Bromelain recovery from pineapple subproducts by ultrafiltration and aqueous biphasic systems: processes comparison and integration

The purification and concentration of bromelain from pineapple ( Ananas comosus ) subproducts can add value to an agro-industrial residue, which constitutes an environmental problem. The use of an aqueous biphasic system, ABS, ultrafiltration, UF, and an integrated process were investigated, aiming at the recovery of bromelain from pineapple peel, crown, and stem residues. Single process evaluation (ABS or UF) was conducted by means of a fractionated two-level factorial design. The aqueous biphasic system was investigated by using PEG (6 kDa, concentration ranging from 20 to 30% w/w) and potassium phosphate (2.5 mol/L) phases. Ultrafiltration tests were conducted with two different membranes in series (100 and 3 kDa). Process integration, PI, was evaluated at the best experimental condition of each individual process. ABS showed total protein recovery of 85.48% using 30% w/w of PEG in pH 7.5. UF revealed total protein recovery of 89.8% in pH 6.5, a similar value found for PI (89%). Regarding bromelain recovery, UF was the best route (93.2%), compared to ABS (18.5%) and PI (14.1%). Therefore, the choice of the proper route will depend on the final application of the product.