Salting out Tergitol 15S-based surfactants for extremolipases separation

Abstract

In the present work, the ability of different sodium-based salts like Na2CO3, Na2HPO4, Na2SO4 and Na2SO3 to salt out aqueous solutions of two biodegradable non-ionic surfactants (Tergitol 15S7 and Tergitol 15S9) has been demonstrated. We have empirically characterized the immiscibility regions and models like Merchuk and Othmer-Tobias equations were employed for binodal and tie-line data, respectively. The effect of phase forming components on the lipolytic activity of two in-house extremolipases (from Thermus thermophilus HB27 and Halomonas sp-LM1C) was studied prior to approach the separation. It was concluded that ions bearing the lowest capacity to establish hydrogen bonds with water molecules like sulphate led to greater activation effect. Then, the ability of the proposed systems to extract both lipases was compared with a commercial one, lipase B from Candida antarctica, and it was concluded that 50% of activity decay was avoided when in-house extreme enzymes were employed.