One-step procedure for peroxidase concentration, dye separation, and color removal by aqueous two-phase system.

The aim of our study is to develop a one-step procedure to remove and degrade dyes from wastewater using a low-cost and efficient system based on aqueous two-phase system (ATPS), a well-known technique used to concentrate and recover enzymes. We investigated the catalytic proprieties of rice bran peroxidase (RBP) and found that this homemade enzyme can remain bound to its substrate for up to 5 days in controlled environments, without denaturing and while maintaining stable oxidation reduction potential (ORP) and pH. This biomolecule showed affinity for the ATPS technique prepared with polyethylene glycol and salt, which improved the relative activity up to 170%. The red dye separation in ATPS top phase was achieved in 3 min, in the RBP presence, with 100% of efficiency, and color removal of 87% was obtained in 24 h of enzymatic reaction. The process has promise to be scaled up to 10-fold and to reuse the reagents from the bottom phase of the ATPS.