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Denitrifying bacteria

Ying Zhu, Xiaoyuan Zhang, Xiaogang Wu, Guanzhou Chen, Lars R Bakken, Liping Zhao, Åsa Frostegård, Xiaojun Zhang
Bacteria of Dechloromonas were recognized as potential functional important denitrifiers in a long term shell sand amended peat soil. Different microcosms in a solid matrix and slurry systems with the addition of carbon and nitrogen sources, e.g., clover leaves, glutamate, and nitrate, were established. The bacterial community structures were analyzed by pyrosequencing of the 16S rRNA gene to select the conditions for enriching bacteria of Dechloromonas. The results showed that a relatively even bacterial community in the initial soil shifted to communities dominated by a few types of nitrate reducing bacteria after the incubation, which strongly responded to the carbon substrates addition and consumption...
May 18, 2017: Letters in Applied Microbiology
Enikö Szabó, Raquel Liébana, Malte Hermansson, Oskar Modin, Frank Persson, Britt-Marie Wilén
The granular sludge process is an effective, low-footprint alternative to conventional activated sludge wastewater treatment. The architecture of the microbial granules allows the co-existence of different functional groups, e.g., nitrifying and denitrifying communities, which permits compact reactor design. However, little is known about the factors influencing community assembly in granular sludge, such as the effects of reactor operation strategies and influent wastewater composition. Here, we analyze the development of the microbiomes in parallel laboratory-scale anoxic/aerobic granular sludge reactors operated at low (0...
2017: Frontiers in Microbiology
Han Meng, Ruonan Wu, Yong-Feng Wang, Ji-Dong Gu
Denitrification plays a key role in converting reactive nitrogen species to dinitrogen gas back into the atmosphere to maintain the equilibrium of nitrogen cycling in ecosystems. In this study, functional genes of nirK and nosZ were used to detect the community structure and abundance of denitrifying microorganisms in acidic forest soils in southern China. Three sets of factors were considered for a comparison among 5 forests, including forest types (natural vs. re-vegetated), depths (surface layer vs. lower layer) and seasons (winter vs...
May 10, 2017: Journal of Environmental Management
Tamara N Nazina, Natalya M Shestakova, Ekaterina M Semenova, Alena V Korshunova, Nadezda K Kostrukova, Tatiana P Tourova, Liu Min, Qingxian Feng, Andrey B Poltaraus
The goal of this work was to study the overall genomic diversity of microorganisms of the Dagang high-temperature oilfield (PRC) and to characterize the metabolically active fraction of these populations. At this water-flooded oilfield, the microbial community of formation water from the near-bottom zone of an injection well where the most active microbial processes of oil degradation occur was investigated using molecular, cultural, radiotracer, and physicochemical techniques. The samples of microbial DNA and RNA from back-flushed water were used to obtain the clone libraries for the 16S rRNA gene and cDNA of 16S rRNA, respectively...
2017: Frontiers in Microbiology
Masashi Hatamoto, Takafumi Sato, Sho Nemoto, Takashi Yamaguchi
Anaerobic treatment of sewage has many advantages; however, the effluent contains high levels of dissolved methane. In this study, we investigated the use of a closed-type downflow hanging sponge (DHS) reactor for application of the denitrifying anaerobic methane oxidation (DAMO) reaction for nitrogen and dissolved methane removal. When using nitrate, the DAMO reaction achieved a denitrification rate of 84.4 g N m(-3) day(-1), which is close to that required for practical application of denitrification to anaerobic sewage treatment...
May 8, 2017: Applied Microbiology and Biotechnology
Signe Høgslund, Tomas Cedhagen, Samuel S Bowser, Nils Risgaard-Petersen
A substantial nitrate pool is stored within living cells in various benthic marine environments. The fate of this bioavailable nitrogen differs according to the organisms managing the intracellular nitrate (ICN). While some light has been shed on the nitrate carried by diatoms and foraminiferans, no study has so far followed the nitrate kept by gromiids. Gromiids are large protists and their ICN concentration can exceed 1000x the ambient nitrate concentration. In the present study we investigated gromiids from diverse habitats and showed that they contained nitrate at concentrations ranging from 1 to 370 mM...
2017: Frontiers in Microbiology
Yong-Jik Lee, Min-Kyu Park, Gun-Seok Park, Sang-Jae Lee, Sang Jun Lee, Bradley Seokhan Kim, Jae-Ho Shin, Dong-Woo Lee
Denitrification is a crucial process for the global nitrogen cycle through the reduction of nitrates by heterotrophic bacteria. Denitrifying microorganisms play an important role in eliminating fixed nitrogen pollutants from the ecosystem, concomitant with N2O emission. Although many microbial denitrifiers have been identified, little is known about the denitrifying ability of the genus Geobacillus. Here, we report the first complete genome sequences of Geobacillus subterraneus KCTC 3922(T), isolated from Liaohe oil field in China, and G...
April 29, 2017: Journal of Biotechnology
Yonghong Wu, Yizhou Li, Aura Ontiveros-Valencia, Luis Ordaz-Díaz, Junzhuo Liu, Chen Zhou, Bruce E Rittmann
The insufficient supply of electron donor in surface water contaminated with nitrate leads to its incomplete reduction in natural or constructed wetlands. Although the addition of organic matter (represented as chemical oxygen demand, COD) can stimulate N removal by denitrification, direct supplementation of COD creates unacceptable risks to effluent quality. An alternative for stimulating denitrification is supplying hydrogen gas (H2) as an inorganic electron donor. We evaluate an innovative means to do H2-based denitrification of surface waters in a wetland setting: the in-situ membrane biofilm reactor (isMBfR), in which H2 is delivered to a biofilm of denitrifying bacteria on demand based on the presence of nitrate...
April 25, 2017: Water Research
Xin Wen, Benzhou Gong, Jian Zhou, Qiang He, Xiaoxia Qing
Simultaneous partial nitrification, anammox and denitrification (SNAD) process was studied in a sequencing batch biofilm reactor (SBBR) fed with synthetic wastewater in a range of 2200 mgN/L ∼ 50 mgN/L. Important was an external real-time precision dissolved oxygen (DO) intelligent control system that consisted of feed forward control system and feedback control system. This DO control system permitted close control of oxygen supply according to influent concentration, effluent quality and other environmental factors in the reactor...
April 21, 2017: Water Research
Hailu Wu, Xinze Wang, Xiaojuan He, Shengbo Zhang, Rubing Liang, Jian Shen
In micro-polluted constructed wetland (CW), the low pollutant concentrations and the low COD/N ratios (chemical oxygen demand: total nitrogen in influent), make the biological treatment more difficult. It is expected that root exudates drive microbial-based transformations within plant rhizosphere. In this research, the roles of root exudates of three aquatic plants (Phragmites australis, Typha angustifolia and Cyperus alternifolius) in improving the growth of heterotrophic denitrifying bacteria were determined in a micro-polluted CW...
April 26, 2017: Science of the Total Environment
Oskar Modin
Aerobic methanotrophic bacteria use methane as their only source of energy and carbon. They release organic compounds that can serve as electron donors for co-existing denitrifiers. This interaction between methanotrophs and denitrifiers is known to contribute to nitrogen losses in natural environments and has also been exploited by researchers for denitrification of nitrate-contaminated wastewater. The purpose of this study was to develop a mathematical model describing aerobic methane oxidation coupled to denitrification in suspended-growth reactors...
May 11, 2017: Environmental Technology
Durga P Neupane, Belkis Jacquez, Anitha Sundararajan, Thiruvarangan Ramaraj, Faye D Schilkey, Erik T Yukl
Zinc homeostasis is critical for bacterial survival and is mediated largely at the transcriptional level by the regulation of zinc uptake and efflux genes. Here we use RNA-seq to assess transcriptional changes as a result of zinc limitation in the denitrifying bacterium Paracoccus denitrificans. The results identify the differential expression of 147 genes, most of which were upregulated in zinc-depleted medium. Included in this set of genes are a large number of transition metal transporters, several transcription factors, and hypothetical proteins...
2017: Frontiers in Microbiology
Bin Cui, Xiuhong Liu, Qing Yang, Jianmin Li, Xueyang Zhou, Yongzhen Peng
Partial denitrification was one of most effective ways to provide nitrite for annamox; whereas very limited research has been done to achieve nitrite accumulation in biofilm system. In this study, partial denitrification was studied in a lab-scale denitrifying biofilter (DNBF). The results showed biofilm structure variations caused the differences between nitrate specific reduction rate (NaSRR) and nitrite specific reduction rate (NiSRR), which led to nitrite accumulation in different degree at different biofilm formation phases...
April 10, 2017: Bioresource Technology
Yuli Yang, Xiaojin Li, Xiaoli Yang, Zhen He
A bioelectrochemical system (BES) containing membrane-aerated nitritation-anammox in its cathode has been developed for enhancing nitrogen removal. Long-term performance and microbial community structure were investigated. The BES using loop operation and external voltage achieved the highest total nitrogen removal efficiency of 94.8±7.7%, and COD removal of 98.2±3.3% at hydraulic retention time of 60h and the lumen pressure of 10psi. The energy consumption of the system was 0.90kWhkgN(-1) or 0.38kWhkg COD(-1)...
April 9, 2017: Bioresource Technology
Theoni Maria Massara, Simos Malamis, Albert Guisasola, Juan Antonio Baeza, Constantinos Noutsopoulos, Evina Katsou
Nitrous oxide (N2O) is an important pollutant which is emitted during the biological nutrient removal (BNR) processes of wastewater treatment. Since it has a greenhouse effect which is 265 times higher than carbon dioxide, even relatively small amounts can result in a significant carbon footprint. Biological nitrogen (N) removal conventionally occurs with nitrification/denitrification, yet also through advanced processes such as nitritation/denitritation and completely autotrophic N-removal. The microbial pathways leading to the N2O emission include hydroxylamine oxidation and nitrifier denitrification, both activated by ammonia oxidizing bacteria, and heterotrophic denitrification...
April 17, 2017: Science of the Total Environment
Zhi-Feng Zhou, Yan-Hong Yao, Ming-Xia Wang, Xiao-Hu Zuo
It has previously been confirmed that polycyclic aromatic hydrocarbons (PAHs) could be degraded by soil microbes coupling with denitrification, but the relationships among soil denitrifiers, PAHs, and nitrate under obligate anaerobic condition are still unclear. Here, co-effects of pyrene and nitrate on the activity and abundance of soil denitrifiers were investigated through a 45-day incubation experiment. Two groups of soil treatments with (N30) and without (N0) nitrate (30 mg kg(-1) dry soil) amendment were conducted, and each group contained three treatments with different pyrene concentrations (0, 30, and 60 mg kg(-1) dry soil denoted as P0, P30, and P60, respectively)...
April 18, 2017: Archives of Microbiology
Fenge Li, Mingcong Li, Wenchong Shi, Han Li, Zhongtao Sun, Zheng Gao
Denitrification was considered to be the critical process removing reactive nitrogen in estuarine ecosystem. In the present study, the abundance, diversity and community structure of nirK- and nirS-type denitrifiers were compared in sediments from the Yellow River estuary. Quantitative PCR (qPCR) showed that the abundance of the two types denitrifiers performed different distribution patterns among the samples, indicating their distinct habitat preference. Phylogenetic analysis revealed that the most sequences from cluster Ⅰ, Ⅲ, Ⅳ, Ⅴ for nirK-type denitrifiers were dominant distributed at the lower dissolved oxygen (DO) sites and sequences in other clusters were dominant at higher DO area...
April 17, 2017: Canadian Journal of Microbiology
Zhaoming Zheng, Yun Li, Jun Li, Yanzhuo Zhang, Wei Bian, Jia Wei, Baihang Zhao, Jingyue Yang
The aim of the present work was to evaluate the effects of carbon sources and chemical oxygen demand (COD)/NO2(-)-N ratios on the anammox-denitrification coupling process of the simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm. Also, the anammox activities of the SNAD biofilm were investigated under different temperature. Kaldnes rings taken from the SNAD biofilm reactor were operated in batch tests to determine the nitrogen removal rates. As a result, with the carbon source of sodium acetate, the appropriate COD/NO2(-)-N ratios for the anammox-denitrification coupling process were 1 and 2...
April 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Lihui Liu, Xiurong Xu, Yangchun Cao, Chuanjiang Cai, Hongxiao Cui, Junhu Yao
Studies proved that addition of nitrate in rumen could lead to reduction of methane emission. The mechanism of this function was involved in the competition effect of nitrate on hydrogen consumption and the inhibitory effect of generated nitrite on methanogen proliferation. The present study investigated an alternative mechanism that denitrifying anaerobic methane oxidizing (DAMO) bacteria, DAMO archaea and anammox bacteria may co-exist in rumen, therefore, more methane can be oxidized when addition of nitrate...
December 2017: AMB Express
Shuqing Li, Lina Song, Xiang Gao, Yaguo Jin, Shuwei Liu, Qirong Shen, Jianwen Zou
Manure composting is a significant source of atmospheric methane (CH4) and nitrous oxide (N2O) that are two potent greenhouse gases. The CH4 and N2O fluxes are mediated by methanogens and methanotrophs, nitrifying and denitrifying bacteria in composting manure, respectively, while these specific bacterial functional groups may interplay in CH4 and N2O emissions during manure composting. To test the hypothesis that bacterial functional gene abundances regulate greenhouse gas fluxes in windrow composting systems, CH4 and N2O fluxes were simultaneously measured using the chamber method, and molecular techniques were used to quantify the abundances of CH4-related functional genes (mcrA and pmoA genes) and N2O-related functional genes (amoA, narG, nirK, nirS, norB, and nosZ genes)...
2017: Frontiers in Microbiology
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