Single step purification of bromelain from Ananas comosus pulp using a polymer/salt aqueous biphasic system

Bromelain is an important industrial proteolytic enzyme due to the wide application in food, cosmetic and therapeutic industries. There is a great demand in developing a cost-efficient method to recover bromelain from plant sources. Low interfacial tension and biocompatible aqueous biphasic system (ABS) is widely applied in various separation processes of bioproducts. Thus, recovery of bromelain from Ananas comosus (pineapple) pulp using polymer/salt ABS was attempted in this study. The ABS operating factors including polyethylene glycol (PEG) molecular weight, phase composition, pH, centrifugal force and additional of neutral salt were studied. The optimal condition for ABS recovery of bromelain from crude extract was achieved with ABS consisting of 17% (w/w) PEG 4000 and 14% (w/w) phosphate salt; centrifugal force of 6000 × g; pH of 8.0 and at 25°C. Bromelain exhibited a high specific activity (SA) of 2.7 U and purification factor (PF) of 16.3 in the top phase of PEG 4000/phosphate ABS with a yield (YT) of 55.6%. The findings demonstrated that ABS is a potential one-step operation in replacement to the existing methods in recovery of bromelain from plant sources.