Partition of lectin from Canavalia grandiflora Benth in aqueous two-phase systems using factorial design

Influence of different PEG/salt aqueous two-phase system on the extraction of 2,3-butanediol

The production of 2,3-butanediol (2,3-BDO), a dialcohol of great interest for the food, chemical, and pharmaceutical industry, through the fermentation of biomass, is a sustainable process strategic position for countries with abundant biomass generated by the agribusiness. However, the downstream process of 2,3-BDO is onerous due to the complexity of fermentation broth and the physical-chemical characteristics of the 2,3-BDO. This study investigated the feasibility of 2,3-BDO extraction from model aqueous solutions using aqueous two-phase systems (ATPS). A central composite rotational design (CCRD) was employed to evaluate different ATPS compositions and the influences on the 2,3-BDO recovery and partition coefficient. The polyethylene glycol (PEG) and different concentrations of sodium citrate, ammonium sulfate, and potassium phosphate were investigated. The concentration of salt and PEG in the ATPS was identified as the most significant factors influencing the recovery and partition coefficient of 2,3-BDO. The recovery of 2,3-BDO reached 94.5% and was obtained when the system was composed of 36.22% (w/w) of PEG 4000 and 4.47% (w/w) of potassium phosphate. The results indicate that ATPS based on PEG-salt has a high potential for industrial application, using mild conditions and a simple process for recovering and purifying the 2,3-BDO produced from microbiological synthesis.

Purification of a lectin from Cratylia mollis crude extract seed by a single step PEG/phosphate aqueous two-phase system

The partitioning and purification of lectins from the crude extract of Cratylia mollis seeds (Cramoll 1,4) was investigated in aqueous two-phase systems (ATPS). A factorial design model (2⁴) was used to evaluate the influence of polyethylene glycol (PEG) molar mass (1500-8000 g/mol), PEG concentration (12.5-17.5% w/w), phosphate (10-15% w/w) concentration, and pH (6-8) on the differential partitioning, purification factor, and yield of the lectin. Polymer and salt concentration were the most important variables affecting partition of lectin and used to find optimum purification factor by experimental Box-Behnken design together with the response surface methodology (RSM). ATPS showed best conditions composed by 13.9% PEG1500, 15.3% phosphate buffer at pH 6, which ensured purification factor of 4.70. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed a single band of protein with 26.1 kDa. Furthermore, results demonstrated a thermostable lectin presenting activity until 60 °C and lost hemagglutinating activity at 80 °C. According to the obtained data it can be inferred that the ATPS optimization using RSM approach can be applied for recovery and purification of lectins.

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.

Aqueous two phase partitioning of Pisum sativum lectin in PEG/citrate salt system

Pisum sativum lectin (Psl) is a metalloprotein which is in the center of research interest because of its HIV-1 reverse transcriptase inhibitory activity and mitogenic activity. The application of this lectin in various fields demands the economically feasible and scalable purification strategy other than affinity chromatography. The suitability of aqueous two phase system (ATPS) composed of poly ethylene glycol (PEG) with different salts (sodium citrate, potassium citrate, and ammonium citrate) was evaluated for better partitioning of Psl. The significant factors such as molar mass and concentration of PEG, type and concentration of salts, the effect of tie line length (TLL), ionic strength, and pH were studied to select a suitable system for better partitioning of Psl. ATPS comprising of 18% PEG 6000, 16% sodium citrate, 1% NaCl at the operating condition of pH 8, 40.23% of TLL, and the volume ratio of 1.32 was found to be the best system which gave a maximum partition coefficient and yield of 14.5% and 98.66%, respectively.

Statistical Design of Experimental and Bootstrap Neural Network Modelling Approach for Thermoseparating Aqueous Two-Phase Extraction of Polyhydroxyalkanoates

At present, polyhydroxyalkanoates (PHAs) have been considered as a promising alternative to conventional plastics due to their diverse variability in structure and rapid biodegradation. To ensure cost competitiveness in the market, thermoseparating aqueous two-phase extraction (ATPE) with the advantages of being mild and environmental-friendly was suggested as the primary isolation and purification tool for PHAs. Utilizing two-level full factorial design, this work studied the influence and interaction between four independent variables on the partitioning behavior of PHAs. Based on the experimental results, feed forward neural network (FFNN) was used to develop an empirical model of PHAs based on the ATPE thermoseparating input-output parameter. In this case, bootstrap resampling technique was used to generate more data. At the conditions of 15 wt % phosphate salt, 18 wt % ethylene oxide–propylene oxide (EOPO), and pH 10 without the addition of NaCl, the purification and recovery of PHAs achieved a highest yield of 93.9%. Overall, the statistical analysis demonstrated that the phosphate concentration and thermoseparating polymer concentration were the most significant parameters due to their individual influence and synergistic interaction between them on all the response variables. The final results of the FFNN model showed the ability of the model to seamlessly generalize the relationship between the input–output of the process.

Phaseolus vulgaris lectins: A systematic review of characteristics and health implications

Legume lectins are carbohydrate-binding proteins of non-immune origin. Significant amounts of lectins have been found in Phaseolus vulgaris beans as far back as in the last century; however, many questions about their potential biological roles still remain obscure. Studies have shown that lectins are anti-nutritional factors that can cause intestinal disorders. Owing to their ability to act as toxic allergens and hemagglutinins, the Phaseolus vulgaris lectins are of grave concern for human health and safety. Nonetheless, their potential beneficial health effects, such as anti-cancer, anti-human immunodeficiency virus (anti-HIV), anti-microbial infection, preventing mucosal atrophy, reducing type 2 diabetes and obesity, promoting nutrients absorption and targeting drugs, are of immense interest. The significance of Phaseolus vulgaris lectins in biological researches and the potential biomedical applications have placed tremendous emphasis on the development of purification strategies to obtain the protein in pure and stable forms. These purification strategies entail considerations such as effects of proteolysis, heating, gamma radiation, and high-hydrostatic-pressure that can have crucial outcomes in either eliminating or improving bioactivities of the lectins. Thus, up-to-date research findings of Phaseolus vulgaris lectins on different aspects such as anti-nutritional and health impacts, purification strategies and novel processing trends, are systematically reviewed.

Response Surface Methodology Modelling of an Aqueous Two-Phase System for Purification of Protease from Penicillium candidum (PCA 1/TT031) under Solid State Fermentation and Its Biochemical Characterization

Penicillium candidum (PCA 1/TT031) synthesizes different types of extracellular proteases. The objective of this study is to optimize polyethylene glycol (PEG)/citrate based on an aqueous two-phase system (ATPS) and Response Surface Methodology (RSM) to purify protease from Penicillium candidum (PCA 1/TT031). The effects of different PEG molecular weights (1500-10,000 g/mol), PEG concentration (9%-20%), concentrations of NaCl (0%-10%) and the citrate buffer (8%-16%) on protease were also studied. The best protease purification could be achieved under the conditions of 9.0% (w/w) PEG 8000, 5.2% NaCl, and 15.9% sodium citrate concentration, which resulted in a one-sided protease partitioning for the bottom phase with a partition coefficient of 0.2, a 6.8-fold protease purification factor, and a yield of 93%. The response surface models displayed a significant (p ≤ 0.05) response which was fit for the variables that were studied as well as a high coefficient of determination (R²). Similarly, the predicted and observed values displayed no significant (p > 0.05) differences. In addition, our enzyme characterization study revealed that Penicillium candidum (PCA 1/TT031) produced a slight neutral protease with a molecular weight between 100 and 140 kDa. The optimal activity of the purified enzyme occurred at a pH of 6.0 and at a temperature of 50 °C. The stability between different pH and temperature ranges along with the effect of chemical metal ions and inhibitors were also studied. Our results reveal that the purified enzyme could be used in the dairy industry such as in accelerated cheese ripening.

Phase system selection with fractional factorial design for purification of recombinant cyanovirin-N from a hydroponic culture medium using centrifugal partition chromatography

Centrifugal partition chromatography (CPC) with an aqueous two-phase system (ATPS) was used to purify recombinant cyanovirin-N (CV-N) from other proteins which were co-secreted into a hydroponic plant medium in a rhizosecretion process. To achieve satisfactory protein concentration, the purification was preceded by ultrafiltration performed on a 5 kDa filter. ATPS, because of their gentle nature, were selected as the phase system for CPC. A systematic phase system selection was applied. This involved studying the effect of seven parameters of ATPS: polymer type, salt type, the polymer and salt concentration, the polymer molecular weight, pH, and presence of two additional salts; NaCl and NaClO4, which all together gave 320 combinations. design of experiment (DoE) software allowed the reduction of this number to 46. Having tested partitioning of cyanovirin-N and impurities in 46 ATPS, the three best potential phase systems generated by the programme were then tested on the CPC. Out of these three, 13/13% PEG4000 sodium phosphate, pH 3.0, proved to be most effective phase system in the purification of cyanovirin-N, judged by ELISA and SDS-PAGE analysis, as it eliminated most of the impurities from the final cyanovirin-N preparation.

Development and Evaluation of Environmentally Benign Aqueous Two Phase Systems for the Recovery of Proteins from Tannery Waste Water

Aqueous two phase systems (ATPSs) containing high molecular weight polyethylene glycol, PEG (10000), and completely biodegradable citrate salts (sodium citrate, potassium citrate, and ammonium citrate) with water were developed to recover the waste water proteins from a model tannery waste water system. The variations in the phase diagram were explained on the basis of ionic radius of cations, Gibbs free energy of hydration (ΔGhydation) of cations, and effective excluded volume (EEV) of salts. The salting-out capability of the cations followed the sequence: Sodium citrate > Potassium citrate > Ammonium citrate. Setschenow-type equations were used to correlate tie-line compositions. During partitioning studies, recovery of tannery waste water proteins in PEG 10000 + Sodium citrate ATPS was found superior to other systems. It was possible to recover 95.86% of proteins from tannery waste water in the bottom phase with PEG 10000 30% (w/w) + Sodium citrate 13% (w/w) at 30°C. The partition coefficients were correlated with the salt compositions by a quadratic equation and the coefficients were calculated.