Partitioning ofCanavalia brasiliensisLectin in Polyethylene Glycol – Sodium Citrate Aqueous Two-Phase Systems

Green Approach for the Simultaneous Synthesis and Separation of Gold Nanoparticles

Gold nanoparticles (AuNPs) have diagnostic and therapeutic applications as they are biocompatible and can be surface-functionalized. The use of organic solvents in the synthesis of AuNPs hampers their applications in the medicinal field. The large-scale production of nanoparticles requires their simultaneous synthesis and separation. Self-assembly of nanoparticles at the fluid-fluid interface facilitates their separation from the bulk and eliminates a downstream processing step. In this work, we exploit this in an aqueous two-phase system (ATPS) to synthesize and separate stable AuNPs. The ATPS was based on polyethylene glycol (PEG) and trisodium citrate dihydrate (citrate) as both these compounds can reduce Au ions. After the synthesis of nanoparticles, using one of the solutes, a complementary solution containing the other solute is added to form a two-phase system to facilitate self-assembly at the interface. The nanoparticles synthesized in different phases are characterized using UV-visible spectroscopy, scanning electron microscopy, and transmission electron microscopy. The AuNPs synthesized using the citrate solution are found to be unstable. Particles synthesized using the ATPS with PEG-600 are trapped at the interface while those using PEG-6000 remain in the bulk. Continuous synthesis and separation of nanoparticles in slug flow in a millichannel are demonstrated as a first step for large-scale controlled synthesis.

Extraction behaviors of aqueous PEG impregnated resin system in terms of impregnation stability and recovery via protein impregnated resin interactions on bovine serum albumin

Background

Current advances in biotechnology have been looked at as alternative approaches towards the limited product recovery due to time- and cost-consuming drawbacks on the conventional purification methods. This study aimed to purify bovine serum albumin (BSA) as an exemplary target product using an aqueous impregnated resin system (AIRS). This method implies the concept of hydrophobicity of polymer that impregnated into the resins and driven by electrostatic attractions and hydrophilicity of aqueous salt solution to extract the target product.

Methods

The extraction behaviors of impregnation in terms of stability and adsorption kinetics via protein-aqueous polymer impregnated resin were studied. Impregnation stability was determined by the leaching factor of polyethylene glycol (PEG). The major factors such as PEG molecular weights and concentration, pH of aqueous salt solution, extraction methods (sonication and agitation) and types of adsorbent material and concentration of aqueous salt phase influencing on partitioning of biomolecule were also investigated.

Results

For impregnation stability, the leaching factor for Amberlite XAD4 did not exceed 1%. The scanning electron microscopy (SEM) image analysis of Amberlite XAD4 attributes the structural changes with impregnation of resins. For adsorption kinetics, Freundlich adsorption isotherm with the highest R² value (0.95) gives an indication of favorable adsorption process. Performance of AIRS impregnated with 40% (w/w) of PEG 2000 was found better than aqueous-two phase system (ATPS) by yielding the highest recovery of BSA (53.72%). The outcomes of this study propound the scope for the application of AIRS in purification of biomolecules.

Aqueous two phase based selective extraction of mannose/glucose specific lectin from Indian cultivar of Pisum sativum seed

Pisum sativum lectin (Psl) being a high-value protein has marked its application in the biomedical and therapeutic field. Aqueous two phase extraction (ATPE) was implemented as a selective partitioning technique for the partial purification of Psl from its seeds. PEG/citrate based biodegradable aqueous two phase system (ATPS) was screened and the factors such as the type and concentration of citrate salts, molar mass and concentration of polyethylene glycol (PEG), tie line length (TLL) and additive (NaCl) concentration, pH, crude load and volume ratio were studied for the selective partition of Psl. The Psl was successfully extracted to the top phase in the ATPS formed with 18% PEG 6000/16% sodium citrate at 41.01% TLL, 2% NaCl and pH of 7.5. A volume ratio of 0.76 and a crude load of 20% showed maximum activity yield of 122.12% with the purification factor of 16.26. The subunits of Psl namely α and β were identified with a molecular weight of 6 and 18 kDa respectively during the purity analysis using SDS PAGE and HPLC.

Eco-Innovation in Reusing Food By-Products: Separation of Ovalbumin from Salted Egg White Using Aqueous Two-Phase System of PEG 1000/(NH₄)₂SO₄

For the purpose of reducing pollution and the rational use of salted egg white, which is a byproduct of the manufacturing process of salted egg yolk, an aqueous two-phase system (ATPS) composed of polyethylene glycols (PEG 1000) and (NH₄)₂SO₄ was investigated to selectively separate ovalbumin (OVA) from salted egg white. With the aim of optimizing the selective separation of OVA using ATPS, a response surface method (RSM) experiment was carried out on the basis of a single-factor experiment. The OVA was characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS⁻PAGE), reversed-phase high-performance liquid chromatography (RP-HPLC), liquid chromatography-nano electrospray ionization mass spectrometry (Nano LC-ESI-MS/MS), and Fourier transform infrared spectroscopy (FT-IR). Under the optimal conditions, the recovery yield of OVA through ATPS (Y) and the purity of OVA (P) could reach 89.25% and 96.28%, respectively. In conclusion, OVA was successfully separated from the salted egg white by PEG/(NH₄)₂SO₄ ATPS.

ConA-Like Lectins: High Similarity Proteins as Models to Study Structure/Biological Activities Relationships

Lectins are a widely studied group of proteins capable of specific and reversible binding to carbohydrates. Undoubtedly, the best characterized are those extracted from plants of the Leguminosae family. Inside this group of proteins, those from the Diocleinae subtribe have attracted attention, in particular Concanavalin A (ConA), the best-studied lectin of the group. Diocleinae lectins, also called ConA-like lectins, present a high similarity of sequence and three-dimensional structure and are known to present inflammatory, vasoactive, antibiotic, immunomodulatory and antitumor activities, among others. This high similarity of lectins inside the ConA-like group makes it possible to use them to study structure/biological activity relationships by the variability of both carbohydrate specificity and biological activities results. It is in this context the following review aims to summarize the most recent data on the biochemical and structural properties, as well as biological activities, of ConA-like lectins and the use of these lectins as models to study structure/biological activity relationships.

Separation and Enrichment of Lectin from Zihua Snap-Bean (Phaseolus vulgaris) Seeds by PEG 600-Ammonium Sulfate Aqueous Two-Phase System

A fast and efficient method based on a polyethylene glycol (PEG) 600/(NH₄)₂SO₄ aqueous two-phase system for extracting lectin from Zihua snap-bean (Phaseolus vulgaris) seeds was established. According to a Box-Behnken design (BBD), involving four factors at three levels each subjected to analysis of variance (ANOVA) and response surface analysis, the protein recovery and the purification factor of lectin in the top phase were used as the response values of the variance analysis to acquire the multivariate quadratic regression model. SDS-PAGE electrophoresis and the hemagglutination test were used to detect the distribution of lectin in the aqueous two-phase system (ATPS). The obtained data indicated that lectin was preferentially partitioned into the PEG-rich phase, and the ATPS, composed of 15% (NH₄)₂SO₄ (w/w), 18% PEG 600 (w/w), 0.4 g/5 g NaCl and 1 mL crude extract, showed good selectivity for lectin when the pH value was 7.5. Under the optimal conditions, most of the lectin was assigned to the top phase in the ATPS, and the hemagglutination activity of the purified lectin in the top phase was 3.08 times that of the crude extract. Consequently, the PEG 600/(NH₄)₂SO₄ aqueous two-phase system was an effective method for separating and enriching lectin directly from the crude extract of Zihua snap-bean seeds.

Partitioning in aqueous two-phase systems: Analysis of strengths, weaknesses, opportunities and threats

For half a century aqueous two-phase systems (ATPSs) have been applied for the extraction and purification of biomolecules. In spite of their simplicity, selectivity, and relatively low cost they have not been significantly employed for industrial scale bioprocessing. Recently their ability to be readily scaled and interface easily in single-use, flexible biomanufacturing has led to industrial re-evaluation of ATPSs. The purpose of this review is to perform a SWOT analysis that includes a discussion of: (i) strengths of ATPS partitioning as an effective and simple platform for biomolecule purification; (ii) weaknesses of ATPS partitioning in regard to intrinsic problems and possible solutions; (iii) opportunities related to biotechnological challenges that ATPS partitioning may solve; and (iv) threats related to alternative techniques that may compete with ATPS in performance, economic benefits, scale up and reliability. This approach provides insight into the current status of ATPS as a bioprocessing technique and it can be concluded that most of the perceived weakness towards industrial implementation have now been largely overcome, thus paving the way for opportunities in fermentation feed clarification, integration in multi-stage operations and in single-step purification processes.