Evaluation of nitrate removal by continuous culturing of an aerobic denitrifying bacterium, Paracoccus pantotrophus

2006 ◽  
Vol 54 (8) ◽  
pp. 219-228 ◽  
Author(s):  
K. Hasegawa-Kurisu ◽  
Y. Otani ◽  
K. Hanaki
Keyword(s):  
Bacterial Community ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Removal Rate ◽  
Nitrate Removal ◽  
Community Analysis ◽  
Carbon Limitation ◽  
High Concentration ◽  
Gradient Gel Electrophoresis ◽  
Pure Cultures ◽  
Paracoccus Pantotrophus

Nitrate removal under aerobic conditions was investigated using pure cultures of Paracoccus pantotrophus, which is a well-known aerobic-denitrifying (AD) bacterium. When a high concentration of cultures with a high carbon/nitrogen (C/N) ratio was preserved at the beginning of batch experiments, subsequently added nitrate was completely removed. When continuous culturing was perpetuated, a high nitrate removal rate (66.5%) was observed on day 4 post-culture, although gradual decreases in AD ability with time were observed. The attenuation in AD ability was probably caused by carbon limitation, because when carbon concentration of inflow water was doubled, nitrate removal efficiency improved from 18.1% to 59.6%. Bacterial community analysis using the polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) method showed that P. pantotrophus disappeared in the suspended medium on day 8 post-culture, whereas other bacterial communities dominated by Acidovorax sp. appeared. Interestingly, this replaced bacterial community also showed AD ability. As P. pantotrophus was detected as attached colonies around the membrane and bottom of the reactor, this bacterium can therefore be introduced in a fixed form for treatment of wastewater containing nitrate with a high C/N ratio.

Microbial community analysis in the autotrophic denitrification process using spent sulfidic caustic by denaturing gradient gel electrophoresis of PCR-amplified genes

2011 ◽  
Vol 63 (3) ◽  
pp. 475-483 ◽  
Author(s):  
J. -H. Lee ◽  
S. -M. Lee ◽  
G. -C. Choi ◽  
H. -S. Park ◽  
D. -H. Kang ◽  
...  
Keyword(s):  
Microbial Community ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Carbon Sources ◽  
Community Analysis ◽  
Microbial Community Analysis ◽  
Autotrophic Denitrification ◽  
High Concentration ◽  
Spent Sulfidic Caustic ◽  
Gradient Gel Electrophoresis ◽  
Sulfidic Caustic

Spent sulfidic caustic (SSC) produced from petrochemical plants contains a high concentration of hydrogen sulfide and alkalinity, and some almost non-biodegradable organic compounds such as benzene, toluene, ethylbenzene and xylenes (BTEX). SSC is mainly incinerated with auxiliary fuel, leading to secondary pollution problems. The reuse of this waste is becoming increasingly important from economic and environmental viewpoints. To denitrify wastewater with low COD/N ratio, additional carbon sources are required. Thus, autotrophic denitrification has attracted increasing attention. In this study, SSC was injected as an electron donor for sulfur-based autotrophic denitrification in the modified Ludzack-Ettinger (MLE) process. The efficiencies of nitrification, COD, and total nitrogen (TN) removal were evaluated with varying SSC dosage. Adequate SSC injection exhibited stable autotrophic denitrification. No BTEX were detected in the monitored BTEX concentrations of the effluent. To analyse the microbial community of the MLE process, PCR-DGGE based on 16 S rDNA with EUB primers, TD primers and nirK gene with nirK primers was performed in order to elucidate the application of the MLE process to SSC.

Microbial Community Analysis of Underground Drinking Water Using Denaturing Gradient Gel Electrophoresis and Flow Cytometry Technologies

2014 ◽  
Vol 700 ◽  
pp. 519-524 ◽  
Author(s):  
Jie Liu ◽  
Yan Li Ding ◽  
Mark Bartlam ◽  
Ying Ying Wang
Keyword(s):  
Drinking Water ◽  
Microbial Community ◽  
Rural Areas ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Poyang Lake ◽  
Removal Rate ◽  
Underground Water ◽  
Water Sources ◽  
Gradient Gel Electrophoresis ◽  
Bacteria And Fungi

Underground water is directly used as drinking water in most rural areas of developing countries due to limitations in infrastructure. As an important indicator of drinking water quality, however, microbial quality has been largely ignored for a long time. Microbial quality poses a great threat to the safety of underground drinking water, especially in rural areas. The current study compared microbial abundance and community structure of three different water sources, i.e. underground water, Poyang Lake and Hai River, combined with flow cytometry (FCM) and denaturing gradient gel electrophoresis (DGGE). FCM results showed that the bacterial concentration of underground water is the lowest (1.037×106cell/ml) of the three water sources, but still approximates that of the Poyang Lake. The removal rate of bacteria after filtration through a 0.45μm-pore-size filter is 98.16% in underground water. The removal rate for Poyang Lake and Hai River is much lower (i.e. 66.57% and 74.17% respectively). DGGE profiles demonstrated that the microbial community structure in underground water shares higher similarity to Poyang Lake (51.0% and 53.1% similarity for bacteria and fungi respectively) than Hai River. The microbial diversity index (i.e. Shannon-Weaver index) for bacteria and fungi are 2.906 and 2.847 respectively in underground water, which is lower than in Poyang Lake. The evenness (i.e. Simpson index) of groundwater was lowest among the three water sources tested. The results suggested that groundwater has a complex microbial community and hence it is critical to apply necessary hygienic barriers to remove microbes for the safety of underground drinking water.

scholarly journals Effects of Dietary Fat Source and Subtherapeutic Levels of Antibiotic on the Bacterial Community in the Ileum of Broiler Chickens at Various Ages

2002 ◽  
Vol 68 (12) ◽  
pp. 5918-5924 ◽  
Author(s):  
Ane Knarreborg ◽  
Mary Alice Simon ◽  
Ricarda M. Engberg ◽  
Bent Borg Jensen ◽  
Gerald W. Tannock
Keyword(s):  
Bacterial Community ◽  
Dietary Fat ◽  
Broiler Chickens ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Dietary Supplementation ◽  
Toxin Gene ◽  
Bacterial Enumeration ◽  
Gradient Gel Electrophoresis ◽  
Different Strains ◽  
Dietary Treatments

ABSTRACT The effect of dietary fat source (soy oil or a mixture of lard and tallow) and dietary supplementation with antibiotics (a combination of avilamycin at 10 mg kg of feed−1 and salinomycin at 40 mg kg of feed−1) on the bacterial community in the ileum of broiler chickens at different ages (7, 14, 21, and 35 days) was studied using PCR with denaturing gradient gel electrophoresis (DGGE) analysis and bacteriological culture. The bacterial origin of fragments in DGGE profiles was identified by sequencing. Bacterial enumeration results, together with PCR-DGGE profiles, showed that the composition of the microflora was age dependent and influenced by dietary fat source and antibiotic supplementation. An increased incidence of streptococci, enterobacteria, and Clostridium perfringens with age of the chickens was demonstrated. Lactobacilli and C. perfringens were the bacterial groups most strongly affected by the dietary treatments. Moreover, different strains (clonal variants of the alpha-toxin gene) of C. perfringens type A were detected in response to age, dietary fat source, and dietary supplementation with antibiotics.

scholarly journals Simultaneous Cellulose Degradation and Electricity Production by Enterobacter cloacae in a Microbial Fuel Cell

2009 ◽  
Vol 75 (11) ◽  
pp. 3673-3678 ◽  
Author(s):  
Farzaneh Rezaei ◽  
Defeng Xing ◽  
Rachel Wagner ◽  
John M. Regan ◽  
Tom L. Richard ◽  
...  
Keyword(s):  
16S Rrna ◽  
Microbial Fuel Cells ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Cellulose Degradation ◽  
Enterobacter Cloacae ◽  
Community Analysis ◽  
Electricity Production ◽  
Rrna Gene ◽  
16S Rrna Sequence ◽  
Gradient Gel Electrophoresis

ABSTRACT Electricity can be directly generated by bacteria in microbial fuel cells (MFCs) from many different biodegradable substrates. When cellulose is used as the substrate, electricity generation requires a microbial community with both cellulolytic and exoelectrogenic activities. Cellulose degradation with electricity production by a pure culture has not been previously demonstrated without addition of an exogenous mediator. Using a specially designed U-tube MFC, we enriched a consortium of exoelectrogenic bacteria capable of using cellulose as the sole electron donor. After 19 dilution-to-extinction serial transfers of the consortium, 16S rRNA gene-based community analysis using denaturing gradient gel electrophoresis and band sequencing revealed that the dominant bacterium was Enterobacter cloacae. An isolate designated E. cloacae FR from the enrichment was found to be 100% identical to E. cloacae ATCC 13047T based on a partial 16S rRNA sequence. In polarization tests using the U-tube MFC and cellulose as a substrate, strain FR produced 4.9 ± 0.01 mW/m2, compared to 5.4 ± 0.3 mW/m2 for strain ATCC 13047T. These results demonstrate for the first time that it is possible to generate electricity from cellulose using a single bacterial strain without exogenous mediators.

Bacterial diversity in antibiotic wastewater treatment

2013 ◽  
Vol 68 (12) ◽  
pp. 2676-2682 ◽  
Author(s):  
J. Han ◽  
L. Y. Wang ◽  
B. Y. Cai
Keyword(s):  
Wastewater Treatment ◽  
Bacterial Diversity ◽  
Industrial Wastewater ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Diversity Index ◽  
Batch Reactor ◽  
Community Analysis ◽  
Bacterial Strains ◽  
Wiener Diversity Index ◽  
Gradient Gel Electrophoresis

The bacterial diversity of an antibiotic industrial wastewater treatment system was analyzed to provide the information required for further optimization of this process and for identification of bacterial strains that perform improved degradation of antibiotic industrial wastewater. The total bacterial DNA of samples collected at three stages (aeration, precipitation, and idle) during the sequencing batch reactor (SBR) process were analyzed by polymerase chain reaction–denaturing gradient gel electrophoresis (PCR-DGGE) of the 16 s rDNA V3 regions. Community analysis was conducted in terms of the richness value (S), the dominance degree and the Shannon–Wiener diversity index (H). Rich bacterial diversity was apparent in the aeration stage of the SBR process, and the number of bands in the aeration stage was more abundant than that in the precipitation and idle stages. The DGGE analysis showed 15 bands, six of which were uncultured bacteria, and included one anaerobic and five aerobic bacteria. The microbial community in the aeration stage was the most complex of the whole SBR process, while the dominant bacteria differed in each reaction stage. These results demonstrate the cyclical dynamic changes in the bacterial population during the SBR process for the treatment of antibiotic industrial wastewater.

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