Studies on Bromelain Precipitation by Ethanol, Poly(ethylene Glycol) and Ammonium Sulphate

Brazil produces over than 58.000 hectares of pineapple, beeing the world leader in pineapple production. Aiming the recovery of agriculture residues (stalk and leaves), and fruit processing residues (stem and bark), several researches have been carried out for the recovery of pineapple’s enzymes, such as the bromelain. These enzymes performs important role in proteolytic modulation at cellular matrix, in numerous physiologic process, including tissue morphogenesis, tissue repair, angiogenesis and tissue modulation, decreasing bruises, swelling, pain and healing time. This work aims the recovery on bromelain from pineapple stem, bark and leaves. Aqueous extract of bromelain was prepared through stem, bark and leaves processing in a common blender. Precipitation studies were performed under refrigeration (4 °C). Poly(ethylene glycol) precipitations were carried out in a single step, in various concentrations. Ethanol and ammonium sulphate precipitations were carried out stepwise, where several concentrations of ethanol and ammonium sulphate were added to perform a fractional precipitation. Results showed that bromelain was not precipitated by poly(ethylene glycol) at all. However, bromelain was recovered with 30-70% ethanol fraction, in which were achieved a purification factor of 2.07 fold, and yielded over than 98% of enzymatic activity. Precipitation with ammonium sulphate showed that bromelain was recovered at 20-40 saturation fractions, yielding up to 44% of protein recovery, and a purification factor of 4.4 fold. Although the ethanol precipitation had achieved a lower purification factor, it seems to be more suitable for bromelain recovery, based on process time and local ethanol price, since Brazil is the largest ethanol producer worldwide.