ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
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2018
·Vol. 25
·期 27
·27274-27282
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IF 2.8
Luo Jingyang,Zhang Qin,Wu Lijuan,Cao Jiashun,Feng Qian,Fang Fang,Chen Yinguang
1,4-Dioxane is an emerging pollutant, which widely exists in natural environments and poses potential risks to the living organisms. However, its effect on the denitrification process is still unknown. In this study, the effects of 1,4-dioxane on the denitrification process were therefore investigated by using Paracoccus denitrificans as the model denitrifier. The obtained results showed that the exposure of 1,4-dioxane exhibited remarkable lag or inhibition on the denitrification process, especially with high dose. In the control without 1,4-dioxane exposure, Paracoccus denitrificans showed high denitrification efficiency (98.5%). However, the efficiency decreased to 78.5, 63.9, and 9.3% with 0.50, 0.75, and 1.0% ( v / v ) 1,4-dioxane dose, respectively. The dose-induced inhibition of denitrification by 1,4-dioxane could be partially attributed to the negative effects on proliferation and viability of functional microorganisms by conjugating and disrupting the cell membranes. Furthermore, 1,4-dioxane caused biotoxicity to the intracellular activities of denitrifiers via disturbing carbon source utilization and interfering the key enzymes responsible for glycolysis. The decrease of microbial viability and activity inevitably resulted in the decline of key enzymes (NAR, NIR, NOR, and N 2 OR) closely related with denitrification process, which could be the direct reason for the decrease of denitrification performance.
研究领域:
环境生物学
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微生物学
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DOI
PubMed
高影响因子
CHEMOSPHERE
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2020
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IF 5.778
Jiexu Ye,Ni An,Han Chen,Zanyun Ying,Shihan Zhang,Jingkai Zhao
CO 2 is regarded as a major contributor to the global warming. CO 2 utilization is promising to reduce the CO 2 emissions. Currently, the biofixation of CO 2 using chemoautotrophs has markedly gain interest in CO 2 utilization. In this study, a newly isolated chemoautotroph, Paracoccus denitrificans PJ-1, was used for the biofixation of CO 2 under anaerobic condition . Experimental results revealed that Paracoccus denitrificans PJ-1 achieved a high carbon fixation rate (13.25 mg·L −1 ·h −1 ) which was ∼10 times faster than the previous reported chemotrophic bacteria using thiosulfate as electron donor. The best CO 2 fixation activity of Paracoccus denitrificans PJ-1 was achieved at the pH value of 9.0 and CO 2 concentration of 20 vol%. Meanwhile, a high CO 2 fixation yield of 106.03 mg·L −1 was reached. The presence of oxygen was adverse to the biofixation, indicating that strain PJ-1 was more suitable for CO 2 fixation in anaerobic environments. Carbon mass balance analysis revealed that the carbon from CO 2 was mainly fixed into the extracellular organic carbon rather than the biomass. GC-MS analysis and cbbL gene test revealed that Paracoccus denitrificans PJ-1 fixed CO 2 through the Calvin-Benson-Bassham cycle and mainly converted CO 2 to oxalic acid and succinic acid. Overall, the excellent CO 2 fixation capacity of Paracoccus denitrificans PJ-1 suggests that it had potential for CO 2 utilization.
研究领域:
环境科学
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微生物学
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生物技术
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气候变化
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DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2023
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IF 11.4
Liying Zhang,Xiaodan Ma,Qian Li,Hanlin Cui,Ke Shi,Hao Wang,Yanqing Zhang,Shuhong Gao,Zhiling Li,Ai-Jie Wang,Bin Liang
Sustainable nitrogen cycle is an essential biogeochemical process that ensures ecosystem safety and byproduct greenhouse gas nitrous oxide reduction. Antimicrobials are always co-occurring with anthropogenic reactive nitrogen sources. However, their impacts on the ecological safety of microbial nitrogen cycle remain poorly understood. Here, a denitrifying bacterial strain Paracoccus denitrificans PD1222 was exposed to a widespread broad-spectrum antimicrobial triclocarban (TCC) at environmental concentrations. The denitrification was hindered by TCC at 25 μg L–1 and was completely inhibited once the TCC concentration exceeded 50 μg L–1. Importantly, the accumulation of N2O at 25 μg L–1 of TCC was 813 times as much as the control group without TCC, which attributed to the significantly downregulated expression of nitrous oxide reductase and the genes related to electron transfer, iron, and sulfur metabolism under TCC stress. Interestingly, combining TCC-degrading denitrifying Ochrobactrum sp. TCC-2 with strain PD1222 promoted the denitrification process and mitigated N2O emission by 2 orders of magnitude. We further consolidated the importance of complementary detoxification by introducing a TCC-hydrolyzing amidase gene tccA from strain TCC-2 into strain PD1222, which successfully protected strain PD1222 against the TCC stress. This study highlights an important link between TCC detoxification and sustainable denitrification and suggests a necessity to assess the ecological risks of antimicrobials in the context of climate change and ecosystem safety.
研究领域:
环境科学
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微生物学
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气候变化
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生态系统安全
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DOI
PubMed
高影响因子
WATER RESEARCH
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2019
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IF 7.913
Meng Jiang,Xiong Zheng,Yinguang Chen
Bio-denitrification (i.e., microbial reduction of nitrate to gaseous nitrogen) is usually reported to be affected by operating and environmental parameters, such as carbon source type, pH value, and temperature. In this paper, the enhancement of denitrification performance with the elimination of nitrite accumulation and nitrous oxide emission by Shewanella oneidensis MR-1 were investigated and the mechanisms were explored. It was found that S. oneidensis MR-1 itself had marginal nitrate removal capacity, but its presence in the denitrification system of a well-studied denitrifier (Paracoccus denitrificans ) obviously enhanced nitrate removal efficiency (from 65.3% to 97.8%) and reduced nitrite accumulation (0.67 against none-detectable) and N 2 O generation (from 8.87 μm/mM-TN to none-detectable). The mechanism study showed that S. oneidensis MR-1 promoted electrons transfer activity via the formation of nanotube between cells, which resulted in the increase of denitrification enzymes activity , carbon source metabolism, ATP level and cell viability. As the generation, transfer and consumption of electrons were enhanced by S. oneidensis MR-1, the improvement of denitrification performance with reduction of nitrite accumulation and N 2 O emission was therefore achieved. Finally, the performance of denitrification enhanced by S. oneidensis MR-1 was testified by laboratory groundwater treatment experiment. This study suggested the potential role of S. oneidensis MR-1 in accelerating nitrate bio-transformation in nitrogen geochemical cycle and increasing bio-treatment of nitrate contamination with negligible harmful intermediates (nitrite and N 2 O) accumulation.
研究领域:
环境微生物学
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生物技术
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水处理
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DOI
PubMed
高影响因子
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