Purification of bromelain from wet Ananus comosus latex by extraction in aqueous two-phase system was studied and compared with the traditional procedure involving a two-step salt precipitation. The bromelain obtained by the latter method was usually contaminated with other proteins, and its purity was dependent on the initial protein concentration in the material used for processing. Highly pure bromelain was obtained in a much shorter processing time directly from the stem than the fruit portion with the use of an aqueous two-phase system consisting of 8% (w/w) polyethylene glycol and 15 % (w/w) ammonium sulfate. The purified product obtained from stem and fruit were further characterized by SDS-PAGE and their molecular weights were determined as 23 KDa (Biphasic) and 19 KDa (Salt Precipitation) for the fruit sample. Similarly, 28 KDa (Biphasic) and 20 KDa (Salt precipitation) for the Stem sample. From this investigation, it is confirmed that the Bromelain, molecular size is found to be high in the Biphasic system.
