Read by QxMD icon Read

Denitrifying bacteria

Takahiro Watari, Trung Cuong Mai, Daisuke Tanikawa, Yuga Hirakata, Masashi Hatamoto, Kazuaki Syutsubo, Masao Fukuda, Ngoc Bich Nguyen, Takashi Yamaguchi
Conventional aerated tank technology is widely applied for post treatment of natural rubber processing wastewater in Southeast Asia; however, a long hydraulic retention time (HRT) is required and the effluent standards are exceeded. In this study, a downflow hanging sponge (DHS) reactor was installed as post treatment of anaerobic tank effluent in a natural rubber factory in South Vietnam and the process performance was evaluated. The DHS reactor demonstrated removal efficiencies of 64.2 ± 7.5% and 55.3 ± 19...
January 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Jamal Alikhani, Ahmed Al-Omari, Haydee De Clippeleir, Sudhir Murthy, Imre Takacs, Arash Massoudieh
In this study, the endogenous respiration rate and the observed biomass yield of denitrifying methylotrophic biomass were estimated through measuring changes in denitrification rates (DNR) as a result of maintaining the biomass under methanol deprived conditions. For this purpose, activated sludge biomass from a full-scale wastewater treatment plant was kept in 10-L batch reactors for 8 days under fully aerobic and anoxic conditions at 20 °C without methanol addition. To investigate temperature effects, another biomass sample was placed under starvation conditions over a period of 10 days under aerobic conditions at 25 °C...
January 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Ning Wang, Zhi-Zhou Chang, Xi-Mei Xue, Jian-Guang Yu, Xiao-Xia Shi, Lena Q Ma, Hong-Bo Li
Biochar application to agricultural soil is an appealing approach to mitigate nitrous oxide (N2O) and methane (CH4) emissions. However, the underlying microbial mechanisms are unclear. In this study, a paddy soil slurry was incubated anaerobically for 14d with biochar amendments produced from rice straw at 300, 500, or 700°C (B300, B500, and B700) to study their influences on greenhouse gas emissions. Illumina sequencing was used to characterize shift of soil bacterial and archaeal community composition. After peaking at day 1, N2O emission then sharply decreased to low levels while CH4 started to emit at day 3 then continually increased with incubation...
January 4, 2017: Science of the Total Environment
Hongliang Dai, Xiwu Lu, Lihong Peng, Xiang Li, Zheqin Dai
An efficient one-step domestication method with mixed electron acceptors and short time post-aeration was developed for the enrichment culture of denitrifying phosphorus removal sludge. The acclimation time, performance of nitrogen and phosphorus simultaneous removal and microbial community structure were investigated to reveal the difference among the obtained phosphorus removal sludge using different acclimation ways. Results showed that the proposed method with optimal proportion of nitrite and nitrate could significantly shorten domestication time (28 d) compared with the traditional two-step method (60 d), but exerted nearly no influence on the removal efficiency of nitrogen and phosphorus...
January 2, 2017: Environmental Technology
Artur Mielcarek, Joanna Rodziewicz, Wojciech Janczukowicz, Dorota Dabrowska, Slawomir Ciesielski, Arthur Thornton, Joanna Struk-Sokołowska
The study demonstrated that citric acid, as an organic carbon source, can improve denitrification in Anaerobic Sequencing Batch Biofilm Reactor (AnSBBR). The consumption rate of the organic substrate and the denitrification rate were lower during the period of the reactor's acclimatization (cycles 1-60; 71.5 mgCOD L(-1) h(-1) and 17.81 mgN L(-1) h(-1), respectively) than under the steady state conditions (cycles 61-180; 143.8 mgCOD L(-1) h(-1) and 24.38 mgN L(-1) h(-1)). The biomass yield coefficient reached 0...
December 22, 2016: Chemosphere
Junfeng Wang, Yuhui Wang, Junhong Bai, Zhaowei Liu, Xinshan Song, Dengming Yan, Asaminew Abiyu, Zhimiao Zhao, Denghua Yan
The constructed wetland coupled with biofilm-electrode reactor (CW-BER) is a novel technology to treat wastewater with a relatively high level of total inorganic nitrogen (TIN) concentration. The main objective of this study is to investigate the effects of C/Ns, TIN concentrations, current intensities, and pH on the removal of nitrogen in CW-BER; a control system (CW) was also constructed and operated with similar influent conditions. Results indicated that the current, inorganic carbon source and hydrogen generated by the micro-electric field could significantly improve the inorganic nitrogen removal with in CW-BER, and the enhancement of average removal rate on NH3-N, NO3-N, and TIN was approximately maintained at 5-28%, 5-26%, and 3-24%, respectively...
March 2017: Bioresource Technology
Shubiao Wu, Tao Lv, Qimin Lu, Zeeshan Ajmal, Renjie Dong
The objective of this study was to assess whether the improved configuration of vertical upflow constructed wetlands (CWs) coupled with aeration in the centre part and effluent recirculation can strengthen the treatment performance of high strength anaerobic digestate supernatant. Moreover, electricity generation and bacterial community characteristics were also examined. The results indicated that intermittent aeration in vertical upflow CWs significantly enhanced organic matter (>69%, 214-401g/m(2)d) and ammonium (>92%, 62-138g/m(2)d) removal, regardless of aeration position...
December 20, 2016: Science of the Total Environment
Jing Ding, Yong-Ze Lu, Liang Fu, Zhao-Wei Ding, Yang Mu, Shuk H Cheng, Raymond J Zeng
Anaerobic oxidation of methane (AOM) contributes significantly to the global methane sink. Previously, studies of anaerobic methanotrophic (ANME) archaea have been limited as they have not been separable from their bacterial partners during the AOM process because of their dependence on the bacteria. A microbial fuel cell (MFC) is a device capable of directly transforming chemical energy to electrical energy via electrochemical reactions involving biochemical pathways. In this study, decoupling of denitrifying anaerobic methane oxidation (DAMO) archaea and DAMO bacteria was investigated in an microbial fuel cell (MFC) using methane as the fuel...
December 9, 2016: Water Research
Guo-Jun Xie, Chen Cai, Shihu Hu, Zhiguo Yuan
Partial nitritation and Anammox processes are increasingly used for nitrogen removal from anaerobic sludge digestion liquor. However, their nitrogen removal efficiency is often limited due to the production of nitrate by the Anammox reaction and the sensitivity to the nitrite to ammonium ratio. This work develops and demonstrates an innovative process that achieves complete nitrogen removal from partially nitrified anaerobic sludge digestion liquor through the use of a membrane biofilm reactor (MBfR), with methane supplied through hollow fiber membranes...
December 30, 2016: Environmental Science & Technology
Yang-Guo Zhao, Xiaoma Guo, Zonglian She, Mengchun Gao, Liang Guo
Different aeration rates and modes in an aerobic tank of an anaerobic/anoxic/aerobic (A(2)O) process were investigated to reveal their influence on nitrogen and phosphorus removal efficiency. Meanwhile, Illumina high-throughput sequencing of partial 16S rRNA gene of bacteria was conducted to monitor the abundance and composition of microbial communities. The results showed that higher aeration rate led to better nutrients' removal efficiency. The gradual-increasing aeration mode along the wastewater stream enhanced the contaminants' removal and the system achieved chemical oxygen demand, [Formula: see text]-N, total nitrogen (TN) removal rates of 72%, 96% and 51%, respectively...
December 30, 2016: Environmental Technology
Xinghui Xia, Zhimei Jia, Ting Liu, Sibo Zhang, Liwei Zhang
Suspended sediment (SPS) is ubiquitous in rivers, and SPS with different particle sizes and compositions may affect coupled nitrification-denitrification (CND) occurring on SPS significantly. However, there is no related research report. In this work, (15)N isotope tracer technique was adopted to explore the CND in systems containing SPS (8 g L(-1) and 1 g L(-1)) collected from the Yellow River with various particle sizes, including <2, 2-20, 20-50, 50-100, and 100-200 μm. The results showed that the CND occurred on SPS and the CND rate was negatively related to particle size; both nitrification and denitrification rate constants increased with decreasing SPS particle size...
January 3, 2017: Environmental Science & Technology
Junya Zhang, Yuanyue Wang, Dawei Yu, Juan Tong, Meixue Chen, Qianwen Sui, BuHe ChuLu, Yuansong Wei
Global warming effects have drawn more and more attention to studying all sources and sinks of nitrous oxide (N2O). Sludge bio-drying, as an effective sludge treatment technology, is being adopted worldwide. In this study, two aeration strategies (piles I and II) were compared to investigate the primary contributors to N2O emission during sludge bio-drying through studying the evolution of functional genes involved in nitrification (amoA, hao, and nxrA) and denitrification (narG, nirS, nirK, norB, and nosZ) by quantitative PCR (qPCR)...
December 10, 2016: Applied Microbiology and Biotechnology
Eveline M van den Berg, Marissa Boleij, J Gijs Kuenen, Robbert Kleerebezem, Mark C M van Loosdrecht
Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) compete for nitrate in natural and engineered environments. A known important factor in this microbial competition is the ratio of available electron donor and elector acceptor, here expressed as Ac/N ratio (acetate/nitrate-nitrogen). We studied the impact of the Ac/N ratio on the nitrate reduction pathways in chemostat enrichment cultures, grown on acetate mineral medium. Stepwise, conditions were changed from nitrate limitation to nitrate excess in the system by applying a variable Ac/N ratio in the feed...
2016: Frontiers in Microbiology
Hannah Gaimster, Lisa Chalklen, Mark Alston, John T Munnoch, David J Richardson, Andrew J Gates, Gary Rowley
Nitrous oxide (N2O) is a stable, ozone depleting greenhouse gas. Emissions of N2O into the atmosphere continue to rise, primarily due to the use of nitrogen-containing fertilizers by soil denitrifying microbes. It is clear more effective mitigation strategies are required to reduce emissions. One way to help develop future mitigation strategies is to address the currently poor understanding of transcriptional regulation of the enzymes used to produce and consume N2O. With this ultimate aim in mind we performed RNA-seq on a model soil denitrifier, Paracoccus denitrificans, cultured anaerobically under high N2O and low N2O emitting conditions, and aerobically under zero N2O emitting conditions to identify small RNAs (sRNAs) with potential regulatory functions transcribed under these conditions...
2016: Frontiers in Microbiology
Sophie-Marie Martirani-Von Abercron, Daniel Pacheco, Patricia Benito-Santano, Patricia Marín, Silvia Marqués
Although bacterial anaerobic degradation of mono-aromatic compounds has been characterized in depth, the degradation of polycyclic aromatic hydrocarbons (PAHs) such as naphthalene has only started to be understood in sulfate reducing bacteria, and little is known about the anaerobic degradation of PAHs in nitrate reducing bacteria. Starting from a series of environments which had suffered different degrees of hydrocarbon pollution, we used most probable number (MPN) enumeration to detect and quantify the presence of bacterial communities able to degrade several PAHs using nitrate as electron acceptor...
2016: Frontiers in Microbiology
Xinghui Xia, Ting Liu, Zhifeng Yang, Greg Michalski, Shaoda Liu, Zhimei Jia, Sibo Zhang
Present-day estimations of global nitrogen loss (N-loss) are underestimated. Commonly, N-loss from rivers is thought to be caused by denitrification only in bed-sediments. However, coupled nitrification-denitrification occurring in overlying water with suspended sediments (SPS) where oxic and anoxic/low oxygen zones may coexist is ignored for N-loss in rivers. Here the Yellow and Yangtze Rivers were taken as examples to investigate the effect of SPS, which exists in many rivers of the world, on N loss through coupled nitrification-denitrification with nitrogen stable ((15)N) isotopic tracer simulation experiments and in-situ investigation...
February 1, 2017: Science of the Total Environment
Xin Li, Yali Liu, Mingxing Chu, Aimin Liu
A novel process, inclined-plates hydrolytic tank (IHT) and membrane bioreactor (MBR), was used to treat domestic sewage continuously. In this study, the effects of carriers' addition on operational performances of IHT-MBR were studied at the hydraulic retention time of 5.4 h and the recycling rate of 200%. Experimental results indicated the removal efficiencies of chemical oxygen demand, total nitrogen and total phosphorus reached 86.8%, 82.9% and 89.6%, respectively, corresponding trans-membrane pressure decreased to 1...
November 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Mengyao Gui, Qian Chen, Tao Ma, Maosheng Zheng, Jinren Ni
Effects of heavy metals on aerobic denitrification have been poorly understood compared with their impacts on anaerobic denitrification. This paper presented effects of four heavy metals (Cd(II), Cu(II), Ni(II), and Zn(II)) on aerobic denitrification by a novel aerobic denitrifying strain Pseudomonas stutzeri PCN-1. Results indicated that aerobic denitrifying activity decreased with increasing heavy metal concentrations due to their corresponding inhibition on the denitrifying gene expression characterized by a time lapse between the expression of the nosZ gene and that of the cnorB gene by PCN-1, which led to lower nitrate removal rate (1...
November 16, 2016: Applied Microbiology and Biotechnology
Xiaomei Zhang, Xiufu Hua, Xiuping Yue
For quinoline-denitrifying degradation, very few researches focused on shortcut denitrification process and its bacterial community characteristics. In this study, complete and shortcut denitrification systems were constructed simultaneously for quinoline degradation. By calculation, specific quinoline removal rates were 0.905 and 1.123 g/(gVSS d), respectively, in the complete and shortcut systems, and the latter was 1.24 times of the former. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), high-throughput sequencing, and quantitative PCR (qPCR) techniques based on 16S rRNA were jointly applied to compare microbial community structures of two systems...
November 16, 2016: Applied Microbiology and Biotechnology
Hao Song, Jiahui Xu, Michel Lavoie, Xiaoji Fan, Guangfu Liu, Liwei Sun, Zhengwei Fu, Haifeng Qian
Physico-chemical parameters, hydrological conditions, and microbial interactions can affect the growth and persistence of cyanobacteria, but the interacting effects among these bloom-forming factors are still poorly known. This hampers our capacity to predict the occurrence of cyanobacterial bloom accurately. Here, we studied the relationship between temperature, N and P cycles, and the microbial community abundance and diversity at 0.5 m under the surface of West Lake (China) from January 21 to November 20, 2015, in order to better understand the key factors regulating temporal changes in the cyanobacterial community...
November 15, 2016: Applied Microbiology and Biotechnology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"