<i>Nitrosomonas and Nitrobacter</i>
            Interactions in Biological Nitrification

Gee, Chai Sung; Pfeffer, John T.; Suidan, Makram T.

doi:10.1061/(asce)0733-9372(1990)116:1(4)

Cited by 38 publications

(13 citation statements)

References 7 publications

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“…Previously, however, it was reported that NO 2 − -N oxidation is greatly enhanced in the presence of a robust NH 4 + -N oxidizing population while NH 4 + -N oxidation is independent of the NO 2 − -N oxidizing population (Gee et al, 1990a). Previously, however, it was reported that NO 2 − -N oxidation is greatly enhanced in the presence of a robust NH 4 + -N oxidizing population while NH 4 + -N oxidation is independent of the NO 2 − -N oxidizing population (Gee et al, 1990a).…”

Section: Interactions Between Nh 4 + -N and No 2 − -N Oxidizing Micromentioning

confidence: 98%

Single-step nitrification models erroneously describe batch ammonia oxidation profiles when nitrite oxidation becomes rate limiting

Chandran

Smets

2000

Biotechnol. Bioeng.

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Nitrification involves the sequential biological oxidation of reduced nitrogen species such as ammonium‐nitrogen (NH4+‐N) to nitrite‐nitrogen (NO2−‐N) and nitrate‐nitrogen (NO3−‐N). The adequacy of modeling NH4+‐N to NO3−‐N oxidation as one composite biochemical reaction was examined at different relative dynamics of NH4+‐N to NO2−‐N and NO2−‐N to NO3−‐N oxidation. NH4+‐N to NO2−‐N oxidation and NO2−‐N to NO3−‐N oxidation by a mixed nitrifying consortium were uncoupled using selective inhibitors allylthiourea and sodium azide. The kinetic parameters of NH4+‐N to NO2−‐N oxidation (qmax,ns and KS,ns) and NO2−‐N to NO3−‐N oxidation (qmax,nb and KS,nb) were determined by a rapid extant respirometric technique. The stoichiometric coefficients relating nitrogen removal, oxygen uptake and biomass synthesis were derived from an electron balanced equation. NH4+‐N to NO2−‐N oxidation was not affected by NO2−‐N concentrations up to 100 mg NO2−‐N L−1. NO2−‐N to NO3−‐N oxidation was noncompetitively inhibited by NH4+‐N but was not inhibited by NO3−‐N concentrations up to 250 mg NO3−‐N L−1. When NH4+‐N to NO2−‐N oxidation was the sole rate‐limiting step, complete NH4+‐N to NO3−‐N oxidation was adequately modeled as one composite process. However, when NH4+‐N to NO2−‐N oxidation and NO2−‐N to NO3−‐N oxidation were both rate limiting, the estimated lumped kinetic parameter estimates describing NH4+‐N to NO3−‐N oxidation were unrealistically high and correlated. These findings indicate that the use of single‐step models to describe batch NH4+ oxidation yields erroneous kinetic parameters when NH4+‐to‐NO2− oxidation is not the sole rate‐limiting process throughout the assay. Under such circumstances, it is necessary to quantify NH4+‐N to NO2−‐N oxidation and NO2−‐N to NO3−‐N oxidation, independently. © 2000 John Wiley & Sons, Inc. Biotechnol Bioeng 68: 396–406, 2000.

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Section: Interactions Between Nh 4 + -N and No 2 − -N Oxidizing Micromentioning

confidence: 98%

Single-step nitrification models erroneously describe batch ammonia oxidation profiles when nitrite oxidation becomes rate limiting

Chandran

Smets

2000

Biotechnol. Bioeng.

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“…We have considered a single ammonifying group because the model focuses on the mineralisation process and not on the importance of bacterial diversity in this process. We also grouped ammonium oxidisers and nitrite oxidisers into one single population that nitrify ammonium to nitrate as there is a high positive relationship between these two groups (Gee et al 1990;Grundmann and Debouzie 2000). For both populations, bacterial biomass N and C (B N and B C , mmol) is the sum of all internal bacteria compartments containing N and C (Eq.…”

Section: General Principlesmentioning

confidence: 99%

Soil microbial loop and nutrient uptake by plants: a test using a coupled C:N model of plant–microbial interactions

2006

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We have developed a spatially explicit model of plant root and soil bacteria interactions in the rhizosphere in order to formalise and study the microbial loop hypothesis that postulates that plants can stimulate the release of mineral N from the soil organic matter by providing low molecular weight C molecules to C-limited microorganisms able to liberate into the soil enzymes that degrade the organic matter. The model is based on a mechanistic description of diffusion of solutes in the soil, nutrient uptake by plants, bacterial activity and bacterial predation. Modelled soil bacterial populations grow, mediate transformations among several forms of nitrogen (mineral and organic) and compete for nitrogen with plants. Our objectives were to see if we could simulate the stimulation of turnover of the microbial loop by exudates and to study the effects of diffusion of C and N in the rhizosphere on these different processes. The model qualitatively mimics most of the characteristics of the microbial loop hypothesis. In particular, (1) plant exudates increase the growth of bacteria in the soil and (2) increase the degradation of soil organic matter and N mineralisation. (3) The increased bacterial biomass induces an increase in predator biomass and, as a result, (4) plant mineral N uptake is increased threefold compared with scenarios without exudation. However, the temporal dynamics simulated by the model are much slower than observed dynamics (the increase in uptake appears after a few months). Taking into consideration the diffusion of C and N containing molecules in soil has large effects on the spatial structure of the bacterial and predator biomass. However, the average biomass of bacteria and predators, N mineralisation and plant N uptake were not affected by these properties. The model provides a quantitative and mechanistic explanation of how plants could beneﬁt from liberating low molecular organic matter and the subsequent stimulation of the microbial loop and increases N mineralisation

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“…In fact, as the anoxic filter reaches a steady state, the distributed fractions of the two reductases will achieve constant values through the competitive uptake of nitrite and nitrate. A similar kinetic model was also used to describe the distributed biomass of Nitrosomonas and Nitrobacter in nitrification successfully (Gee et al, 1990).…”

Section: Distributed Fractions Of Nitrateand Nitrite-reductasementioning

confidence: 99%

Kinetics of denitritification and denitratification in anoxic filters

Huang

Her

Jih

1998

Biotechnol. Bioeng.

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Denitritification and denitratification in anoxic filters were performed to generate experimental data. Also, a kinetic model of denitratification that accounts for intrinsic biokinetics and hydrodynamic behavior of the biofilter is proposed. In denitritification, the simulated results are in good agreement with the experimental data; and a higher nitrite influent concentration gives a higher nitrite reduction efficiency if the denitrifying loading is kept the same. In denitratification, the intermediate nitrite tends to accumulate, and a higher denitrifying loading results in a higher nitrite effluent concentration. By inserting biological and physical parameter values into the kinetic model, the variations in distributed fractions of nitrate‐reductase (f) and nitrite‐reductase (1‐f) with different denitrifying loadings can be estimated by fitting in experimental data. The estimated f increased with an increase in denitrifying loading, implying that a higher denitrifying loading results in a higher nitrite effluent concentration. From parametric sensitivity analyses, the parameter f is more sensitive than other biological and physical parameters. Accordingly, the proposed kinetic model of denitratification can be used to predict the treatment performance of anoxic filters appropriately. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 59:52–61, 1998.

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Nitrosomonas and Nitrobacter Interactions in Biological Nitrification

Cited by 38 publications

References 7 publications

Single-step nitrification models erroneously describe batch ammonia oxidation profiles when nitrite oxidation becomes rate limiting

Single-step nitrification models erroneously describe batch ammonia oxidation profiles when nitrite oxidation becomes rate limiting

Soil microbial loop and nutrient uptake by plants: a test using a coupled C:N model of plant–microbial interactions

Kinetics of denitritification and denitratification in anoxic filters

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