Among 22 species of microorganisms isolated from phenol-containing wastewaters, Candida parapsilopsis was found to be capable of growth on a medium with 1 g/L phenol. Kinetic parameters of phenol biodegradation in a batch reactor were determined by measuring biomass growth rates and phenol concentration as a function of fermentation time. The Haldane equation described cell growth adequately, with kinetic constants mumax = 0.174/h, KS = 11.2 mg/L and Ki = 298 mg/L.

• MeSH
• biodegradace MeSH
• biomasa MeSH
• Candida cytologie   růst a vývoj   izolace a purifikace   metabolismus   MeSH
• chemické látky znečišťující vodu metabolismus   MeSH
• čištění vody metody   MeSH
• fenol metabolismus   MeSH
• kinetika MeSH
• kultivační média chemie   MeSH
• mikrobiologie vody * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chemické látky znečišťující vodu MeSH
• fenol MeSH
• kultivační média MeSH

Several aerobic metabolic pathways for the degradation of benzene, toluene, ethylbenzene and xylene (BTEX), which are provided by two enzymic systems (dioxygenases and monooxygenases), have been identified. The monooxygenase attacks methyl or ethyl substituents of the aromatic ring, which are subsequently transformed by several oxidations to corresponding substituted pyrocatechols or phenylglyoxal, respectively. Alternatively, one oxygen atom may be first incorporated into aromatic ring while the second atom of the oxygen molecule is used for oxidation of either aromatic ring or a methyl group to corresponding pyrocatechols or protocatechuic acid, respectively. The dioxygenase attacks aromatic ring with the formation of 2-hydroxy-substituted compounds. Intermediates of the "upper" pathway are then mineralized by either ortho- or meta-ring cleavage ("lower" pathway). BTEX are relatively water-soluble and therefore they are often mineralized by indigenous microflora. Therefore, natural attenuation may be considered as a suitable way for the clean-up of BTEX contaminants from gasoline-contaminated soil and groundwater.

• MeSH
• aerobní bakterie enzymologie   metabolismus   MeSH
• benzen metabolismus   MeSH
• benzenové deriváty metabolismus   MeSH
• biodegradace MeSH
• toluen metabolismus   MeSH
• uhlovodíky chemie   metabolismus   MeSH
• xyleny metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• benzen MeSH
• benzenové deriváty MeSH
• ethylbenzene MeSH Prohlížeč
• toluen MeSH
• uhlovodíky MeSH
• xyleny MeSH

The kinetics of phenol degradation was estimated in a fed-batch reactor system. Effects of oxygen and nutrient excess or limitation as well as the presence of several essential ions on the phenol- and oxygen-specific uptake rates achieved simultaneously in a bioreactor were shown. Candida tropicalis was grown on phenol as the only carbon and energy source. Applying the best fit of polynomial function, the maximum specific uptake rates of phenol and oxygen, the critical concentrations of phenol, the half-saturation constants and inhibition constants were determined. Linear relationship between specific phenol uptake rate and the exogenous respiration rate was found regardless of the kind and presence of essential nutrients. At oxygen limitation both the phenol uptake rate and the cell affinity to phenol decreased more strongly compared with those under nutrient limitation. Oxygen in excess resulted in a significant increase of cell tolerance toward phenol. The presence of essential nutrients increased the specific phenol degradation rate and led to complete phenol oxidation.

• MeSH
• biodegradace MeSH
• bioreaktory MeSH
• Candida tropicalis metabolismus   MeSH
• chemické látky znečišťující vodu metabolismus   MeSH
• fenol metabolismus   MeSH
• kinetika MeSH
• kyslík metabolismus   MeSH
• metoda nejmenších čtverců MeSH
• oxidace-redukce MeSH
• spotřeba kyslíku MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chemické látky znečišťující vodu MeSH
• fenol MeSH
• kyslík MeSH

Laboratory-scale biofilters packed with a mixture of peat, bark and wood were used for xylene and toluene removal from waste air. Two kinds of peat, which differed in the resulting pH of the leachate, were chosen for degradation of the pollutants by a mixed culture. Using peat with the lower pH value, the feasibility of single and multiple pollutant loading during the start-up period and augmentation with Pseudomonas putida strains were characterized. The lower pH value of the bed resulted in higher efficiency of toluene degradation from the mixture of pollutants. At higher pH values better degradation of both pollutants was achieved. Regarding the manner of loading during the start-up period, the best results were obtained using toluene as a single pollutant in the initial phase of operation. Pseudomonas strains demonstrated a high ability to degrade both pollutants; more efficient degradation for xylene than for toluene was observed at high loading rates.

• MeSH
• biodegradace MeSH
• koncentrace vodíkových iontů MeSH
• látky znečišťující vzduch metabolismus   MeSH
• Pseudomonas putida metabolismus   MeSH
• půda MeSH
• toluen metabolismus   MeSH
• xyleny metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• látky znečišťující vzduch MeSH
• půda MeSH
• toluen MeSH
• xyleny MeSH