Effective recovery of casein from its highly diluted solution by using a technology of foam fractionation coupled with isoelectric precipitation

Separation and Purification of Recombinant β-Glucosidase with Hydrophobicity and Thermally Responsive Property from Cell Lysis Solution by Foam Separation and Further Purification

The aim of this study was to separate and purify recombinant β-glucosidase (GLEGB) with elastin-like polypeptide (ELP) and graphene-binding peptide (GB) from cell lysis solution by foam separation and further purification. The study of foam property of GLEGB cell lysis solution indicated that it had excellent foaming property and foam stability, which was suitable for foam separation. This could be due to the GB tag with hydrophobicity, which made the recombinant β-glucosidase with GB preferentially adsorb on the surface of bubbles. At optimum operating conditions of foam separation, the enzyme activity recovery of GLEGB could reach 95.63 ± 1.0%. The foam solution of GLEGB was further purified based on the thermally responsive property of the ELP tag, and the purification fold of GLEGB could reach 29.6 ± 0.5 at the optimum operating conditions. The prominent purification effect indicates that this technique is a simple and efficient technique for the separation and purification of recombinant enzymes.

Casein Microgels as Benzydamine Hydrochloride Carriers for Prolonged Release

This research aims to investigate the properties of nano- and micro-sized casein hydrogels crosslinked by sodium tripolyphosphate as drug delivery systems. Benzydamine hydrochloride was chosen as a model hydrophilic drug. The gels were synthesized by varying different parameters: casein concentration, casein/crosslinking ratio, and addition of ethanol as a co-solvent. The electrostatic attractive interactions between the casein and the sodium tripolyphosphate were confirmed by FTIR spectroscopy. The particle sizes was determined by dynamic light scattering and varied in the range between several hundred nanometers and several microns. The yield of the gelation process was high for all investigated samples and varied between 55.3% and 78.3%. The encapsulation efficiency of the particles was strongly influenced by the casein concentration and casein/crosslinker ratio and its values were between 4.6% and 22.4%. The release study confirmed that casein particles are useful as benzydamine carriers and ensured prolonged release over 72 h.

Hydrophobicity, amphilicity, and flexibility: Relation between molecular protein properties and the macroscopic effects of surface activity

Their surface activity enables proteins to form and stabilize foam, which can be used for in situ product separation or foam fractionation. Thus, it would be highly desirable to predict the surface activity of proteins based on their molecular properties like hydrophobicity, amphilicity, or structure on primary, secondary, and tertiary level. Ionic strength and pH were adjusted to gain maximum surface activity. The surface activity decreased in the order α lactalbumin > β‑lactoglobulin > trypsinogen > papain. For the theoretical analysis, the database was extended by including 2 hydrophobins into the investigation, since they are known to exhibit an outstanding surface activity. No relation to the macroscopic behavior was found considering the hydrophobicity. I.e., the non-hydrophobins did not differ significantly from each other, and from the hydrophobins, one was significantly hydrophobic, and the other was significantly hydrophilic. Also, no relations were found considering the amphilicity of the secondary structure elements. However, taking into account the tertiary protein structure, it was found that for most of the proteins investigated, the presence of non-buried amphiphilic secondary structure elements in combination with a certain amount of flexibility correlates with the surface activity.

Nano Encapsulated Curcumin: And Its Potential for Biomedical Applications

Curcumin, a yellow-colored polyphenol extracted from the rhizome of turmeric root, is commonly used as a spice and nutritional supplement. It exhibits many pharmacological activities such as anti-inflammatory, anti-bacterial, anti-cancer, anti-Alzheimer, and anti-fungal. However, the therapeutic application of curcumin is limited by its extremely low solubility in aqueous buffer, instability in body fluids, and rapid metabolism. Nano delivery system has shown excellent potential to improve the solubility, biocompatibility and therapeutic effect of curcumin. In this review, we focus on the recent development of nano encapsulated curcumin and its potential for biomedical applications.

Ascertainment of Surfactin Concentration in Bubbles and Foam Column Operated in Semi-Batch

This paper describes a mathematical model for the convection, diffusion, and balance phenomena for predicting the depletion curves, i.e., variations in the timed surface-active molecule concentration for fractionation processes in bubbles and foam column, operated in semi-batch. The model was applied for the purification of the surfactin solution and the results were compared with experimental data. Gibbs adsorption curves were obtained for the biosurfactant at different temperatures, and then adjusted with estimated parameters, according to the Langmuir adsorption model. The gas bubble sizes were optically determined. The isotherm adsorption parameters and bubble average diameter are crucial for the attainment of the depletion curves, generated by the model described. The results demonstrate that the process is most effective when operating a column with reduced gas flow and low initial concentration. A top product with two or thirty times greater concentration than the initial one was achieved and the highest biosurfactant concentrations were attained for higher operating temperatures. It was also observed that bubble diameter increased with a higher gas flow. The adjustment obtained for the adsorption curves of Gibbs was satisfactory. Therefore, there was evidence that surfactin molecules adsorb in monolayers in the liquid–gas interface.