APPLIED AND ENVIRONMENTAL MICROBIOLOGY
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2021
·Vol. 87
·期 5
·
IF 4.792
Shanshan Chen,Xianyue Jing,Yongliang Yan,Shaofu Huang,Xing Liu,Piao Chen,Shungui Zhou
Diazotrophs can produce bioavailable nitrogen from inert N2 gas by bioelectrochemical nitrogen fixation (e-BNF), which is emerging as an energy-saving and highly selective strategy for agriculture and industry. However, current e-BNF technology is impeded by requirements for NH4+ assimilation inhibitors to facilitate intracellular ammonia secretion and precious metal catalysts to generate H2 as the energy-carrying intermediate. Here, we initially demonstrate inhibitor- and catalystless extracellular NH4+ production by the diazotroph Pseudomonas stutzeri A1501 using an electrode as the sole electron donor. Multiple lines of evidence revealed that P. stutzeri produced 2.32 ± 0.25 mg/liter extracellular NH4+ at a poised potential of −0.3 V (versus standard hydrogen electrode [SHE]) without the addition of inhibitors or expensive catalysts. The electron uptake mechanism was attributed to the endogenous electron shuttle phenazine-1-carboxylic acid, which was excreted by P. stutzeri and mediated electron transfer from electrodes into cells to directly drive N2 fixation. The faradaic efficiency was 20% ± 3%, which was 2 to 4 times that of previous e-BNF attempts using the H2-mediated pathway. This study reports a diazotroph capable of producing secretable NH4+ via extracellular electron uptake, which has important implications for optimizing the performance of e-BNF systems and exploring the novel nitrogen-fixing mode of syntrophic microbial communities in the natural environment.IMPORTANCE Ammonia greatly affects global ecology, agriculture, and the food industry. Diazotrophs with an enhanced capacity of extracellular NH4+ excretion have been proven to be more beneficial to the growth of microalgae and plants, whereas most previously reported diazotrophs produce intracellular organic nitrogen in the absence of chemical suppression and genetic manipulation. Here, we demonstrate that Pseudomonas stutzeri A1501 is capable of extracellular NH4+ production without chemical suppression or genetic manipulation when the extracellular electrode is used as the sole electron donor. We also reveal the electron uptake pathway from the extracellular electron-donating partner to P. stutzeri A1501 via redox electron shuttle phenazines. Since both P. stutzeri A1501 and potential electron-donating partners (such as electroactive microbes and natural semiconductor minerals) are abundant in diverse soils and sediments, P. stutzeri A1501 has broader implications on the improvement of nitrogen fertilization in the natural environment.
研究领域:
微生物学
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环境科学
·
农业科学
✓ 已验证
DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
·
2017
·
IF 5.651
Qian Chen,Tingting Li,Mengyao Gui,Shufeng Liu,Maosheng Zheng,Jinren Ni
Anaerobic denitrification has been proved to be negatively affected by ZnO nanomaterials (NPs), but little is known about how ZnO NPs affects aerobic denitrification. In this study, inhibition of ZnO NPs to an aerobic denitrifier, Pseudomonas stutzeri PCN-1, was firstly reported. The results showed total nitrogen removal efficiency was decreased from 100% to 1.70% with the increase of ZnO NPs from 1 to 128 mg/L. The presence of ZnO NPs caused significant inhibition of gene expressions and catalytic activities of nitrate reductase and nitrite reductase, which finally led to delayed nitrate reduction and high nitrite accumulation. Further studies revealed that the deposition of nanoparticles on the bacterial surface caused by electrostatic forces and the generation of reactive oxygen species (ROS) were responsible for the cytotoxicity of ZnO NPs, where ROS played a more important role. These results were of significance to evaluating the potential ecological toxicity and risks of nanomaterials.
研究领域:
环境科学
·
微生物学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2023
·
IF 6.1
Wanqing Zhang,Haixian Liu,Yuxuan Xiao,Jie Ying,Hongwei Liu
Oxygen evolution reaction (OER) has gained increasing attention among researchers due to its significance in energy conversion. However, the sluggish kinetics of the OER present notable challenges. In this work, we present an energy-efficient, cost-effective, widely applicable, and scaled-up biological preparation method to prepare OER catalytic materials with high activity and stability based on bacteria and inexpensive Ni-Fe foam under mild conditions. Anaerobic sulfate-reducing bacterium Desulfovibrio caledoniensis and aerobic Pseudomonas stutzeri are the typical microorganisms and the OER performance of their products is not clear. Electrochemical measurements show that the catalyst prepared via D. caledoniensis exhibits a low overpotential of only 247 mV to achieve 10 mA cm −2 and a low Tafel slope of 46 mV dec -1 , while the catalyst prepared via P. stutzeri has an overpotential and Tafel slope of 259 mV and 71 mV dec -1 , respectively. Therefore, these catalysts exhibit excellent catalytic activities. Furthermore, they have a good stability of more than 40 h at 10 mA cm −2 which is far superior to that of the majority of reported NiFe-based OER catalysts. This work shows new insights into the preparation and development of high-performance OER catalysts in mild conditions.
研究领域:
能量转换
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催化
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微生物学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL TECHNOLOGY
·
2018
·
IF 1.666
Shufeng Liu,Ming Wang,Tingting Li,Qian Chen
The cytotoxicity of titanium dioxide nanoparticles (TiO2 NPs) to microorganisms has attracted great attention over the past few decades. As an important participator in the nitrogen cycle, aerobic denitrifiers have been proven to be negatively affected by TiO2 NPs, but the mechanism of this effect remains unclear. In this study, the bacteria-nanoparticle interaction was investigated by exposing an aerobic denitrifier, Pseudomonas stutzeri PCN-1 to different concentrations of TiO2 NPs at the dark condition, in order to investigate the cytotoxicity mechanism. The results illustrated that aerobic denitrification was inhibited at different TiO2 NPs concentrations from 1 to 128 mg/L, accompanied by the postponement of nitrate reduction and the accumulations of nitrite and nitrous oxide. But this inhibitory effect was mitigated with increasing TiO2 NPs concentrations. Further studies revealed that expressions of aerobic denitrification genes were also inhibited with the presence of TiO2 NPs, and the inhibition effect on napA and nirS genes was more significant than that on nosZ and cnorB, which might directly bring about the delayed nitrate reduction and hindered nitrite transfer. Moreover, the decreased toxicities at higher TiO2 NPs concentrations could be attributed to the formation of larger aggregates (>1000 nm), which greatly reduced the chance for direct interactions between NPs and bacterial membranes, as well as the interruption of denitrifying genes expressions. These findings were meaningful for the formation of deep insights into the mechanism of TiO2 NPs cytotoxicity as well as the development of strategies to control the negative effect of nanoparticles in the environment.Aerobic denitrification characteristics of strain PCN-1 under different carbon sources.
研究领域:
环境科学
·
微生物学
✓ 已验证
DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2023
·
IF 6.1
Fengjiao Hao,Shuning Chen,Huizhu Yuan,Xiaojing Yan,Daibin Yang
The plant root is a key pathway to absorb insecticides from soil and is colonized by beneficial and pathogenic microbial communities. Our study demonstrated that colonizing roots by nitrogen-fixing bacterium Pseudomonas stutzeri and pathogenic Fusarium graminearum and Pythium ultimum increased the uptake of insecticides into maize roots from soil. An alteration in the permeability of root cells contributed to this increased uptake. For the subsequent root-to-shoot translocation, the relationship between translocation and log P of the compound satisfied a Gaussian distribution. Relatively beneficial P. stutzeri can promote maize seedling growth and increase translocation, whereas Fusarium and Pythium pathogens can retard the seedling growth and reduce the translocation. Furthermore, the relationship between the concentration difference (difference of an insecticide from inoculation treatment to control) and log P also showed a Gaussian distribution. The maximum concentration difference from the Gaussian equation can be applied to assess the capacity of rhizosphere microorganisms to influence translocation.
研究领域:
植物学
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环境科学
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微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
·
2020
·
IF 4.872
Yi Qian,Yunhao Zhang,Achuo Anitta Zuh,Weichuan Qiao
Per- and polyfluoroalkyl substances (PFASs) are toxic to microorganisms , thereby affecting microbial communities in sludge and soil, but how to repair the toxicity of microorganisms remains unclear. In this study, rutin, an antioxidant, was added into a culture medium with an aerobic denitrification bacteria, Pseudomonas stutzeri , under the exposure of sodium perfluorononyloxy-benzenesulfonate (OBS) to evaluate the repair mechanisms of rutin to the toxicity of OBS to the bacteria. The results showed that rutin could repair the damage of OBS to cell structures, and reduce the death rates of the bacteria under OBS exposure. The dosage of rutin reduced the effect on the inhibition of denitrification ability of P. stutzeri under OBS exposure. Compared with the bacteria exposed to single OBS, the dosage of rutin resulted in that the death rates recovered from 96.2% to 66.4%, the growth inhibition rate decreased from 46.5% to 15.8%, the total nitrogen removal rate recovered from 66.9% to 100%, and the NO 2 − content recovered from 34.5 mg/L to 0.22 mg/L. The expressions of key denitrification genes ( napA , nirS , norB , nosZ ) were recovered after adding rutin under OBS exposure. Rutin changed the positive rate of reactive oxygen species , the relative superoxide dismutase and catalase activities in the bacteria which exposed to OBS. The mechanism by which rutin repaired the toxicity of OBS to P. stutzeri related to inhibiting the activities of antioxidant and denitrification enzymes rather than affecting the expressions of genes involved in these enzymes. This study sheds light on the repair method of micro-organics and reveals the repair mechanisms under PFASs exposure.
研究领域:
微生物学
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环境科学
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分子生物学
✓ 已验证
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Xuerui Bai,Maiqian Nie,Zhenjun Diwu,Lei Wang,Hongyun Nie,Yan Wang,Qiuyue Yin,Bo Zhang
2-Hydroxymuconic semialdehyde (2-HMS) is a useful intermediate in organic synthesis, but there are few reports for its preparation. 2-HMS accumulates in phenol-containing wastewater treated with Pseudomonas stutzeri N2. This work has studied the extraction of 2-HMS so that the phenolic wastes of high concentration may be used to produce 2-HMS. When 4.25 mmol/L phenol was degraded by Pseudomonas stutzeri N2, the accumulated 2-HMS can reach 3.79 ± 0.08 mmol/L within 30 h. A saturated solution of NaHSO 3 was added into the 2-HMS culture, and white rod-like precipitates formed gradually. Through SEM, XRD and FT-IR, the precipitates were identified as monoclinic hexagonal crystals of α-hydroxy sulfonate sodium with high purity. In the presence of NaOH, α-hydroxy sulfonate sodium could be reduced to the desired 2-HMS product. The optimized conditions were characterized to be 3 mol/L NaOH solution, 5 min and 50 °C. The conversion rate of α-hydroxy sulfonate sodium was up to 87.3 ± 0.2%, and 0.42 ± 0.02 mmol/L 2-HMS were obtained.
研究领域:
环境科学
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生物技术
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有机化学
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2021
·Vol. 11
·期 10
·1214
·
IF 4.146
Weilai Fu,Qiang Wang,Shuhui Chen,Yunshuang Wang,Yaru Wang,Peifeng Duan,Ganfeng Yi,Chao Liu,Xian Zhang,Zhiming Rao
Nitrogen pollution in water bodies is becoming increasingly serious, and how to remove nitrogen from water bodies economically and effectively has become a research hotspot. Especially in recent years, with the gradual expansion of aquaculture in China, the content of nitrite and other nitrogen-containing substances in water bodies has been increasing, which inhibits the growth of farm animals and is one of the causes of eutrophication in water bodies. In this study, a strain of bacteria was isolated from the sludge of an aquaculture fishpond and identified asPseudomonas stutzeri, which can efficiently degrade nitrite. After continuous domestication in nitrite mixed solution, the nitrite nitrogen reduction capacity ofP. stutzeriwas significantly improved. Univariate experiments aiming to optimize the degradation conditions indicate that the optimal culture conditions for strain F2 are: medium with a carbon source of sodium succinate; C/N of 18; pH of 8; culture temperature of 28 °C; and shaking speed of 210 rpm in the shaker. Under the optimal culture conditions, the NO2−-N concentration of the culture solution was 300 mg/L, and the nitrite removal rate reached 98.67%. Meanwhile, the results of the nitrogen balance test showed that the strain converted 6.1% of the initial nitrogen into cellular organic nitrogen and 62.3% into gaseous nitrogen.Keywords:nitrogen pollution;nitrite removal;domestication;Pseudomonas stutzeri
研究领域:
环境科学
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微生物学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Bingmei Su,Wen Yang,Yi Zhou,Juan Lin
Ectoine, so-called tetrahydropyrimidine, is an important osmotic adjustment solute and widely applied in cosmetics and protein protectant. Some attempts have been made to improve the ectoine productivity. However, the strains with both high ectoine production capacity and high glucose conversion were still absent so far. Aim to construct a strain for efficiently producing ectoine, ectoine synthetic gene cluster ectABC from Pseudomonas stutzeri was overexpressed in E. coli BL21 (DE3). The ection production was improved by 382 % (ectoine titer increased from 1.73 g/L to 8.33 g/L) after the rational design of rate-limiting enzyme L-2,4-diaminobutyrate transaminase EctB ps (protein engineering) combined with the metabolic engineering that focused on the enrichment and conversion of precursors. The final strain YW20 was applied to overproduce ectoine in fed-batch fermentation and yield 68.9 g/L of ectoine with 0.88 g/L/h of space-time yield and the highest glucose conversion reported [34 % (g/g)]. From the fermentation broth, ectoine was purified with 99.7 % purity and 79.8 % yield. This study successfully provided an engineered strain as well as an efficient method for the industrial bio-synthesis and preparation of ectoine.
研究领域:
生物技术
·
微生物学
·
生物化工
✓ 已验证
产品关联
DOI
PubMed
高影响因子
iScience
·
2022
·
IF 6.107
Fanyang Lv,Yuhua Zhan,Wei Lu,Xiubin Ke,Yahui Shao,Yiyuan Ma,Juan Zheng,Zhimin Yang,Shanshan Jiang,Liguo Shang,Yao Ma,Lei Cheng,Claudine Elmerich,Yongliang Yan,Min Lin
Summary Bacteria of the genus Pseudomonas consume preferred carbon substrates in nearly reverse order to that of enterobacteria, and this process is controlled by RNA-binding translational repressors and regulatory ncRNA antagonists. However, their roles in microbe-plant interactions and the underlying mechanisms remain uncertain. Here we show that root-associated diazotrophic Pseudomonas stutzeri A1501 preferentially catabolizes succinate, followed by the less favorable substrate citrate, and ultimately glucose. Furthermore, the Hfq/Crc/CrcZY regulatory system orchestrates this preference and contributes to optimal nitrogenase activity and efficient root colonization. Hfq has a central role in this regulatory network through different mechanisms of action, including repressing the translation of substrate-specific catabolic genes, activating the nitrogenase gene nifH posttranscriptionally, and exerting a positive effect on the transcription of an exopolysaccharide gene cluster. Our results illustrate an Hfq-mediated mechanism linking carbon metabolism to nitrogen fixation and root colonization, which may confer rhizobacteria competitive advantages in rhizosphere environments.
研究领域:
微生物学
·
植物科学
·
分子生物学
✓ 已验证
DOI
PubMed
高影响因子
BMC MICROBIOLOGY
·
2016
·Vol. 16
·期 1
·1-11
·
IF 2.581
Wang Dan,Zhu Fengqiu,Wang Qian,Rensing Christopher,Yu Peng,Gong Jing,Wang Gejiao
Background Microbial antimonite [Sb(III)] oxidation converts toxic Sb(III) into less toxic antimonate [Sb(V)] and plays an important role in the biogeochemical Sb cycle. Currently, little is known about the mechanisms underlying bacterial Sb(III) resistance and oxidation. Results In this study, Tn5 transposon mutagenesis was conducted in the Sb(III)-oxidizing strain Pseudomonas stutzeri TS44 to isolate the genes responsible for Sb(III) resistance and oxidation. An insertion mutation into gshA, encoding a glutamate cysteine ligase involved in glutathione biosynthesis, generated a strain called P. stutzeri TS44-gshA 540 . This mutant strain was complemented with a plasmid carrying gshA to generate strain P. stutzeri TS44-gshA-C. The transcription of gshA , the two superoxide dismutase (SOD)-encoding genes sodB and sodC as well as the catalase-encoding gene katE was monitored because gshA -encoded glutamate cysteine ligase is responsible for the biosynthesis of glutathione (GSH) and involved in the cellular stress defense system as are superoxide dismutase and catalase responsible for the conversion of ROS. In addition, the cellular content of total ROS and in particular H 2 O 2 was analyzed. Compared to the wild type P. stutzeri TS44 and TS44-gshA-C, the mutant P. stutzeri TS44-gshA 540 had a lower GSH content and exhibited an increased content of total ROS and H 2 O 2 and increased the Sb(III) oxidation rate. Furthermore, the transcription of sodB , sodC and katE was induced by Sb(III). A positive linear correlation was found between the Sb(III) oxidation rate and the H 2 O 2 content ( R
2 = 0.97), indicating that the accumulated H 2 O 2 is correlated to the increased Sb(III) oxidation rate. Conclusions Based on the results, we propose that a disruption of the pathway involved in ROS-protection allowed H 2 O 2 to accumulate. In addition to the previously reported enzyme mediated Sb(III) oxidation, the mechanism of bacterial oxidation of Sb(III) to Sb(V) includes a non-enzymatic mediated step using H 2 O 2 as the oxidant.
研究领域:
微生物学
·
环境科学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Mengyao Gui,Hongwei Yang,Erming Ouyang
Polystyrene nanoplastics (NPs), ubiquitous contaminants in aquatic ecosystems, are known to impede conventional anoxic denitrification processes. However, their effects on aerobic denitrification systems remained poorly understood. This study systematically elucidates the mechanistic interactions between polystyrene NPs and aerobic denitrification performance. Results revealed polystyrene NPs caused concentration-dependent suppression of denitrification efficiency in the aerobic denitrifier Pseudomonas stutzeri PCN-1 under controlled laboratory conditions (aerobic, 30 ℃). At NPs concentrations escalating from 100 to 1000 μg L⁻¹ , nitrate removal rates decreased markedly (0.4–3.3 mg L⁻¹ h⁻¹), paralleled by progressive accumulation of nitrite (8.8–87.2 mg L⁻¹) and N₂O (31.2–58.3 mg L⁻¹). Mechanistic analyses revealed that polystyrene NPs induced biotoxic effects through two primary pathways: (1) disruption of cellular membrane integrity and (2) excessive generation of reactive oxygen species (ROS), collectively impairing bacterial viability and metabolic activity. Furthermore, critical denitrification processes were compromised, including diminished electron transport system activity, reduced catalytic activities of key denitrification enzymes, and downregulation in transcriptional expression of functional genes (e.g. napA , nirS , cnorB , and nosZ ). These multilevel inhibitions collectively contributed to the observed deterioration in nitrogen removal capacity. This investigation provides novel insights into the ecotoxicological risks posed by NPs to microbial nitrogen cycling in aquatic environments.
研究领域:
环境微生物学
·
生态毒理学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）