PEG/NaPA aqueous two-phase systems for the purification of proteases expressed by Penicillium restrictum from Brazilian Savanna

Extraction and purification of Aspergillus tamarii β-fructofuranosidase with transfructosylating activity using aqueous biphasic systems (PEG/phosphate) and magnetic field

β-fructofuranosidases (FFases) are enzymes involved in sucrose hydrolysis and fructo-oligosaccharides' production which are of great interest for the food industry. FFase from Aspergillus tamarii URM4634 was extracted using PEG/Phosphate Aqueous Biphasic Systems (ABS), and the impact of magnetic field on the extraction behavior was evaluated. A 2⁴-full experimental design was employed to study the influence of molar mass of PEG, concentrations of PEG and phosphate and pH on the selected response variables, i.e., partition coefficient (K), purification factor (PF), activity yield (Y) and selectivity (S). The influence of magnetic field during partition and NaCl concentration on the same responses was also studied. The best results of FFase extraction without magnetic field (K = 0.50, PF = 4.05, Y = 72.66% and S = 0.06) were observed at pH 8.0 using 12.5% (w/w) PEG 400 and 25% (w/w) NaH₂PO₄/K₂HPO₄. Application of the magnetic field allowed improving the performance, with the best results being obtained at the longest distance between magnets (lowest magnetic field) and absence of NaCl (K = 0.93, PF = 4.22, Y = 83.79% and S = 0.09). The outcomes obtained demonstrate that ABS combination with low intensity magnetic field can be used as an efficient FFase pre-purification method.

Extractive fermentation for process integration of protease production by Aspergillus tamarii Kita UCP1279 and purification by PEG-Citrate Aqueous Two-Phase System

The present study evaluated the influence of the variables polyethylene glycol (PEG) molar mass, pH, PEG concentration and sodium citrate concentration in the integrated production of the protease from Aspergillus tamarii Kita UCP1279 by extractive fermentation, obtaining as a response the partition coefficient (K), activity yield (Y) and concentration factor (CF). The enzyme preferably partitioned to the top phase and obtained in the system formed by variables M_PEG = 400 g mol^-1, C_PEG = 20% (w w^-1), and C_CIT = 20% (w w^-1) and pH 6, in this condition were obtained CF = 1.90 and Y = 79.90%. The protease showed stability at a temperature of 60 °C for 180 min, with optimum temperature 40 °C and pH 8.0. For the ions and inhibitors effects, the protease activity increased when exposed to Fe²⁺, Ca²⁺ and Zn^{2 +} and inhibited by EDTA, being classified as metalloprotease. The kinetic parameters K_m (35.63 mg mL^-1) and V_max (1.205 mg mL^-1min^-1) were also estimated. Thus, the protease showed desirable characteristics that enable future industrial applications, especially, for beer industry.

Separation of phenolic acids by centrifugal partition chromatography

Phenolic acids are ubiquitous biomolecules exhibiting a wide range of physiological properties, with application in the pharmaceutical and nutraceutical fields. In this work, aqueous biphasic systems (ABS) formed by polyethylene glycol and sodium polyacrylate, and inorganic salts or ionic liquids as electrolytes, were applied to the purification of caffeic, ferulic and protocatechuic acids, followed by the use of centrifugal partition chromatography (CPC) to reinforce the fractionation process scale-up. In single-step experiments in ABS, high selectivities (S_FA/CA = 12.09; S_CA/PA = 6.32; S_FA/PA = 1.91) and adequate partition coefficients (K_CA = 2.78 ± 0.20; K_PA = 0.44 ± 0.04; K_FA = 0.23 ± 0.01) were achieved using ABS formed by sodium chloride as electrolyte. This system was further applied in CPC, allowing an efficient separation of the three phenolic acids after the optimization of the equipment operational conditions, while demonstrating the potential of polymer-based ABS to be used in liquid-liquid chromatography. Finally, the recovery of the phenolic acids (≥ 65%) with high purity from the ABS phases was demonstrated, followed by the reuse of the phase-forming components.

Purification of bacterial inulinase in aqueous two-phase systems

In this study, extracellular inulinase from Bacillus sp. 11/3 was partially purified and concentrated using aqueous two-phase system (ATPS). Two different phase forming salts and four types of polyethylene glycol (PEG) were used. Binodal curves and tie-length lines (TLLs) for eight ATPS were developed. For inulinase purification, concentrations of PEG and salt according to binodal curves (between 17 and 26%) were chosen. All ATPSs for inulinase purification were characterized. An ATPS consisted of 26% PEG1000 and 26% MgSO₄ was found to be the most suitable for inulinase purification. This ATPS has 28.47% TLL, 1.03 of volume ratio, purification factor of 4.65 fold and recovery yield of 66.17%. On the SDS-PAGE electrophoresis two protein bands with molecular weight of around 24 and 56 kDa were observed. The partially purified enzymes had optimal activity at pH 8.0 and 6.5, optimal temperature at 30 and 70°C and kinetic parameters K_m = 26.32 mmol and V_max = 526 mmol/min.