Poly(N-Isopropylacrylamide)-co-Acrylamide Hydrogels for the Controlled Release of Bromelain from Agroindustrial Residues of Ananas comosus.

Abstract

This works reports the purification of bromelain extracted from Ananas comosus industrial residues by ethanol purification, its partial characterization from the crude extract as well as the ethanol purified enzyme, and its application onto poly(N-isopropylacrylamide)-co-acrylamide hydrogels. Bromelain was recovered within the 30-70 % ethanol fraction, which achieved a purification factor of 3.12-fold, and yielded more than 90 % of its initial activity. The resulting purified bromelain contained more than 360 U · mg(-1), with a maximum working temperature of 60 °C and pH of 8.0. Poly(N-isopropylacrylamide)-co-acrylamide hydrogels presented a swelling rate of 125 %, which was capable of loading 56 % of bromelain from the solution, and was able to release up to 91 % of the retained bromelain. Ethanol precipitation is suitable for bromelain recovery and application onto poly(N-isopropylacrylamide)-co-acrylamide hydrogels based on its processing time and the applied ethanol prices.