ABSTRACT
Chloroperoxidase (CPO) from Caldariomyces fumago catalyses the oxidation of several chlorinated phenols (CP) commonly found in industrial waste waters in the presence of hydrogen peroxide. This study compares the direct addition of hydrogen peroxide (DA) with its continuous electrogeneration (EG) during the enzymatic oxidation of CP. Reaction mixtures were studied containing chemically modified CPO, hydrogen peroxide and the phenolic substrates: phenol (P), 4-chlorophenol (4-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP) and pentachlorophenol (PCP), in 100 mM sodium-potassium phosphate buffer pH 6.0, at 25ºC. Results were compared in terms of residual phenol concentration (oxidation efficiency), precipitate formation (removal) and residual enzyme activity (stability). With the electrochemical system evaluated at -620 mVSCE, and continuous aeration the maximum H2O2 concentration of 1.2 mM was obtained. Under this conditions and after 4 hrs using EG, no phenol or 4-CP were detected, and 97 percent, 93 percent and 88 percent of 2,4-DCP, 2,4,6-TCP and PCP were degraded, respectively. The use of EG improves enzyme half-life time in comparison to the results obtained by DA.
ABSTRACT
Se encontró que extractos crudos provenientes del cultivo de Aspergillus niger cepa AN 166 poseen alta actividad de fructosiltransferasa. Se implementó un ensayo enzimático para evaluar las actividades de hidrolisis y transferencia observadas para la enzima que produce este microorganismo. Fueron encontradas actividades hidrolítica y de transferencia intra y extracelulares. Se encontro una mayor actividad extracelular de transferencia que la correspondiente encontrada para la fracción intracelular. La caracterización realizada permitirá posteriores estudios a nivel molecular de la o las enzimas que presentaron la actividad evaluada en esta cepa