Initial Bovine Serum Albumin Concentration Research Articles

Modelling and optimization of bovine serum albumin adsorption on calcium bentonite using box-behnken experimental design method

The purpose of this study is to investigate and optimize the process parameters for bovine serum albumin (BSA) adsorption onto calcium bentonite (CaB) using the Box-Behnken experimental design method. Calcium bentonite was characterized using FT-IR, SEM, XRD, zeta potential measurements, and Boehm titration methods. The BSA adsorption capacity of calcium bentonite was modelled with respect to pH (2.8, 4.8, and 6.8), temperature (25 °C, 32.5 °C, and 40 °C), and initial protein concentration (0.1–1.2 mg ml−1) using the Box-Behnken experimental design method. The Design Expert 13.0 software was used to optimize the process conditions and obtain three-dimensional response surface graphs. A regression model, which gives the relationship between the process parameters and BSA adsorption capacity, was obtained using Design Expert software. The developed model showed that the most effective parameter on adsorption was the initial protein concentration followed by pH and temperature. The maximum adsorption capacity was obtained about 171 mg/g under optimal conditions (pH 4.8, 40 °C, and 1 mg ml−1 of initial BSA concentration). BSA adsorption onto CaB fit the pseudo-second order kinetic model. This study showed that process parameters for BSA adsorption can be effectively investigated and optimized using the Box-Behnken experimental design method with a fewer number of experiments.

Preparation of poly(2‐hydroxyethyl methacrylate)‐grafted chitosan‐montmorillonite superabsorbent nanocomposite for adsorption of bovine serum albumin

AbstractIn this paper, we examined adsorption process of bovine serum albumin (BSA) on [p(HEMA)‐g‐CTS]/MMT ([poly(2‐hydroxyethyl methacrylate)‐graft‐chitosan]/montmorillonite) superabsorbent nanocomposite. [p(HEMA)‐g‐CTS]/MMT superabsorbent nanocomposite was synthesized via free radical polymerization. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA) techniques, and also swelling test have been utilized for the structural characterization of the synthesized [p(HEMA)‐g‐CTS]/MMT superabsorbent nanocomposite. The influence of numerious adsorption parameters (initial BSA concentration, contact time, pH, sorbent amount, temperature, and ionic strength) on adsorption process were evaluated. Adsorption results showed that the superabsorbent nanocomposite had high affinity to BSA, and maximum adsorption capacity of [p(HEMA)‐g‐CTS]/MMT superabsorbent nanocomposite is 75.8 mg/g. The BSA adsorption results showed that the adsorption kinetics parameters was found to be suitable for the pseudo‐second‐order kinetic adsorption model and the equilibrium BSA adsorption data were explicated according to the Freundlich adsorption isotherm model.

Preparation and Characterization of Protein Molecularly Imprinted Poly (Ionic Liquid)/Calcium Alginate Composite Cryogel Membrane with High Mechanical Strength for the Separation of Bovine Serum Albumin.

In order to improve the mechanical strength and imprinting efficiency, a novel bovine serum albumin (BSA) molecularly imprinted poly(ionic liquid)/calcium alginate composite cryogel membrane (MICM) was prepared. The results of the tensile test indicated that the MICM had excellent mechanical strength which could reach up to 90.00 KPa, 30.30 times higher than the poly (ionic liquid) membrane without calcium alginate; the elongation of it could reach up to 93.70%, 8.28 times higher than the poly (ionic liquid) membrane without calcium alginate. The MICM had a very high welling ratio of 1026.56% and macropore porosity of 62.29%, which can provide effective mass transport of proteins. More remarkably, it had a very high adsorption capacity of 485.87 mg g-1 at 20 °C and 0.66 mg mL-1 of the initial concentration of BSA. Moreover, MICM also had good selective and competitive recognition toward BSA, exhibiting potential utility in protein separation. This work can provide a potential method to prepare the protein-imprinted cryogel membrane with both high mechanical strength and imprinting efficiency.

Tannic acid modified iron oxide nanoparticles and its application in protein adsorption: isotherm, kinetic, and thermodynamic study

Iron oxide nanoparticles, such as Fe3O4, are commonly used in various applications, such as drug delivery, magnetic fluid, water purification, and enzyme immobilization. These applications require protein to be adsorbed on the surface of iron oxide nanoparticles. However direct utilization of iron oxide nanoparticles has several drawbacks, thus modification of iron oxide nanoparticles is usually done. In this study, we reported surface modification of Fe3O4 using tannic acid to adsorb bovine serum albumin (BSA). The effect of modification and the BSA adsorption on the Fe3O4 was characterized using Fourier Transform Infrared Spectroscopy, X-ray Diffraction, Scanning Electron Microscopy, and Transmission Electron Microscopy. Furthermore the adsorption performance of modified and unmodified Fe3O4 was investigated at various initial pH, BSA concentration, and adsorption temperature. Several kinetic and isotherm adsorption models were used to describe the adsorption in this study. It was found that highest BSA adsorption was obtained at pH 4.8, near BSA’s isoelectric point. The adsorption kinetics followed the pseudo 2nd order model and reached equilibrium after 210 min adsorption. Based on Langmuir monolayer adsorption capacity, it was found that tannic acid modified Fe3O4 had 5 times higher adsorption capacity (222 mg/g), compared to unmodified Fe3O4 (46 mg/g). Furthermore, from the thermodynamic study, it was suggested that the BSA adsorption was endothermic, spontaneous, and random in nature.

Microalgal Bioprocess Toward the Production of Microalgal Oil Loaded Bovine Serum Albumin Nanoparticles.

Microalgal biotechnology has increased rapidly owing to have high value bioactive compounds and numerous consumer products that can be utilized from microalgae. With the development of novel cultivation and processing methods, microalgal biotechnology can meet the high demands of food, energy and pharmaceutical industries. In this context, especially for food and pharmaceutical applications, encapsulation of microalgal bioactive compounds is carried out to protect the compound from oxidation and degradation. In this study, a microalgal production process was carried out and microalgal oil loaded bovine serum albumin (BSA) nanoparticle production using glucose as cross-linking agent was investigated. The influences of different process parameters such as initial BSA concentration, glucose concentration and desolvation temperature on the size of BSA nanoparticles were investigated to achieve very small size nanoparticles. Furthermore, data obtained from the experiments were assessed statistically to model the process. It was found that the obtained nanoparticles showed spherical shape with the mean particle size of around 200-300nm with zeta potential of about - 23mV. Also, stability test showed that, there was not any change in particle size for one month storage and nanoparticle structure enhance the protection of microalgae oil from oxidation. At last, antibacterial effect of nanoparticles was presented against E. coli ATCC 8739 and L. monocytogenes ATCC 13932. In here, we demonstrated a microalgal bioprocess which consists of microalgae production to obtain microalgal oil riched in bioactive and, encapsulation of microalgal oil to protect it from environmental conditions.

Affinity Membranes and Monoliths for Protein Purification.

Affinity capture represents an important step in downstream processing of proteins and it is conventionally performed through a chromatographic process. The performance of this step highly depends on the type of matrix employed. In particular, resin beads and convective materials, such as membranes and monoliths, are the commonly available supports. The present work deals with non-competitive binding of bovine serum albumin (BSA) on different chromatographic media functionalized with Cibacron Blue F3GA (CB). The aim is to set up the development of the purification process starting from the lab-scale characterization of a commercially available CB resin, regenerated cellulose membranes and polymeric monoliths, functionalized with CB to identify the best option. The performance of the three different chromatographic media is evaluated in terms of BSA binding capacity and productivity. The experimental investigation shows promising results for regenerated cellulose membranes and monoliths, whose performance are comparable with those of the packed column tested. It was demonstrated that the capacity of convective stationary phases does not depend on flow rate, in the range investigated, and that the productivity that can be achieved with membranes is 10 to 20 times higher depending on the initial BSA concentration value, and with monoliths it is approximately twice that of beads, at the same superficial velocity.

Magnetic carbon nanotube modified with polymeric deep eutectic solvent for the solid phase extraction of bovine serum albumin

This article described the fabrication of novel magnetic carbon nanotube modified with polymeric deep eutectic solvent (M-CNT@PDES) and its application as extractant for the magnetic solid phase extraction (MSPE) of bovine serum albumin (BSA). The physicochemical properties and morphology of M-CNT@PDES were characterized by X-ray diffraction (XRD), vibrating sample magnetometer (VSM), thermo-gravimetric analysis (TGA), zeta potentials, fourier transform infrared spectrometry (FT-IR) and transmission electron microscope (TEM). Afterwards, several parameters such as pH value, initial concentration of BSA, extraction time, ionic strength and extraction temperature were optimized. The results indicated that the modification of PDES significantly improved the extraction performance for BSA, and the maximum extraction capacity was 225.15 mg/g under the optimized conditions. In addition, 0.20 mol/L NaCl-PBS solution was chosen as the appropriate eluent, and favourable elution rate (81.22%) was obtained. Circular dichroism spectroscopy (CD) indicated that the secondary structure of BSA has not changed during extraction and elution. The regenerative experiment and application in real calf serum confirmed the outstanding durability and practical application ability of M-CNT@PDES. All of above verified that the proposed M-CNT@PDES coupled with MSPE method has great application potential for the pre-concentration of biomolecules.

Fe2O3–SiO2 Core–Shell Nanoparticles Conjugated With Bovine Serum Albumin

This paper presents a systematic study of bovine serum albumin (BSA) conjugation on the amine-functionalized magnetic nanoparticles (MNPs) and the effects of various experimental parameters on the conjugation process. The amine-functionalized Fe2O3 NPs with silica shell were synthesized through surface modification. The BSA conjugation on the amine-functionalized Fe2O3 NPs was achieved through covalent binding via carbodiimide activation. Morphology and magnetic properties of the nanoparticles were investigated. The influence of reaction time, the initial protein concentration, and the temperature on BSA conjugation was studied. The increased reaction time promoted the conjugation of BSA on the Fe2O3 NPs and finally reached the saturation at 43.4 mg/g. The initial BSA concentration can increase the amount of conjugated BSA. The temperature exhibited no significant effect on the conjugation process. The results are useful for designing effective fabrication strategy for protein-conjugated nanomaterials.

Evaluation of agarose-entrapped magnetic nanoparticles influence on protein adsorption isotherm and kinetics using nickel-iminodiacetic acid ligand

Abstract Employing magnetic beads for immobilized metal affinity chromatography application was studied with the approach of magnetic effects investigation. Hence, fabricated magnetic nanoparticles-carrying beads were functionalized with Ni(II)-iminodiacetic acid (IDA). BET-BJH results showed that nanoparticles affected pore sizes lower than 10 nm. Therefore, the pore blockage by protein molecules is considered as an outcome of the new pore diameter in magnetic beads. In accordance, bovine serum albumin (BSA) adsorption isotherms revealed a significant difference between magnetic and nonmagnetic beaded matrices. For nonmagnetic beads, adsorption isotherm followed Langmuir model. However, one step increase in adsorption isotherm for initial BSA concentration from 0.5 mg/ml to 0.8 mg/ml was observed on magnetic beads due to pore blockage by proteins. BSA Adsorption kinetics on beads was found to follow the assumptions of an intraparticle diffusion-controlled pseudo-second order mechanism, with higher adsorption rate constants at lower adsorbate concentrations. Furthermore, though the same IDA density on both non/magnetic beads, presence of magnetic nanoparticles reduced the required equilibrium time (up to 60 min), the saturation path of BSA adsorption breakthrough curves, dynamic binding capacity and the number of theoretical plates. It is concluded that magnetic characteristic of composite agarose adsorbent carrying Fe 3 O 4 nanoparticles affects protein’s conformation. Thus, BSA travel toward ligand is enhanced and sped up.

An enhanced immobilization of BSA biomolecule on anionic hydrogels: swelling and adsorption modeling

The three-dimensional structure of hydrogels plays a leading role in several areas of applications. The hydrogels are more and more used as systems of immobilized and controlled release of biomolecules in biotechnology and bio-pharmacy industries. To improve protein adsorption capacity in poly(acrylamide) hydrogels, maleic acid co-monomer was included into the reaction mixture during hydrogel synthesis. So, hydrogels of poly(acrylamide) and its copolymers with diprotic maleic acid were prepared by copolymerization and chemical crosslinking with N,N′-methylene bis-acrylamide. Swelling behavior in distilled water, in physiological saline and in bovine serum albumin (BSA) solutions was studied. Influence of initial BSA concentration on hydrogel swelling and BSA adsorption was investigated. The high amount of maleic acid present in the hydrogels has a significant effect on the swelling behavior and BSA adsorption. Results showed that the pH sensitivity of hydrogels resulted in the high amount of adsorbed BSA. The adsorption isotherms were described by Langmuir and Freundlich models. The thermodynamic parameter (ΔG ads 0 ) was determined for all obtained hydrogels. We demonstrated the favorable character and reversibility of the BSA adsorption process.

Fabrication of Gelatin-Based Electrospun Composite Fibers for Anti-Bacterial Properties and Protein Adsorption.

A major goal of biomimetics is the development of chemical compositions and structures that simulate the extracellular matrix. In this study, gelatin-based electrospun composite fibrous membranes were prepared by electrospinning to generate bone scaffold materials. The gelatin-based multicomponent composite fibers were fabricated using co-electrospinning, and the composite fibers of chitosan (CS), gelatin (Gel), hydroxyapatite (HA), and graphene oxide (GO) were successfully fabricated for multi-function characteristics of biomimetic scaffolds. The effect of component concentration on composite fiber morphology, antibacterial properties, and protein adsorption were investigated. Composite fibers exhibited effective antibacterial activity against Staphylococcus aureus and Escherichia coli. The study observed that the composite fibers have higher adsorption capacities of bovine serum albumin (BSA) at pH 5.32–6.00 than at pH 3.90–4.50 or 7.35. The protein adsorption on the surface of the composite fiber increased as the initial BSA concentration increased. The surface of the composite reached adsorption equilibrium at 20 min. These results have specific applications for the development of bone scaffold materials, and broad implications in the field of tissue engineering.

Development of amphoteric alginate/aminated chitosan coated microbeads for oral protein delivery

A new amphoteric biopolymer carrier based on alginate and aminated chitosan coated microbeads (Alg/AmCS) was developed and characterized for bovine serum albumin (BSA) protein delivery. The amphoteric character was investigated through studying the swelling and in vitro BSA release behaviors of the developed microbeads in simulated gastric (SGF; pH1.2), intestinal (SIF; pH6.8), and colonic (SCF; pH7.4) fluids. The pH sensitivity was found to depend on the amount of AmCS in the coating medium. The results were interpreted from the view of the individual pH sensitivity of alginate and aminated chitosan in addition to the ionic interaction between them under the studied pHs. Besides; it was found that the BSA loading efficiency (LE) exceeded 82% regardless of the initial concentration of BSA. The released amount of BSA reached approximately 63% and 86% in SIF and SCF, respectively, using 0.25% AmCS. The stability of alginate microbeads in SCF was improved with increasing AmCS concentration in the coating medium up to 2%. Furthermore, the developed microbeads demonstrated their ability for biodegradation in addition to their antibacterial activities against selected bacterial strains. The results clearly suggested that Alg/AmCS coated microbeads could be suitable carriers for site-specific protein delivery in the intestinal and colon tracts.

Magnetic hydrogel beads based on PVA/sodium alginate/laponite RD and studying their BSA adsorption

In this study double physically crosslinked magnetic hydrogel beads were developed by a simple method including solution mixing of sodium alginate and poly(vinyl alcohol) (PVA) containing magnetic laponite RD (Rapid Dispersion). Sodium alginate and PVA were physically crosslinked by Ca2+ and freezing-thawing cycles, respectively. Magnetic laponite RD nanoparticles were incorporated into the system to create magnetic response and strengthen the hydrogels. All hybrids double physically crosslinked hydrogel beads were stable under different pH values without any disintegration. Furthermore, adsorption of bovine serum albumin (BSA) on the hydrogel beads was investigated on the subject of pH, ion strength, initial BSA concentration, and temperature. Nanocomposite beads exhibited maximum adsorption capacity for BSA at pH=4.5. The experimental adsorption isotherm data were well followed Langmuir model and based on this model the maximum adsorption capacity was obtained 127.3mgg−1 at 308K. Thermodynamic parameters revealed spontaneous and monolayer adsorption of BSA on magnetic nanocomposites beads.

Protein nanoparticle interaction: A spectrophotometric approach for adsorption kinetics and binding studies

Investigating the protein nanoparticle interaction is crucial to understand how to control the biological interactions of nanoparticles. In this work, Model protein Bovine serum albumin (BSA) was used to evaluate the process of protein adsorption to the gold nanoparticles (GNPs) surface. The binding of a model protein (BSA) to GNPs was investigated through fluorescence quenching measurements. The strong affinities of BSA for GNPs were confirmed by the high value of binding constant (Ks) which was calculated to be 2.2 × 1011 L/mol. In this consequence, we also investigated the adsorption behavior of BSA on GNPs surface via UV–Vis spectroscopy. The effect of various operational parameters such as pH, contact time, initial BSA concentration, and temperature on adsorption of BSA was investigated using batch adsorption experiments. Kinetics of adsorption was found to follow the pseudo-second order rate equation. The suitability of Freundlich and Langmuir adsorption models to the equilibrium data was investigated. The equilibrium adsorption was well described by the Freundlich isotherm model. The maximum adsorption capacity for BSA adsorbed on GNPs was 58.71 mg/g and equilibrium constant was 0.0058 calculated by the Langmuir model at 298 K and pH = 11.0. Thermodynamic parameters showed that the adsorption of BSA onto GNPs was feasible, spontaneous, and exothermic.

Protein adsorption using novel carboxymethyl-curdlan microspheres

Carboxymethyl-curdlan as a water soluble curdlan derivative, was synthesized in an aqueous alkaline medium using monochloroacetic acid. Novel carboxymethyl-curdlan (CC) microspheres were prepared by the method of W/O/W emulsion. The chemical and morphological structures of CC microspheres were investigated by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and particle size analysis. The CC microspheres were spherical, free flowing, non-aggregated and uniform mono-disperse with diameter of 260μm. The prepared CC microspheres were applied to adsorbing Bovine serum albumin (BSA) as model protein. Factors influencing the adsorption of BSA such as solution pH, temperature, initial BSA concentration and ionic strength were examined by batch experiments. The maximum adsorption capacity was calculated as 168mg/g under optimal conditions including BSA initial concentration (4mg/mL), pH (4.7), adsorption time (9h) and temperature (35°C). The adsorption isotherm followed the Langmuir model and the adsorption kinetics fitted the pseudo-second-order model. In addition, the CC microspheres can be also regenerated and re-used.

Cost-effective nanoporous Agar–Agar polymer/Nickel powder composite particle for effective bio-products adsorption by expanded bed chromatography

In the present work a novel kind of dense nanoporous composite matrix for expanded bed application has been successfully first prepared with Nickel powder as a densifier and was covered with Agar–Agar layer as a skeleton, through the method of water-in-oil emulsification. Agar–Agar is a porous and inexpensive polymer. In order to fabricate cost-effective adsorbent with favorable qualities Agar–Agar polymer was used. Thereafter, the customized composite particle was modified by pseudo-affinity dye–ligand, Reactive Blue 4 (RB4), aimed at preparing a pseudo-affinity adsorbent (RB4-Agar-Ni) for bioprodut adsorption from aqueous solution. Bovine Serum Albumin (BSA) was selected as a model protein to investigate the adsorption behavior in batchwise and expanded bed chromatography, and the obtained results were evaluated with that of Streamline™ (Amersham–Pharmacia Biotech, Sweden). Spherical appearance and porous structure of composite particles were observed by the optical microscope (OM) and scanning electronic microscope (SEM). The results suggested that the matrices followed the logarithmic normal size distribution with the range of 65–300μm and average diameter of 126.81–151.47μm, proper wet density of 1.64–2.78g/ml, water content of 62.74–34%, porosity of 98–90% and pore size of about 38–130nm. For better comprehension of the impact of solid phase properties on the performance of the expanded bed, the expansion and hydrodynamic properties of a composite matrix with a series of densities was evaluated and estimated by the retention time distribution method (RTD) in an expanded bed and was compared with that of other matrices. According to obtained results the expansion factors under the same fluid velocity decreased by increasing the matrix density. Moreover, the axial dispersion coefficient (Dax) is the most appropriate parameter for evaluating the stability of expanded bed, on various operating conditions, such as different flow velocity, bed expansion degree, viscosity of the liquid phase and the density of adsorbent. It was observed that the application of matrix with high density was proper for high operation, fluid velocity, since the addition of densifier improves the rigidity of the matrix. Three momentous factors, pH, ionic strength and initial concentration of BSA were analyzed. The best results showed that the adsorption equilibrium isotherms seems to follow a typical Langmuir isotherm and also the maximum adsorption capacity (qm) of BSA on RB4-Agar-Ni (64.01mg/ml adsorbent) was higher than that on RB4-Streamline commercial adsorbent (about 54mg.ml adsorbent). Additionally kinetic adsorption processes were characterized by the pseudo-first-order and pseudo-second-order kinetics equations. The experimental data followed the pseudo-first-order kinetic equation. Also the breakthrough curves were investigated. It was found that dynamic binding capacity (DBC) decreased with increasing the flow rate and the values of DBC decreased from 21.08 to 11.15mg/ml adsorbent when the density of composite beads increased from 1.64 to 2.78g/ml. All results indicate that the prepared composite is promising for efficient bioproduct adsorption with good hydrodynamic characteristics, high stability and it is suitable for expanded bed usage as a cost-effective adsorbent.

In vitro evaluation of spray‐dried chitosan microspheres crosslinked with pyromellitic dianhydride for oral colon‐specific delivery of protein drugs

ABSTRACTChitosan microspheres have been prepared using a spray‐drying method, and crosslinked with pyromellitic dianhydride. The chemical structure of the modified chitosan was characterized by FTIR spectroscopy and solid state 13C NMR analysis. The particle size and morphology of the crosslinked chitosan were investigated. These microspheres were evaluated for colon‐specific delivery of bovine serum albumin (BSA) as a model protein drug. The results indicate that the drug was released as follows: 37.1 ± 2.8% after 2 h in SGF, 73.1 ± 4.8% after 8 h (2 h in SGF+ 6 h in SIF), and 80.9 ± 4.1% after 12 h in SCF. The effect of β‐glucosidase on the drug release was also examined. The encapsulation efficiency was decreased from 88.4 ± 3.1% to 62.8 ± 2.9%, with increasing BSA concentration. Loading capacity was significantly increased from 6.3 ± 0.3% to 41.8 ± 4.1% by increasing the initial BSA concentration. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40514.

Characteristics of selective fluoride adsorption by biocarbon-Mg/Al layered double hydroxides composites from protein solutions: Kinetics and equilibrium isotherms study

In the study, two novel applied biocarbon-Mg/Al layered double hydroxides composites (CPLDH and CPLDH-Ca) were successfully prepared and characterized by TEM, ICP-AES, XFS, EDS, FTIR, XRD, BET and pHpzc. The fluoride removal efficiency (RF) and protein recovery ratio (RP) of the adsorbents were studied in protein systems of lysozyme (LSZ) and bovine serum albumin (BSA). The results showed that the CPLDH-Ca presented remarkable performance for selective fluoride removal from protein solution. It reached the maximum RF of 92.1% and 94.8% at the CPLDH-Ca dose of 2.0g/L in LSZ and BSA system, respectively. The RP in both systems of LSZ and BSA were more than 90%. Additionally, the RP of CPLDH-Ca increased with the increase of ionic strengths, and it almost can be 100% with more than 93% RF. Fluoride adsorption by the CPLDH-Ca with different initial fluoride concentrations was found to obey the mixed surface reaction and diffusion controlled adsorption kinetic model, and the overall reaction rate is probably controlled by intra-particle diffusion, boundary layer diffusion and reaction process. The adsorption isotherms of fluoride in BSA system fit the Langmuir–Freundlich model well. The BSA has synergistic effect on fluoride adsorption and the degree increased with the increase of the initial BSA concentration.

Effect of Bovine Serum Albumin (BSA) on Enzymatic Cellulose Hydrolysis

Bovine serum albumin (BSA) was added to filter paper during the hydrolysis of cellulase. Adding BSA before the addition of the cellulase enhances enzyme activity in the solution, thereby increasing the conversion rate of cellulose. After 48 h of BSA treatment, the BSA adsorption quantities are 3.3, 4.6, 7.8, 17.2, and 28.3 mg/g substrate, each with different initial BSA concentration treatments at 50 °C; in addition, more cellulase was adsorbed onto the filter paper at 50 °C compared with 35 °C. After 48 h of hydrolysis, the free-enzyme activity could not be measured without the BSA treatment, whereas the remaining activity of the filter paper activity was approximately 41 % when treated with 1.0 mg/mL BSA. Even after 96 h of hydrolysis, 25 % still remained. Meanwhile, after 48 h of incubation without substrate, the remaining enzyme activities were increased 20.7 % (from 43.7 to 52.7 %) and 94.8 % (from 23.3 to 45.5 %) at 35 and 50 °C, respectively. Moreover, the effect of the BSA was more obvious at 35 °C compared with 50 °C. When using 15 filter paper cellulase units per gram substrate cellulase loading at 50 °C, the cellulose conversion was increased from 75 % (without BSA treatment) to ≥90 % when using BSA dosages between 0.1 and 1.5 mg/mL. Overall, these results suggest that there are promising strategies for BSA treatment in the reduction of enzyme requirements during the hydrolysis of cellulose.

Investigation and modeling effective parameters influencing the size of BSA protein nanoparticles as colloidal carrier

Bovine Serum Albumin (BSA) nanoparticles (NPs) with different sizes were prepared using a self-assembly simple coacervation method and cross-linking with glutaraldehyde. Protein NPs were purified with 48,800×g centrifuge followed by dialysis, microfiltration and ultrafiltration. The produced protein NPs were subjected to physical and morphological as well as biochemical characterization tests. Image analysis studies by scanning electron microscopy and atomic force microscopy proved semi-spherically shape of the particles whereas size distribution was measured by photon correlation spectroscopy. The influences of several process parameters such as pH, initial BSA concentration, agitation speed, glutaraldehyde concentration and organic solvent addition rate on the size of protein NPs at different temperature (24°C, 14°C, 4°C) were investigated to achieve a suitable size of NP. Furthermore, mathematical method was implemented to model the experimental data. The mechanistic for preparing protein NPs as well as their characterizations were discussed.