Polyethylene glycol improves phenol removal by immobilized turnip peroxidase.
Purified peroxidase from turnip (Brassica napus L. var. esculenta D.C.) was immobilized by entrapment in spheres of calcium alginate and by covalent binding to Affi-Gel 10. Both immobilized Turnip peroxidase (TP) preparations were assayed for the detoxification of a synthetic phenolic solution and a real wastewater effluent from a local paints factory. The effectiveness of phenolic compounds (PC's) removal by oxidative polymerization was evaluated using batch and recycling processes, and in the presence and in the absence of polyethylene glycol (PEG). The presence of PEG enhances the operative TP stability. In addition, reaction times were reduced from 3h to 10 min, and more effective phenol removals were achieved when PEG was added. TP was able to perform 15 reaction cycles with a real industrial effluent showing PC's removals >90% PC's during the first 10 reaction cycles. High PC's removal efficiencies (>95%) were obtained using both immobilized preparations at PC's concentrations <1.2mM. Higher PC's concentrations decreased the removal efficiency to 90% with both preparations after the first reaction cycle, probably due to substrate inhibition. On the other hand, immobilized TP showed increased thermal stability when compared with free TP. A large-scale enzymatic process for industrial effluent treatment is expected to be developed with immobilized TP that could be stable enough to make the process economically feasible.
Quintanilla-Guerrero
F
F
Departamento de Investigación y Posgrado en Alimentos, Universidad Autónoma de Querétaro, C.U. Cerro de las Campanas, Qro 76010, Mexico.
Duarte-Vázquez
M A
MA
García-Almendarez
B E
BE
Tinoco
R
R
Vazquez-Duhalt
R
R
Regalado
C
C
D000464:Alginates / Q000378:metabolism; D052160:Benzothiazoles / Q000378:metabolism; D001673:Biodegradation, Environmental / Q000187:drug effects; D029688:Brassica napus / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability / Q000187:drug effects; D004800:Enzymes, Immobilized / Q000302:isolation & purification / Q000378:metabolism*; D020723:Glucuronic Acid / Q000378:metabolism; D006603:Hexuronic Acids / Q000378:metabolism; D007220:Industrial Waste; D007700:Kinetics; D010084:Oxidation-Reduction / Q000187:drug effects; D009195:Peroxidase / Q000302:isolation & purification / Q000378:metabolism*; D019800:Phenol / Q000302:isolation & purification*; D011092:Polyethylene Glycols / Q000494:pharmacology*; D013451:Sulfonic Acids / Q000378:metabolism; D013696:Temperature; D013816:Thermodynamics
D000464:Alginates; D052160:Benzothiazoles; D004800:Enzymes, Immobilized; D006603:Hexuronic Acids; D007220:Industrial Waste; D013451:Sulfonic Acids; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; D019800:Phenol; D011092:Polyethylene Glycols; D020723:Glucuronic Acid; D009195:Peroxidase