Frontiers in Microbiology
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2016
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IF 4.165
Han Rui,Li Fangbai,Liu Tongxu,Li Xiaomin,Wu Yundang,Wang Ying,Chen Dandan
It is widely recognized that the outer membrane c-type cytochromes (OM c-Cyts) of metal-reducing bacteria play a key role in microbial metal reduction processes. However, the in situ redox status of OM c-Cyts during microbial metal reduction processes remain poorly understood. In this study, diffuse-transmission UV/Vis spectroscopy is used to investigate the in situ spectral reaction of Cr(VI) reduction by c-Cyts in intact Shewanella oneidensis MR-1 cells under different incubation conditions. The reduced c-Cyts decreased transiently at the beginning and then recovered gradually over time. The Cr(VI) reduction rates decreased with increasing initial Cr(VI) concentrations, and Cr(III) was identified as a reduced product. The presence of Cr(III) substantially inhibited Cr(VI) reduction and the recovery of reduced c-Cyts, indicating that Cr(III) might inhibit cell growth. Cr(VI) reduction rates increased with increasing cell density. The highest Cr(VI) reduction rate and fastest recovery of c-Cyts were obtained at pH 7.0 and 30∘C, with sodium lactate serving as an electron donor. The presence of O2 strongly inhibited Cr(VI) reduction, suggesting that O2 might compete with Cr(VI) as an electron acceptor in cells. This study provides a case of directly examining in vivo reaction properties of an outer-membrane enzyme during microbial metal reduction processes under non-invasive physiological conditions.
研究领域:
微生物学
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环境科学
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生物化学
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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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PubMed
高影响因子
Nature Communications
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2020
·Vol. 11
·期 1
·1-11
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IF 12.121
Yang Chenhui,Aslan Hüsnü,Zhang Peng,Zhu Shoujun,Xiao Yong,Chen Lixiang,Khan Nasar,Boesen Thomas,Wang Yuanlin,Liu Yang,Wang Lei,Sun Ye,Feng Yujie,Besenbacher Flemming,Zhao Feng,Yu Miao
Bioelectricity generation, by Shewanella oneidensis ( S. oneidensis ) MR-1, has become particularly alluring, thanks to its extraordinary prospects for energy production, pollution treatment, and biosynthesis. Attempts to improve its technological output by modification of S. oneidensis MR-1 remains complicated, expensive and inefficient. Herein, we report on the augmentation of S. oneidensis MR-1 with carbon dots (CDs). The CDs-fed cells show accelerated extracellular electron transfer and metabolic rate, with increased intracellular charge, higher adenosine triphosphate level, quicker substrate consumption and more abundant extracellular secretion. Meanwhile, the CDs promote cellular adhesion, electronegativity, and biofilm formation. In bioelectrical systems the CDs-fed cells increase the maximum current value, 7.34 fold, and power output, 6.46 fold. The enhancement efficacy is found to be strongly dependent on the surface charge of the CDs. This work demonstrates a simple, cost-effective and efficient route to improve bioelectricity generation of S. oneidensis MR-1, holding promise in all relevant technologies.
研究领域:
微生物学
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环境工程
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能源技术
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生物技术
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DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
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IF 8.1
Haoran Tian,Qingyu Wu,Qiuju Wu,Chengyou Sun,Ruimei Zhang,Jie Wei,Haiyin Xu,Zhiming Liu,Chao Huang,Ping Wang
Nano zero-valent iron (nZVI) has been widely employed for the elimination of heavy metals from wastewater. However, the practical application of nZVI is greatly limited due to its fast aggregation and surface passivation. In this study, a carbon nanotube-supported nZVI composite (nZVI@CNTs) was synthesized and coupled with Shewanella oneidensis MR-1 to enhance the removal of Cr(VI) from aqueous media. The results demonstrated that the coupling of nZVI@CNTs and MR-1 (nZVI@CNTs/MR-1) exhibited superior performance in eliminating Cr(VI) compared to using nZVI@CNTs or MR-1 alone. Electrochemical characterization demonstrated that CNTs acting as electron shuttles improve the electron transfer from MR-1 to nZVI, thus facilitating the passivation layer dissolution. XRD analysis proved that MR-1 can effectively promote the dissolution of the Fe(III) passivation layer with the existence of CNTs. FTIR and XPS analyses confirmed that CNTs contain many functional groups (such as C − C and C = O) related to extracellular electron transfer, thus promoting the electron transfer of MR-1 to nZVI. Three-dimensional excitation-emission matrix (3D-EEM) analysis showed that the extracellular polymeric substances (EPS) generated from MR-1 participated in the Cr(VI) elimination. The mechanism analysis demonstrated the Fe(II) dissolved from the nZVI passivation layer reduces Cr(VI) to Cr(III) and then removes it by co-precipitation, and the EPS secreted by MR-1 also participates in the Cr(VI) adsorption and reduction. Generally, the coupling of nZVI@CNTs and MR-1 successfully addresses the drawbacks of nZVI and demonstrates a remarkable ability to remove Cr(VI).
研究领域:
环境科学
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微生物学
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2023
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IF 13.6
Fuyu Xie,Qingke Yuan,Yukang Qie,Ying Meng,Fubo Luan
Methylmercury (MeHg) uptake by demethylating bacteria and inorganic divalent mercury [Hg(II)] uptake by methylating bacteria have been extensively investigated because uptake is the initial step of the intracellular Hg transformation. However, MeHg and Hg(II) uptake by non-methylating/non-demethylating bacteria is overlooked, which may play an important role in the biogeochemical cycling of mercury concerning their ubiquitous presence in the environment. Here we report that Shewanella oneidensis MR-1, a model strain of non-methylating/non-demethylating bacteria, can take up and immobilize MeHg and Hg(II) rapidly without intracellular transformation. In addition, when taken up into MR-1 cells, the intracellular MeHg and Hg(II) were proved to be hardly exported over time. In contrast, adsorbed mercury on cell surface was observed to be easily desorbed or remobilized. Moreover, inactivated MR-1 cells (starved and CCCP-treated) were still capable of taking up nonnegligible amounts of MeHg and Hg(II) over an extended period in the absence and presence of cysteine, suggesting that active metabolism may be not required for both MeHg and Hg(II) uptake. Our results provide an improved understanding of divalent mercury uptake by non-methylating/non-demethylating bacteria and highlight the possible broader involvement of these bacteria in mercury cycling in natural environments.
研究领域:
微生物学
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环境科学
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PubMed
高影响因子
CHEMOSPHERE
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2024
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IF 8.1
Cheng Yu,Yassine Riahi,Qian Wang,Mengyang Feng,Abdelkader Mohamed,Ke Dai,Peng Cai,Qiaoyun Huang
Persistent free radicals (PFRs) in biochar are an important electron shuttle for mediating electron transfer, which has significant impact on the biogeochemical redox reactions. Although the influence of biochar on the extracellular electron transfer (EET) for redox cycle has been extensively studied, the molecular mechanism for promoting the EET with PFRs remains poorly understood. This study investigated the oxygen-centered PFRs-mediated Cr(VI) reduction by Shewanella oneidensis MR-1 (MR-1) and exhibited the molecular mechanism of electron transfer between flavin substances and PFRs. Results showed that the Cr(VI) bioreduction rate by MR-1 increased from 31% to 70% with the addition of biochar. Electrochemical results illustrated that biochar increased biocurrent generation in the Cr(VI) bioreduction process. 3D-EEM and LC/MS spectra indicated that MR-1 secreted the flavin mononucleotide (FMN) reductase that relied on the [H] to provide the electrons. Electron paramagnetic resonance spectra illustrated that PFRs in biochar accepted the electrons from FMN reductase and stored those bioelectrons. Because of the oxidation of FMN, the electron transfer from FMN reductase to PFRs would increase the intracellular reactive oxygen species, which further produced the extracellular ·O 2 − . The reduced PFRs released the bioelectrons, accelerating the Cr(VI) reduction by ·O 2 − . Together with the results of the mutant strains experiment, it was found that the EET by c -cytochrome and free radicals contributed to the Cr(VI) bioreduction by 7.1% and 92.9%, respectively. These findings revealed that the PFRs could participate in the EET process and promote the redox reactions, providing a new approach for enhancing the remediation of heavy metal pollution by microorganisms and suggesting the important role of PFRs in the electron transfer process.
研究领域:
环境生物学
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微生物学
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电化学
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PubMed
高影响因子
iScience
·
2025
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IF 4.1
Li Yanhong,Zhao Zikang,Zhao Yao,Tang Shen,Zhang Lihao,Zhang Jie,Peng Yuqing
The overuse of antibiotics poses critical threats to environmental and human health. This study developed a constructed wetland-microbial fuel cell (CW-MFC) system integrated with pre-acclimated Shewanella oneidensis MR-1 to enhance ofloxacin (OFL) removal from wastewater. The CW-MFC demonstrated exceptional removal efficiency (>96%) for OFL across tested concentration gradients, significantly outperforming conventional constructed wetlands (CW) in both antibiotic elimination and conventional pollutant reduction. Microbial community analysis revealed that S. oneidensis MR-1 inoculation enhanced microbial diversity under OFL stress while promoting enrichment of electroactive Firmicutes phylum members compared to non-inoculated systems. The synergistic integration of bioelectrochemical processes and microbial consortia modification in CW-MFCs effectively addressed antibiotic contamination challenges. These findings establish CW-MFC technology combined with electroactive bacteria acclimation as a sustainable solution for pharmaceutical wastewater treatment, providing critical insights for optimizing antibiotic removal strategies in engineered ecosystems.
研究领域:
环境科学
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微生物学
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生态工程
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DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2018
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IF 4.61
Rong Chen,Hui Liu,Man Tong,Lei Zhao,Peng Zhang,Deng Liu,Songhu Yuan
The interplay of Fe(II) oxidation and Fe(III) bio-reduction occurs widely in both natural and engineered redox-dynamic systems. This study aimed to unravel the impact of Fe(II) oxidation by O 2 in the presence of iron-reducing bacteria on subsequent Fe(III) bio-reduction. Mixed solutions of Fe 2+ (0.1–0.5 mM) and Shewanella oneidensis strain MR-1 (MR-1, 2.0 × 10 7 CFU/mL) at neutral pH were first exposed to laboratory air for Fe(II) oxidation and bacterial inactivation, and then the resultant Fe(III) suspensions were switched to anoxic conditions for bio-reduction by the surviving bacteria. In the oxidation step, the coexisting MR-1 was inactivated by 0.8–1.71 orders of magnitude within 60 min. In the subsequent bio-reduction step, the resultant Fe(III) was bio-reduced by the surviving MR-1. Bio-reduction of the resultant Fe(III) by the surviving MR-1 was 1.8–2.5 times faster than that of the Fe(III) that was produced from Fe 2+ oxidation without MR-1 by fresh MR-1 cells at 2.0 × 10 7 CFU/mL. Although MR-1 inactivation during Fe(II) oxidation may inhibit Fe(III) bio-reduction, the increase in bio-availability of the resultant Fe(III) and the residual reactivity of dead cells led to net enhancement of bio-reduction under the tested conditions. Lepidocrocite was the sole Fe(III) mineral that was produced from Fe 2+ oxidation without MR-1, while 19% ferrihydrite was produced from Fe 2+ oxidation in the presence of MR-1. The formation of low-crystallinity ferrihydrite accounts for the increase in bio-availability of the Fe(III) minerals. The findings of this study highlight an important but overlooked impact underlying the interplay of Fe(II) oxidation and Fe(III) bio-reduction.
研究领域:
微生物学
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环境科学
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DOI
PubMed
高影响因子
JOURNAL OF POWER SOURCES
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2024
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IF 8.1
Dan Yuan,Shungang Wan,Yong Xiao,Lei Sun
This study involves the construction of an “inside-out” electronic network channel with in-situ formation of biogenic FeS (bio-FeS) nanoparticles in cells of Shewanella oneidensis MR-1 ( S . oneidensis MR-1) and a coating of conductive polypyrrole (PPy) on the outer surface of entire cells. The microbial fuel cell driven by bio-FeS and PPy co-modified S . oneidensis MR-1 (FeS/PPy@MR-1) has a maximum power density 3.6 times higher than that of the native strain. Electrochemical analysis demonstrates that the modifications of bio-FeS and PPy markedly enhance the direct electron transfer and c -type cytochrome-bound flavin-mediated single-electron reaction pathways and expand the electron output flux. The electron-donating ability of FeS/PPy@MR-1 is 7 times greater than that of the native strain. Bio-FeS and PPy can mediate novel intra/extracellular transmembrane electron transport pathways independent of the traditional respiratory chain, bridge spatially discrete redox environments, and optimize electron transfer pathways to intracellular to extracellular transfer electrons rapidly and maximally. These findings provide insights into conductive nanomaterial-mediated intra/extracellular transmembrane electron transfer, which is critical for the environment and bioenergy fields.
研究领域:
环境科学
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生物能源
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微生物学
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2022
·
IF 14.224
Cheng Yu,Xiaoxi Zhu,Abdelkader Mohamed,Ke Dai,Peng Cai,Shilin Liu,Qiaoyun Huang,Baoshan Xing
Biochar can act as a shuttle to accelerate the extracellular electron transfer (EET) by exoelectrogens. However, it is poorly understood how the persistent free radicals (PFRs) in biochar affected EET and the redox reaction. Herein, the effects of the biochar and chitosan modified biochar (CBC) on the Cr(VI) bioreduction by Shewanella oneidensis MR-1 (MR-1) was investigated. Kinetic study indicated that the Cr(VI) bioreduction rate constant by MR-1 was increased by 1.8–33.7 folds in the presence of biochar, and by 2.7–60.2 folds in the presence of CBC, respectively. Moreover, Cr(VI) bioreduction rates increased with the decreasing pH. Results suggested that the electrostatic attraction between Cr(VI) and redox-active particles could accelerate the EET by c -cytochrome due to the promotion of the Cr(VI) migration from aqueous phase to biochar or CBC. Electron paramagnetic resonance analysis suggested that the PFRs affected the electron transfer from the ·O 2 - generated by MR-1 to Cr(VI) and accelerate the Cr(VI) bioreduction. Remarkably, in the presence of PFRs, this electron shuttling process was dependent on the non-metal-reducing respiratory pathway. Our results offer new insights that free radicals may be widely involved in the EET and strongly impact on the redox reaction in the environment.
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
ENVIRONMENTAL RESEARCH
·
2022
·
IF 8.431
Boyu Jia,Tianbao Liu,Juanjuan Wan,Andrei Ivanets,Yujia Xiang,Lijuan Zhang,Xintai Su
Microbial reduction of hexavalent chromium (Cr (VI)) shows better efficiency and cost-effectiveness. However, immobilization of Cr (III) remains a challenge as there is a limited supply of electron donors. A greener and cleaner option for donating external electrons was using bioelectrochemical systems to perform the microbial reduction of Cr(VI). In this system, we constructed a polydopamine (PDA) decorated Shewanella oneidensis MR-1 ( S. oneidensis MR-1) bioelectrode with bidirectional electron transport, abbreviated as PDA@ S. oneidensis MR-1. The conjugated PDA distributed on the intracellular and extracellular of individual S. oneidensis MR-1 has been shown to accelerate electron transfer by outer membrane C-type cytochromes and flavin-bound MtrC/OmcA pathway by various electrochemical analyses. As expected, the PDA@ S. oneidensis MR-1 biofilm achieved 88.1% Cr (VI) removal efficiency (RE) and 58.1% Cr (III) immobilization efficiency (IE) within 24 h under the autotrophic conditions at the optimal voltage (−150 mV) compared with the control potential (0 mV). The PDA@ S. oneidensis MR-1 biofilm showed increased RE activity was attributed to the shortening of the distance between individual bacteria by PDA. This research provides a viable strategy for in situ bioremediation of Cr(VI) polluted aquatic environment.
研究领域:
环境微生物学
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生物修复
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电化学
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DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2026
·Vol. 14
·期 3
·122561
·
IF 7.5
Lei Wang,Yudong Li,Dongle Cheng,Jian Zhang,Huu Hao Ngo,Wenshan Guo,Jie Li,Huaqing Liu,Yanlong Wang,Aiyun Guo
Antibiotic residues persist in waters and require effective, low-chemical remediation strategies. Here we create a contacted system that brings Shewanella oneidensis (MR-1) into controlled association with nitrogen doped magnetic biochar to promote interfacial electron transfer. In a mixed tetracycline-ciprofloxacin matrix, the contacted system was superior to the single biochar or microbial system. Meanwhile, the MR-1 activity was maintained within the range of 3–20 mg/L and pH 5–8, with the best performance near pH 5-6. Electrochemical and spectroscopic signatures are consistent with interfacial electron transfer from MR-1 to surface Fe centers, accompanied by Fe 3 ⁺/Fe 2 ⁺ redox cycling and coupling of adsorption with reduction. Dissolved Fe 2+ after reaction followed similar trends and increased with carrier loading, and excitation-emission matrices showed humic-like extracellular polymers that may assist electron shuttling. Electronic-structure analysis is consistent with the observed differences between tetracycline and ciprofloxacin, with tetracycline more readily accepting the first electron at chelating diketone sites, whereas the fluorinated moiety and associated bond stability may constrain ciprofloxacin conversion. Overall, the results suggest an interface-controlled route to antibiotic co-removal under mild conditions and provide design insights linking pollutant electronics, Fe site density, and operating pH to interfacial electron flow.
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DOI
高影响因子
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