Acetochlor is an increasingly used herbicide on corn in North China. Currently, the effect of acetochlor on soil ammonia-oxidizing bacteria (AOB) communities is not well documented. Here, we studied the diversity and ...Acetochlor is an increasingly used herbicide on corn in North China. Currently, the effect of acetochlor on soil ammonia-oxidizing bacteria (AOB) communities is not well documented. Here, we studied the diversity and community composition of AOB in soil amended with three concentrations of acetochlor (50, 150, 250 mg/kg) and the control (0 mg acetochlor/kg soil) in a microcosm experiment by PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) and the phylogenetic analysis of excised ...展开更多
A molecular biology method, fluorescent in situ hybridization（FISH）, in which the pre-treatment was improved in allusion to the media of the constructed wetlands（CW）, e.g. the soil and the grit, was used to invest...A molecular biology method, fluorescent in situ hybridization（FISH）, in which the pre-treatment was improved in allusion to the media of the constructed wetlands（CW）, e.g. the soil and the grit, was used to investigate the vertical distribution characteristics of ammonia-oxidizing bacteria（AOB） quantity and the relation with oxidation-reduction potential（ORP） in the Typha latifolia constructed wetlands under three different Ioadings in summer from May to September. Results showed that the quantity of the AOB decreased in the Typha latifolia CW with the increase of vertical depth. However, the AOB quantity was 2-4 times the quantity of the control in the root area. Additionally, ORP in the rhizosphere was found to be higher than other areas, which showed that Typha latifolia CW was in an aerobic state in summer when using simulated non-point sewage at the rural area of Taihu Lake in China and small town combined sewage.展开更多
The present study investigates the enrichment of anaerobic ammonium oxidation(anammox)bacteria in the marine environment using sediment samples obtained from the East China Sea and discusses the nitrogen removal effic...The present study investigates the enrichment of anaerobic ammonium oxidation(anammox)bacteria in the marine environment using sediment samples obtained from the East China Sea and discusses the nitrogen removal efficiency of marine anammox bioreactor.Enrichment of anammox bacteria with simultaneous removal of nitrite and ammonium ions was observed in the Anaerobic Sequencing Batch Reactor under a total nitrogen loading rate of 0.37kg-N m-3day-1.In this study,The nitrogen removal efficiency was up to 80%and the molar-reaction ratio of ammonium,nitrite and nitrate was 1.0:1.22:0.22 which was a little different from a previously reported ratio of 1.0:1.32:0.26 in a freshwater system.展开更多
The concept of anaerobic ammonium oxidation(ANAMMOX) is presently of great interest. The functional bacteria belonging to the Planctomycete phylum and their metabolism are investigated by microbiologists. Meanwhile,th...The concept of anaerobic ammonium oxidation(ANAMMOX) is presently of great interest. The functional bacteria belonging to the Planctomycete phylum and their metabolism are investigated by microbiologists. Meanwhile,the ANAMMOX is equally valuable in treatment of ammonium-rich wastewaters. Related processes including partial nitritation-ANAMMOX and completely autotrophic nitrogen removal over nitrite(CANON) have been developed,and lab-scale experiments proved that both processes were quite feasible in engineering with appropriate control. Successful full-scale practice in the Netherlands will ac-celerate application of the process in future. This review introduces the microbiology and more focuses on application of the ANAMMOX process.展开更多
Ammonia-oxidizing archaea(AOA),ammonia-oxidizing bacteria(AOB),and anaerobic ammonia-oxidation(anammox)bacteria are very important contributors to nitrogen cycling in natural environments.Functional gene abundances of...Ammonia-oxidizing archaea(AOA),ammonia-oxidizing bacteria(AOB),and anaerobic ammonia-oxidation(anammox)bacteria are very important contributors to nitrogen cycling in natural environments.Functional gene abundances of these microbes were believed to be well relevant to N-cycling in groundwater systems,especially in the Pearl River Delta(PRD)groundwater with unique high intrinsic ammonia concentrations.In this research,20 sediment samples from two in the PRD were collected for porewater chemistry analysis and quantification of N-cycling related genes,including archaeal and bacterial amoA gene and anammox 16S ribosomal Ribonucleic Acid(rRNA)gene.Quantitative Polymerase Chain Reaction(qPCR)results showed that gene abundances of AOA,AOB,and anammox bacteria ranged from 3.13×10^(5)to 3.21×10^(7),1.83×10^(4)to 2.74×10^(6),and 9.27×10^(4)to 8.96×10^(6)copies/g in the sediment of the groundwater system,respectively.Anammox bacteria and AOA dominated in aquitards and aquifers,respectively,meanwhile,the aquitard-aquifer interfaces were demonstrated as ammonium-oxidizing hotspots in the aspect of gene numbers.Gene abundances of nitrifiers were analyzed with geochemistry profiles.Correlations between gene numbers and environmental variables indicated that the gene abundances were impacted by hydrogeological conditions,and microbial-derived ammonium loss was dominated by AOA in the northwest PRD and by anammox bacteria in the southeast PRD.展开更多
The aim of this work is to identify the range of applicability of Arrhenius type temperature dependence for Ammonia Oxidizing Bacteria （AOB） subjected to tem- perature time gradients through continuous titrimetric t...The aim of this work is to identify the range of applicability of Arrhenius type temperature dependence for Ammonia Oxidizing Bacteria （AOB） subjected to tem- perature time gradients through continuous titrimetric tests. An innovative online differential titrimetric technique was used to continuously monitor the maximum biologic ammonia oxidation rate of the biomass selected in a pilot scale membrane bioreactor, as a function of temperature time gradients. The monitoring technique is based on the measurement of alkalinity and hydrogen peroxide con- sumption rates in two parallel reactors operated in non- limiting substrate conditions for AOB; both reactors were continuously fed with mixed liquor and in one of them AOB were inhibited with allylthiourea. The effects of temperature decrease rates in the range 1 to 4℃h^-1 were evaluated by controlling the titrimetric reactor in the temperature range 10℃-20℃. The dependence of growth kinetics on temperature time gradients and the range of applicability of Arrhenius model for temperature depen- dency of AOB growth kinetics were assessed. The Arrhenius model was found to be accurate only with temperature gradients lower than 2℃·h^-1. The estimated Arrhenius coefficients （θ） were shown to increase from 1.07 to 1.6 when the temperature decrease rate reached 4℃.h^-1.展开更多
基金the Natural Science Foun-dation for Young Scientists of China (No. 40701088)
文摘Acetochlor is an increasingly used herbicide on corn in North China. Currently, the effect of acetochlor on soil ammonia-oxidizing bacteria (AOB) communities is not well documented. Here, we studied the diversity and community composition of AOB in soil amended with three concentrations of acetochlor (50, 150, 250 mg/kg) and the control (0 mg acetochlor/kg soil) in a microcosm experiment by PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) and the phylogenetic analysis of excised ...
文摘A molecular biology method, fluorescent in situ hybridization（FISH）, in which the pre-treatment was improved in allusion to the media of the constructed wetlands（CW）, e.g. the soil and the grit, was used to investigate the vertical distribution characteristics of ammonia-oxidizing bacteria（AOB） quantity and the relation with oxidation-reduction potential（ORP） in the Typha latifolia constructed wetlands under three different Ioadings in summer from May to September. Results showed that the quantity of the AOB decreased in the Typha latifolia CW with the increase of vertical depth. However, the AOB quantity was 2-4 times the quantity of the control in the root area. Additionally, ORP in the rhizosphere was found to be higher than other areas, which showed that Typha latifolia CW was in an aerobic state in summer when using simulated non-point sewage at the rural area of Taihu Lake in China and small town combined sewage.
文摘The present study investigates the enrichment of anaerobic ammonium oxidation(anammox)bacteria in the marine environment using sediment samples obtained from the East China Sea and discusses the nitrogen removal efficiency of marine anammox bioreactor.Enrichment of anammox bacteria with simultaneous removal of nitrite and ammonium ions was observed in the Anaerobic Sequencing Batch Reactor under a total nitrogen loading rate of 0.37kg-N m-3day-1.In this study,The nitrogen removal efficiency was up to 80%and the molar-reaction ratio of ammonium,nitrite and nitrate was 1.0:1.22:0.22 which was a little different from a previously reported ratio of 1.0:1.32:0.26 in a freshwater system.
基金Project supported by the National Hi-Tech Research and Develop-ment Program (863) of China (No. 2006AA06Z332)the Scienceand Technology Foundation for Key Project of Zhejiang Province (No2003C13005), China
文摘The concept of anaerobic ammonium oxidation(ANAMMOX) is presently of great interest. The functional bacteria belonging to the Planctomycete phylum and their metabolism are investigated by microbiologists. Meanwhile,the ANAMMOX is equally valuable in treatment of ammonium-rich wastewaters. Related processes including partial nitritation-ANAMMOX and completely autotrophic nitrogen removal over nitrite(CANON) have been developed,and lab-scale experiments proved that both processes were quite feasible in engineering with appropriate control. Successful full-scale practice in the Netherlands will ac-celerate application of the process in future. This review introduces the microbiology and more focuses on application of the ANAMMOX process.
基金This study was financially supported by the General Research Fund of the Research Grants Council,the Hong Kong Special Administrative Region,China(HKU 702612P and HKU 703010P).
文摘Ammonia-oxidizing archaea(AOA),ammonia-oxidizing bacteria(AOB),and anaerobic ammonia-oxidation(anammox)bacteria are very important contributors to nitrogen cycling in natural environments.Functional gene abundances of these microbes were believed to be well relevant to N-cycling in groundwater systems,especially in the Pearl River Delta(PRD)groundwater with unique high intrinsic ammonia concentrations.In this research,20 sediment samples from two in the PRD were collected for porewater chemistry analysis and quantification of N-cycling related genes,including archaeal and bacterial amoA gene and anammox 16S ribosomal Ribonucleic Acid(rRNA)gene.Quantitative Polymerase Chain Reaction(qPCR)results showed that gene abundances of AOA,AOB,and anammox bacteria ranged from 3.13×10^(5)to 3.21×10^(7),1.83×10^(4)to 2.74×10^(6),and 9.27×10^(4)to 8.96×10^(6)copies/g in the sediment of the groundwater system,respectively.Anammox bacteria and AOA dominated in aquitards and aquifers,respectively,meanwhile,the aquitard-aquifer interfaces were demonstrated as ammonium-oxidizing hotspots in the aspect of gene numbers.Gene abundances of nitrifiers were analyzed with geochemistry profiles.Correlations between gene numbers and environmental variables indicated that the gene abundances were impacted by hydrogeological conditions,and microbial-derived ammonium loss was dominated by AOA in the northwest PRD and by anammox bacteria in the southeast PRD.
文摘The aim of this work is to identify the range of applicability of Arrhenius type temperature dependence for Ammonia Oxidizing Bacteria （AOB） subjected to tem- perature time gradients through continuous titrimetric tests. An innovative online differential titrimetric technique was used to continuously monitor the maximum biologic ammonia oxidation rate of the biomass selected in a pilot scale membrane bioreactor, as a function of temperature time gradients. The monitoring technique is based on the measurement of alkalinity and hydrogen peroxide con- sumption rates in two parallel reactors operated in non- limiting substrate conditions for AOB; both reactors were continuously fed with mixed liquor and in one of them AOB were inhibited with allylthiourea. The effects of temperature decrease rates in the range 1 to 4℃h^-1 were evaluated by controlling the titrimetric reactor in the temperature range 10℃-20℃. The dependence of growth kinetics on temperature time gradients and the range of applicability of Arrhenius model for temperature depen- dency of AOB growth kinetics were assessed. The Arrhenius model was found to be accurate only with temperature gradients lower than 2℃·h^-1. The estimated Arrhenius coefficients （θ） were shown to increase from 1.07 to 1.6 when the temperature decrease rate reached 4℃.h^-1.
