Application of aqueous biphasic systems as strategy to purify tannase from Aspergillus tamarii URM 7115.

The aims of the current study are to assess the influence of polyethylene glycol (PEG) concentration, molar mass, pH, and citrate concentrations on aqueous biphasic systems based on 2 factorial designs, as well as to check their capacity to purify tannase secreted by Aspergillus tamarii URM 7115. Tannase was produced through submerged fermentation at 26°C for 67 h in Czapeck-Dox modified broth and added with yeast extract and tannic acid. The factorial design was followed to assess the influence of PEG molar mass (M 600; 4,000 and 8,000 g/ mol), and PEG (C 20.0; 22.0 and 24.0% w/w) and citrate concentrations (C 15.0, 17.5, and 20.0%, w/w), as well as of pH (6.0, 7.0, and 8.0) on the response variables; moreover, partition coefficient (K), yield (Y), and purification factor (PF) were analyzed. The most suitable parameters to purify tannase secreted by A. tamarii URM 7115 through a biphasic system were 600 (g/mol) M, 24% (w/w) C, 15% (w/w) C at pH 6.0 and they resulted in 6.33 enzyme partition, 131.25% yield, 19.80 purification factor and 195.08 selectivity. Tannase secreted by A. tamarii URM 7115 purified through aqueous biphasic systems composed of PEG/citrate can be used for industrial purposes, since it presents suitable purification factor and yield.