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.

Advanced oxidation processes applied for color removal of textile effluent using a home-made peroxidase from rice bran.

Enzymes are becoming tools in industrial processes because of several advantages, including activity in mild environmental conditions, and high specificity. Peroxidase, for one, stably oxidizes several substrates. The present study aimed to develop advanced oxidation processes (AOP), using non-commercial rice bran peroxidase to remove color and toxicity of synthetic textile wastewater. Using a microwave and shaker system, we obtained 38.9% and 100% of effluent color removal after peroxidase treatment, respectively. In addition, the shaker system decants residual dye particles through filtration, providing the textile industry with an economical and environmentally viable alternative to effluent treatment. In toxicity tests results, both treatment systems damaged the used genetic material. This damage occurs because of industrial discharge of wastewater into water bodies; effluent dilution reduced this damage. The data suggest that peroxidase as a textile effluent treatment has potential uses in industrial processes, because rice bran peroxidase has demonstrated affinity with dyes.