Purification of polygalacturonases produced by Aspergillus niger using an aqueous two-phase system

• Published in: Fluid phase equilibria 2014-06, Vol.371, p.125-130
• Main Authors: Maciel, Marília de H.C., Ottoni, Cristiane A., Herculano, Polyanna N., Porto, Tatiana S., Porto, Ana L.F., Santos, Cledir, Lima, Nelson, Moreira, Keila A., Souza-Motta, Cristina
• Format: Article
• Language: English
• Subjects: Aspergillus niger; Partition; PEG/phosphate ATPS; Polygalacturonases; Purification factor; Science & Technology
• ISSN: 0378-3812; 1879-0224; 0378-3812
• DOI: 10.1016/j.fluid.2014.03.018

•ATPS was used by partitioning and purification of PG.•PEG molar mass, phase concentrations and pH were evaluated on purification.•PEG molar mass and phosphate concentration have prominent effect on the response variables.•ATPS provides an efficient and attractive method for purifying the PG. The partitioning and purification of polygalacturonases (PG) produced by Aspergillus niger URM 5162 were investigated in aqueous two-phase systems (ATPS), formed by polyethylene glycol and phosphate salts (PEG/phosphate). To evaluate the effect of the 4 independent variables – molar mass of polyethylene glycol (PEG) (400–8000g/mol – MPEG), PEG concentration (12.5–17.5%, w/w – CPEG), phosphate concentration (15–25%, w/w, CPHOS) and pH (6.0–8.0) – on the 4 response variables: partition coefficient (K), activity yield (Y), purification factor (PF) and selectivity (S), a factorial design (24) was used. The endo-polygalacturonases (endo-PG) and exo-polygalacturonase (exo-PG) were preferentially partitioned in the top phase. For endo- and exo-PG, the highest values for the response variables K (1.23 and 2.40), Y (74.04% and 17.97%), PF (8.18 and 1.98) and S (24.68 and 48.07), respectively, were obtained for a CPEG of 12.5% (w/w), MPEG of 8000g/mol, and CPHOS of 25% (w/w) at pH 6.0. These conditions were considered the most suitable for the purification of PG produced by A. niger URM 5162. Furthermore, the most important independent variables for endo- and exo-PG were CPHOS and MPEG, respectively. All independent variables studied and their interactions significantly influenced the response variables. According to these results, the PEG/phosphate system is a useful cost-effective alternative for purification of PG produced by A. niger URM 5162.