Toxicity and kinetic parameters of the aerobic biodegradation of the phenol and alkylphenols by a mixed culture.
A mixed culture aerobically metabolized phenol, cresol isomers (o-,m-,p-), 2-ethylphenol and xylenol isomers (2,5-DMP and 3,4-DMP) as the sole carbon and energy source. This culture had a high tolerance towards phenol with values of maximum degradation rate (Vmax) of 47 microM phenol mg-1 protein h-1 and inhibition substrate constant (Ki) of 10 mM. These kinetic parameters were considerably diminished and the toxicity increased with the alkylphenols. For example with 2,5-xylenol, Vmax and Ki values of 0.8 microM 2,5-xylenol mg-1 protein h-1 and 1.3 mM, respectively, were obtained. The cresols were 5-fold more toxic than phenol, whereas 2-ethylphenol and 3,4-xylenol were 11-fold more toxic, and 2,5-xylenol was 34-fold more toxic than phenol.
Acuña-Argüelles
M E
ME
Programa de Biotecnología, Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas 152 Nte, C.P. 07730, México D.F., México. meacuna@imp.mx
Olguin-Lora
P
P
Razo-Flores
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E
D000332:Aerobiosis; D001673:Biodegradation, Environmental / Q000187:drug effects; D003408:Cresols / Q000378:metabolism / Q000633:toxicity; D007218:Industrial Microbiology / Q000379:methods*; D007700:Kinetics; D010636:Phenols / Q000378:metabolism* / Q000633:toxicity; D012988:Soil Microbiology; D018675:Toxicity Tests; D014992:Xylenes / Q000378:metabolism / Q000633:toxicity
D003408:Cresols; D010636:Phenols; D014992:Xylenes; C016834:3,5-xylenol; C048893:2,5-xylenol