Natural assemblages of marine bacteria were chosen in a batch culture experiments. The impact of varying nitrogen substrate concentrations and the substrate C：N ratios （C：Ns） on the bacterial C：N ratio （C：NB）,...Natural assemblages of marine bacteria were chosen in a batch culture experiments. The impact of varying nitrogen substrate concentrations and the substrate C：N ratios （C：Ns） on the bacterial C：N ratio （C：NB）, the bacterial growth efficiency （BGE） and ammonium regeneration was mainly examined. The C：Ns ratios varied from 5：1 （carbon limitation） to 40：1 （nitrogen limitation） with varying combinations of glucose and NO3. The C：NB ratio had positive relationship with the C：Ns ratio （r=0.93, n=8）, whose value was 3.77 when the C：Ns ratio was 5：1 but increased to 6.47 when the C：Ns ratio was 40：1. These results indicate that the C：NB ratio is a potential diagnostic tool for determining the bacterial growth in natural waters controlled by either, carbon or nitrogen. BGE decreased with the declining nitrate concentration and negatively related to C：N8 （r=-0.51, n=8）. The average value of BGE was 0.20. This value was a little lower than other reports, which could be induced by the nitrogen source used in our experiments. Finally, regeneration time of ammonium delayed with the increasing C：Ns ratio, which indicates that there were different metabolism mechanisms when bacterial growth was limited by carbon source and nitrogen source.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
[Objective]This study aimed to improve the yield of bacteriocins from lactic acid bacteria by optimizing the fermentation process for production of bacteriocins from lactic acid bacteria.[Method]By single-factor analy...[Objective]This study aimed to improve the yield of bacteriocins from lactic acid bacteria by optimizing the fermentation process for production of bacteriocins from lactic acid bacteria.[Method]By single-factor analysis,fermentation temperature,seed age,inoculation volume,fermentation duration and fermentation media p H were optimized to determine the best fermentation process.The inhibitory zone of bacteriocins from lactic acid bacteria was analyzed with oxford cup method,based on which the fermentation process was evaluated.[Result]The optimal fermentation process was optimized：fermentation temperature 37℃,seed age 14 h,inoculation volume 2%,fermentation duration 48 h,fermentation media p H 5.0.[Conclusion]Under the optimized fermentation conditions,the yield of bacteriocins from lactic acid bacteria was improved significantly.展开更多
The ammonium exceedance discharge from sewage treatment plants has a great risk to the stable operation of subsequent constructed wetlands(CWs).The effects of high ammonium shocks on submerged macrophytes and epiphyti...The ammonium exceedance discharge from sewage treatment plants has a great risk to the stable operation of subsequent constructed wetlands(CWs).The effects of high ammonium shocks on submerged macrophytes and epiphytic biofilms on the leaves of submerged macrophytes in CWs were rarely mentioned in previous studies.In this paper,the 16S rRNA sequencing method was used to investigate the variation of the microbial communities in biofilms on the leaves of Vallisneria natans plants while the growth characteristics of V.natans plants were measured at different initial ammonium concentrations.The results demonstrated that the total chlorophyll and soluble sugar synthesis of V.natans plants decreased by 51.45%and 57.16%,respectively,and malondialdehyde content increased threefold after8 days if the initial NH_(4)^(+)-N concentration was more than 5 mg/L.Algal density,bacterial quantity,dissolved oxygen,and pH increased with high ammonium shocks.The average removal efficiencies of total nitrogen and NH_(4)^(+)-N reached 73.26%and 83.94%,respectively.The heat map and relative abundance analysis represented that the relative abundances of phyla Proteobacteria,Cyanobacteria,and Bacteroidetes increased.The numbers of autotrophic nitrifiers and heterotrophic nitrification aerobic denitrification(HNAD)bacteria expanded in biofilms.In particular,HNAD bacteria of Flavobacterium,Hydrogenophaga,Acidovorax,Acinetobacter,Pseudomonas,Aeromonas,and Azospira had higher abundances than autotrophic nitrifiers because there were organic matters secreted from declining leaves of V.natans plants.The analysis of the nitrogen metabolic pathway showed aerobic denitrification was the main nitrogen removal pathway.Thus,the nitrification and denitrification bacterial communities increased in epiphytic biofilms on submerged macrophytes in constructed wetlands while submerged macrophytes declined under ammonium shock loading.展开更多
基金The Key Program of International Science and Technology Cooperation from the Ministry of Science and Technology of China under contract No.2004DFA03600the Plan of National Key Basic Research and Development Program Item of China under contract No.2001CB409703the Qingdao Natural Science Foundation of China under contract No. 04-2-JZ-88
文摘Natural assemblages of marine bacteria were chosen in a batch culture experiments. The impact of varying nitrogen substrate concentrations and the substrate C：N ratios （C：Ns） on the bacterial C：N ratio （C：NB）, the bacterial growth efficiency （BGE） and ammonium regeneration was mainly examined. The C：Ns ratios varied from 5：1 （carbon limitation） to 40：1 （nitrogen limitation） with varying combinations of glucose and NO3. The C：NB ratio had positive relationship with the C：Ns ratio （r=0.93, n=8）, whose value was 3.77 when the C：Ns ratio was 5：1 but increased to 6.47 when the C：Ns ratio was 40：1. These results indicate that the C：NB ratio is a potential diagnostic tool for determining the bacterial growth in natural waters controlled by either, carbon or nitrogen. BGE decreased with the declining nitrate concentration and negatively related to C：N8 （r=-0.51, n=8）. The average value of BGE was 0.20. This value was a little lower than other reports, which could be induced by the nitrogen source used in our experiments. Finally, regeneration time of ammonium delayed with the increasing C：Ns ratio, which indicates that there were different metabolism mechanisms when bacterial growth was limited by carbon source and nitrogen source.
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Supported by Research Project of Sichuan University of Science&Engineering(No.2011RC12,2014KY02)Scientific Research Foundation of the Education Department of Sichuan Province(No.15ZA0222)Research Project of Liquor-marking Biological Technology and Application of Key Laboratory of Sichuan Province(NJ2013-06)
文摘[Objective]This study aimed to improve the yield of bacteriocins from lactic acid bacteria by optimizing the fermentation process for production of bacteriocins from lactic acid bacteria.[Method]By single-factor analysis,fermentation temperature,seed age,inoculation volume,fermentation duration and fermentation media p H were optimized to determine the best fermentation process.The inhibitory zone of bacteriocins from lactic acid bacteria was analyzed with oxford cup method,based on which the fermentation process was evaluated.[Result]The optimal fermentation process was optimized：fermentation temperature 37℃,seed age 14 h,inoculation volume 2%,fermentation duration 48 h,fermentation media p H 5.0.[Conclusion]Under the optimized fermentation conditions,the yield of bacteriocins from lactic acid bacteria was improved significantly.
基金supported by the National Special Program of Water Environment(No.2017ZX07204002)the National Natural Science Foundation of China(No.41871082)。
文摘The ammonium exceedance discharge from sewage treatment plants has a great risk to the stable operation of subsequent constructed wetlands(CWs).The effects of high ammonium shocks on submerged macrophytes and epiphytic biofilms on the leaves of submerged macrophytes in CWs were rarely mentioned in previous studies.In this paper,the 16S rRNA sequencing method was used to investigate the variation of the microbial communities in biofilms on the leaves of Vallisneria natans plants while the growth characteristics of V.natans plants were measured at different initial ammonium concentrations.The results demonstrated that the total chlorophyll and soluble sugar synthesis of V.natans plants decreased by 51.45%and 57.16%,respectively,and malondialdehyde content increased threefold after8 days if the initial NH_(4)^(+)-N concentration was more than 5 mg/L.Algal density,bacterial quantity,dissolved oxygen,and pH increased with high ammonium shocks.The average removal efficiencies of total nitrogen and NH_(4)^(+)-N reached 73.26%and 83.94%,respectively.The heat map and relative abundance analysis represented that the relative abundances of phyla Proteobacteria,Cyanobacteria,and Bacteroidetes increased.The numbers of autotrophic nitrifiers and heterotrophic nitrification aerobic denitrification(HNAD)bacteria expanded in biofilms.In particular,HNAD bacteria of Flavobacterium,Hydrogenophaga,Acidovorax,Acinetobacter,Pseudomonas,Aeromonas,and Azospira had higher abundances than autotrophic nitrifiers because there were organic matters secreted from declining leaves of V.natans plants.The analysis of the nitrogen metabolic pathway showed aerobic denitrification was the main nitrogen removal pathway.Thus,the nitrification and denitrification bacterial communities increased in epiphytic biofilms on submerged macrophytes in constructed wetlands while submerged macrophytes declined under ammonium shock loading.
