Effect of some inorganic salts on the partitioning of pectinase of Polyporus squamosus in polyethylene glycol/crude dextran aqueous two-phase system

The effect of two inorganic salts, ammonium sulphate and potassium dihydrogenphosphate, on the partitioning of pectinases produced by Polyporus squamosus in polyethylene glycol/crude dextran aqueous two-phase system is reported. Presence of both salts at different concentration did not affect partition of biomass, so fungal growth was occurring exclusively in the bottom phase. At 30 mmol (NH₄)₂SO₄/l in two-phase medium, the partition coefficient of endo-pectinase was 3.9, and it was 80% improved in comparison to that obtained at twofold lower salt concentration. On the other hand, higher (NH₄)₂SO₄ concentration increased total exo-pectinase activity produced, but did not affect substantially its partition parameters. Increasing phosphate concentration stimulated partition of both enzymes to the top phase: at 0.2 mol KH₂PO₄/l the partition coefficient for exo-pectinase was about 20% higher than at 0.1 mol/l, and one-sided partition of endo-pectinase was accomplished, and consequently maximal top phase yield.