectrophotometric rate determination for trypsin activity against the substrate N-benzoyl-DL-arginine p-nitroanilide, is proposed as an alternative to the standard discontinuous assay. Stopping the reaction with acetic acid and a centrifugation/filtration step to decrease turbidity are not required, thus reducing costs and sample preparation time.

Adsorption isotherms, kinetics and thermodynamic studies towards understanding the interaction between cross-linked alginate-guar gum matrix and chymotrypsin.

The adsorption kinetics of chymotrypsin, a pancreatic serine protease, onto an alginate-gum guar matrix cross-linked with epichlorohydrin has been performed using a batch-adsorption technique. The effect of various experimental parameters such as pH, salt presence, contact time and temperature were investigated. The pseudo-first-order and pseudo-second-order kinetic models were used to describe the kinetic data which shows that the adsorption of the enzyme followed the pseudo-second-order rate expression.

Bioactive properties of peptides obtained from Argentinian defatted soy flour protein by Corolase PP hydrolysis.

Enzymatic hydrolysis of soybean meal protein isolate (SPI) obtained under two temperature conditions with Corolase PP was studied, assessing the impact of hydrolysis on potential antioxidant and antihypertensive activities. The protein was isolated from soybean meal under controlled conditions of time and temperature (70 °C, 1h; 90 °C, 30 min). Degree of hydrolysis assessed the progress of hydrolysis at different sampling times.

Physicochemical study of the formation of complexes between pancreatic proteases and polyanions.

The formation of insoluble complexes between proteins and oppositely charged polyelectrolytes was assessed. Two pancreatic enzymes: trypsin and chymotrypsin, and two anionic synthetic polyelectrolytes: polyacrylate and polyvinylsulfonate, were used for the study at the pH range between 3.00 and 5.

Interaction of tannase from Aspergillus niger with polycations applied to its primary recovery.

The interaction of tannase (TAH) with chitosan, polyethyleneimine and Eudragit(®)E100 was studied. It was found that TAH selectively binds to these polycations (PC), probably due to the acid nature of the target protein. TAH could interact with these PC depending on the medium conditions.

Characterization of chymotrypsin-ι-carrageenan complex in aqueous solution: a solubility and thermodynamical stability study.

The aim of this study is to report the results of research work on the molecular mechanism of complex formation between chymotrypsin and a negatively charged natural strong polyelectrolyte, ι-carrageenan, using spectroscopy techniques. The carrageenan-chymotrypsin complex showed a maximal non-solubility at pH around 4.50 with a stoichiometric ratio between 8 and 33 g of chymotrypsin per g of carrageenan.

Partition in aqueous two-phase system: its application in downstream processing of tannase from Aspergillus niger.

Tannase from Aspergillus niger was partitioned in aqueous two-phase systems composed by polyethyleneglycol of molar mass 400, 600 and 1000 and potassium phosphate. Tannase was found to be partitioned toward the salt-rich phase in all systems, with partition coefficients lower than 0.5.

Production, recovery and purification of a recombinant β-galactosidase by expanded bed anion exchange adsorption.

β-Galactosidase is a hydrolase enzyme that catalyzes the hydrolysis of β-galactosides into monosaccharides; its major application in the food industry is to reduce the content of lactose in lactic products. The aim of this work is to recover this enzyme from a cell lysate by adsorption onto Streamline-DEAE in an expanded bed, avoiding, as much as possible, biomass deposition onto the adsorbent matrix. So as to achieve less cell debris-matrix interaction, the adsorbent surface was covered with polyvinyl pyrrolidone.

Influence of stabilizers cosolutes on catalase conformation.

The effects of sucrose, mannitol and betaine on the thermodynamic stability and the conformational state of the catalase enzyme were analyzed in order to understand the molecular mechanism whereby the solutes stabilized the enzyme. Catalase was selected as the model enzyme because it is used in several biotechnological processes. In the presence of each cosolute, our data have shown that there was a significant increase in the thermal stability of catalase.

Isolation of a Aspergillus niger lipase from a solid culture medium with aqueous two-phase systems.

The aim of this work is to find the best conditions to isolate lipase from a solid culture medium of Aspergillus niger NRRL3 strains using aqueous two-phase systems formed with polyethylene glycol and potassium phosphate or polyethylene glycol and sodium citrate. We studied the partitioning of a commercial lyophilizate from A. niger.

Cationic polyelectrolytes-lipases complexes formation as tool for recovery of these enzymes from their natural sources.

In the present paper the formation of complexes between positively charge polyelectrolyte (polyethyleneimine and chitosan) and Candida rugosa lipase from a crude extract and porcine lipase from pancreas commercial homogenate preparations were analyzed. The solubility of lipases-cationic polyelectrolytes formation was dependent on: polyelectrolyte densities electrical charge, polyelectrolyte and enzyme concentrations and salts present in the solution. The lipase was recovered from the non-soluble complex by adding of NaCl at a given pH.

A simple method of chymotrypsin concentration and purification from pancreas homogenate using Eudragit® L100 and Eudragit® S100.

The condition of chymotrypsin (ChTRP)-Eudragit® (Eu) insoluble complex formation was studied with the aim of applying this information to the separation of chymotrypsin from a crude filtrate of bovine pancreas homogenate. The optimal pH of the complex precipitation was 4.60 for ChTRP-Eudragit® L100 and 5.

Aspergillus oryzae alpha-amylase partition in potassium phosphate-polyethylene glycol aqueous two-phase systems.

The aim of this work is to study the partitioning of alpha-amylase from Aspergillus oryzae in polyethylene glycol-potassium phosphate systems formed by polymers of different molecular masses with different total concentrations, several NaCl concentrations and different volume ratio between the phases and at different temperatures. The enzyme was partitioned towards the top phase in the 2000-molecular-mass polyethylene glycol systems and towards the bottom phase in the other systems analyzed with higher molecular mass. The protein-medium interaction parameter (A) was determined; it increased in the same way as PEG molecular mass.

The formation of non-soluble complexes between polyethyleneimine-anions and their potential use to isolate enzymes.

The aqueous solution behavior of polyethyleneimine (a synthetic cationic polymer) in the presence of anions with two or more electrical charges (citrate, phosphate, sulphate, malate, malonate and succinate) was studied by means of turbidimetry and light scattering. Polyethyleneimine forms non-soluble complexes with these anions, which behave as a pseudo-polyampholyte with an isoelectrical pH value dependent on the type of anion. The effect of pH, polymer concentration and ionic strength on the non-soluble complexes formation was examined.

Role of polymer-protein interaction on partitioning pattern of bovine pancreatic trypsinogen and alpha-chymotrypsinogen in polyethyleneglycol/sodium tartrate aqueous two-phase systems.

The partitioning pattern of bovine trypsinogen (TRPz) and alpha-chymotrypsinogen (ChTRPz) was investigated in a low impact aqueous two-phase system formed by polyethyleneglycol (PEG) and sodium tartrate (NaTart) pH 5.00. ChTRPz exhibited higher partition coefficients than TRPz did in all the assayed systems.

Candida rugosa lipase Lip1-polyethyleneglycol interaction and the relation with its partition in aqueous two-phase systems.

The interaction between a lipase from Candida rugosa (Lip1) and polyethyleneglycols of different molecular masses was studied using fluorescence and circular dichroism approaches in order to be applied to the analysis of the enzyme partition mechanism in aqueous two-phase systems of polyethyleneglycol-potassium phosphate. The decrease of the partition coefficients with the polyethyleneglycol molecular mass showed that the enzyme partition is driven by the excluded volume effect and not by the enzyme-polymer interaction. The polymer did not affect the secondary and tertiary structure of the enzyme nor its biological activity.

How flexible polymers interact with proteins and its relationship with the protein separation method by protein-polymer complex formation.

Bovine serum albumin was selected as a model protein to study the molecular mechanism of interaction between flexible polymer with net negative electrical charge (polyvinylsulphonate and polyacrylic acid) and a non-charged polymer such as poly(ethylene) poly(propylene) oxide (molecular mass 8,400) by using spectroscopies techniques combination: fluorescence emission and circular dichroism. Polyvinylsulphonate and polyacrylic acid interact with the protein due to the coulombic interaction between positive charged protein groups such as amine of lysine and histidine. The poly(ethylene)-poly(propylene) oxide increased the hydrophobic microenvironment around the tryptophan residues.

Extraction of trypsin from bovine pancreas by applying polyethyleneglycol/sodium citrate aqueous two-phase systems.

The goal of this work was to determine the optimal conditions for separating trypsin (TRP) from alpha-chymotrypsin (ChTRP) and to apply them for trypsin purification from bovine pancreas by liquid-liquid extraction with polyethyleneglycol/sodium citrate (PEG/NaCit) aqueous two-phase systems. Partitioning behaviours of TRP and ChTRP are demonstrated to be very sensitive to variables such as PEG molecular weight, pH and tie line length. Aqueous two-phase systems (ATPSs) formed by PEG of MW 3350 and NaCit pH 5.

Polyethyleneglycol-pepsin interaction and its relationship with protein partitioning in aqueous two-phase systems.

The interaction between the acidic protein, pepsin, and the non-charged polyethyleneglycol polymer was studied by dynamic light scattering, fluorescence spectroscopy and measurements of the protein thermal stability at neutral pH. Polyethyleneglycol of average molecular mass 1450 showed a higher interaction capacity with the protein than polyethyleneglycol of average molecular mass 8000. Polyethyleneglycol of average molecular mass 1450 showed a molecular mechanism where the interpolymer interaction led to the complex formation.