99A-8 |
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C. Regalado, F. QUINTANILLA, and B. E. García-Almendárez. Depto. Investigación y Posgrado en Alimentos/Biotechnology Group, Universidad Autónoma de Querétaro, Facultad de Química, Centro Universitario, Cerro de las Campanas, Querétaro, Qro., 76010, Mexico The need to have contaminant free foods is a growing demand, since the resources exist but, particularly, the water as eating vehicle may be contaminated by phenolic compounds, among others. Immobilized turnip peroxidase can be used to remove phenol by oxidative polymerization; being immobilized, it can be used repeatedly. Our objective consisted of immobilizing peroxidase from a crude extract of turnip (Brassica napus L.var. esculenta D.C.) to expand the range of pH and temperature for efficient phenol removal from a synthetic wastewater containing 0.5 mM of phenol, in a process which can be conducted repeatedly. Immobilization was carried out using an entrapment method with alginic acid fed dropwise into a CaCl 2 solution. Alternatively, a covalent immobilization using epoxi-amino-sepabeads (Resindion srl) was used. Alginate beads removed more than 90% of phenol after 3 hours of reaction. Nevertheless the remnant enzymatic activity diminished to 32% of the initial activity. The larger the volume of the beads containing immobilized turnip peroxidase, the longer took the newly formed polymer to get out of the beads. This was solved with the formation of films that increased the surface contact between the immobilized enzyme and the phenol in solution. With epoxi-amino-sepabeads the remnant activity was higher than 58% but its physical state did not permit to employ it again. Alginate films are under development for its repeated use. Immobilization is a simple and economic process, which may be employed for removal of phenol contaminated wastewaters. The turnip roots, which are readily available in Mexico, are a good source of peroxidase, and because of their kinetic and biochemical properties have a high potential as an economic alternative to horseradish peroxidase, and to favor its massive employment.
Session 99A, Biotechnology: General
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