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
• Biodegradation, Environmental MeSH
• Biomass MeSH
• Candida cytology   growth & development   isolation & purification   metabolism   MeSH
• Water Pollutants, Chemical metabolism   MeSH
• Water Purification methods   MeSH
• Phenol metabolism   MeSH
• Kinetics MeSH
• Culture Media chemistry   MeSH
• Water Microbiology * MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Water Pollutants, Chemical MeSH
• Phenol MeSH
• Culture Media 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
• Bacteria, Aerobic enzymology   metabolism   MeSH
• Benzene metabolism   MeSH
• Benzene Derivatives metabolism   MeSH
• Biodegradation, Environmental MeSH
• Toluene metabolism   MeSH
• Hydrocarbons chemistry   metabolism   MeSH
• Xylenes metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Names of Substances
• Benzene MeSH
• Benzene Derivatives MeSH
• ethylbenzene MeSH Browser
• Toluene MeSH
• Hydrocarbons MeSH
• Xylenes 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
• Biodegradation, Environmental MeSH
• Bioreactors MeSH
• Candida tropicalis metabolism   MeSH
• Water Pollutants, Chemical metabolism   MeSH
• Phenol metabolism   MeSH
• Kinetics MeSH
• Oxygen metabolism   MeSH
• Least-Squares Analysis MeSH
• Oxidation-Reduction MeSH
• Oxygen Consumption MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Water Pollutants, Chemical MeSH
• Phenol MeSH
• Oxygen MeSH

Styrene vapors from contaminated air were eliminated using long-term adapted mixed microbial culture inoculated on four perlite packed biofilters (serial arrangement, up-flow configuration). During start-up the inlet concentration of styrene rose from 175 to 1300 mg/m3 of total carbon. The total actual residence time in the four biofilters was 24 s. Styrene was successfully degraded by the microbial population in the biofilter. An average of 66% of eliminated styrene was transformed to CO2. The removal efficiency of the pollutant was, after 18 d of start-up, nearly 85% at an organic load of 170 g/m3 per h. The concentration profiles along the bed height were linear for various pollutant inlet concentrations. The total amount of microorganisms in analyzed biomass from the biofilters was about 10(9) per gram of dry packing mass. The moisture content was around 80% in all biofilters.

• MeSH
• Biodegradation, Environmental MeSH
• Air Pollutants metabolism   MeSH
• Carbon Dioxide metabolism   MeSH
• Soil Microbiology MeSH
• Styrene metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Air Pollutants MeSH
• Carbon Dioxide MeSH
• Styrene MeSH