Journal ArticleDOI
Stoichiometry and kinetics of microbial toluene degradation under denitrifying conditions.
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The inoculum originated from a mixture of sludges from sewage treatment plants with alternating nitrification and denitrification and was able to degrade toluene under anaerobic conditions in the presence of nitrate, nitrite, nitric oxide, or nitrous oxide.Abstract:
Batch experiments were carried out to investigate the stoichiometry and kinetics of microbial degradation of toluene under denitrifying conditions. The inoculum originated from a mixture of sludges from sewage treatment plants with alternating nitrification and denitrification. The culture was able to degrade toluene under anaerobic conditions in the presence of nitrate, nitrite, nitric oxide, or nitrous oxide. No degradation occurred in the absence of Noxides. The culture was also able to use oxygen, but ferric iron could not be used as an electron acceptor. In experiments with14C-labeled toluene, 34%±8% of the carbon was incorporated into the biomass, while 53%±10% was recovered as14CO2, and 6%±2% remained in the medium as nonvolatile water soluble products. The average consumption of nitrate in experiments, where all the reduced nitrate was recovered as nitrite, was 1.3±0.2 mg of nitrate-N per mg of toluene. This nitrate reduction accounted for 70% of the electrons donated during the oxidation of toluene. When nitrate was reduced to nitrogen gas, the consumption was 0.7±0.2 mg per mg of toluene, accounting for 97% of the donated electrons. Since the ammonia concentration decreased during degradation, dissimilatory reduction of nitrate to ammonia was not the reductive process. The degradation of toluene was modelled by classical Monod kinetics. The maximum specific rate of degradation, k, was estimated to be 0.71 mg toluene per mg of protein per hour, and the Monod saturation constant, K s , to be 0.2 mg toluene/l. The maximum specific growth rate, μ max , was estimated to be 0.1 per hour, and the yield coefficient, Y, was 0.14 mg protein per mg toluene.read more
Citations
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Journal ArticleDOI
Effect of temperature and dissolved oxygen on the growth kinetics of Pseudomonas putida F1 growing on benzene and toluene.
TL;DR: The oxygen half-saturation coefficient was found to be approximately 1 mg/l regardless of whether benzene or toluene was the substrate, and oxygen limited growth followed Monod saturation kinetics with the specific growth rate given as a function of the dissolved oxygen concentration.
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Biodegradation of NSO-compounds under different redox-conditions
TL;DR: In this paper, the potential of groundwater microorganisms to degrade selected heterocyclic aromatic compounds containing nitrogen, sulphur, or oxygen (NSO-compounds) under four redox-conditions over a period of 846 days was investigated.
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Biodegradation of toluene in a membrane biofilter
TL;DR: A membrane biofilter is used to biodegrade toluene in the gas phase using a porous polysulfone membrane containing water in the pore to diffused to the biofilm attached to the outside surface.
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Modelling the mineralization kinetics for low concentrations of pesticides in surface and subsurface soil
TL;DR: In this paper, a number of mathematical models were fitted to mineralization results of low concentrations of mecoprop, bentazon and ethylene thiourea (ETU) in surface (ploughed layer) and subsurface soil in different soil types and at different temperatures.
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The anoxic extractive membrane bioreactor
TL;DR: It is hypothesised that nitrate penetrates the whole biofilm, preventing the formation of inactive zones of bacteria, and is used as an electron acceptor instead of oxygen in this work.
References
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A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding
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Acetylene inhibition of nitrous oxide reduction by denitrifying bacteria.
Tadashi Yoshinari,Roger Knowles +1 more
TL;DR: The data are consistent with the view that N/ Sub 2/O is an obligatory intermediate in the reduction of NO/sub 2//sup -/ to N/ sub 2/ in all of the three organisms studied.
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Blockage by acetylene of nitrous oxide reduction in Pseudomonas perfectomarinus
W L Balderston,B Sherr,W J Payne +2 more
TL;DR: Acetylene did not affect the production or functioning of assimilatory nitrate or nitrite reductase in axenic cultures of Enterobacter aerogenes or Trichoderma uride and bacteria in marine sediment slurries produced measurable quantities of nitrous oxide from glucose- or acetate-dependent reduction of added nitrate.
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