PROCESS BIOCHEMISTRY
·
2023
·
IF 4.4
Xiaoxue Zhang,Mengmeng Zhong,Rui Zhou,Wenxiu Qin,Youbin Si
Microbial reduction of Se(IV) to Se(0) is extremely important for the detoxification of selenium oxyanion, but the reductive mechanism is still controversial. In this study, the reduction of Se(IV) by Shewanella oneidensis MR-1 and Shewanella putrefaciens was systematically investigated. The results showed that excessive Se(IV) severely inhibited the growth of microorganisms and Se(IV) reduction. The extracellular accumulation of Nano-Se(0) particles was shown to be approximately 250–650 nm in diameter. Riboflavin facilitated Se(IV) reduction, while rotenone , as an electron inhibitor, could completely inhibit Se(IV) reduction, validating the extracellular electron transport process for biosynthesized Nano-Se(0). Importantly, the amorphous Nano-Se(0) synthesized by S. oneidensis MR-1 were mixtures of helical chains and Se 8 rings, while those synthesized by S. putrefaciens were mainly composed of helical chains. FTIR results demonstrated that Nano-Se(0) particles were wrapped by some proteins, organic substances and lipids , exhibiting superior dispersibility and biocompatibility. Biogenic Nano-Se(0) particles can also be considered for technological applications in various fields.
研究领域:
微生物学
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环境科学
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DOI
高影响因子
Environmental Science & Technology Letters
·
2017
·
IF 5.308
Jun-Cheng Han,Guo-Jun Chen,Li-Ping Qin,Yang Mu
Cr isotope fractionation during microbial reduction processes is commonly recognized as a promising tool in biogeochemistry and bioremediation. However, the mechanism of Cr isotope fractionation during microbial reduction is poorly understood. In this work, the relationship between the bacterial respiratory pathway and Cr isotope fractionation was investigated in Shewanella oneidensis MR-1. For comparison with the wild type, a mutant strain (ΔomcA/ΔmtrC) with a deficiency in extracellular Cr(VI) reduction was constructed by deleting the omcA and mtrC genes, which encode the terminal reductase during extracellular reduction. The magnitudes of Cr isotope fractionation (ε) for Cr(VI) reduction by the wild type and ΔomcA/ΔmtrC were −2.42 ± 0.68‰ and −2.70 ± 0.22‰, respectively. Surprisingly, the ε values were not significantly different between the two strains. This suggests that isotope fractionation is independent of the metal respiratory pathway during Cr(VI) reduction by S. oneidensis MR-1. Moreover, a three-step Cr isotope fractionation model that includes uptake, reduction, and efflux was proposed to exist during intracellular Cr(VI) reduction by S. oneidensis MR-1. The developed model provides a better understanding of Cr isotope fractionation during microbial reduction.
研究领域:
生物地球化学
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环境微生物学
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DOI
高影响因子
BIODEGRADATION
·
2018
·Vol. 29
·期 2
·129-140
·
IF 2.41
Mao Fei,Liu Xiaohong,Wu Kang,Zhou Chen,Si Youbin
Because of extensive sulfonamides application in aquaculture and animal husbandry and the consequent increase in sulfonamides discharged into the environment, strategies to remediate sulfonamide-contaminated environments are essential. In this study, the resistance of Shewanella oneidensis MR-1 and Shewanella sp. strain MR-4 to the sulfonamides sulfapyridine (SPY) and sulfamethoxazole (SMX) were determined, and sulfonamides degradation by these strains was assessed. Shewanella oneidensis MR-1 and Shewanella sp. strain MR-4 were resistant to SPY and SMX concentrations as high as 60 mg/L. After incubation for 5 days, 23.91 ± 1.80 and 23.43 ± 2.98% of SPY and 59.88 ± 1.23 and 63.89 ± 3.09% of SMX contained in the medium were degraded by S. oneidensis MR-1 and Shewanella sp. strain MR-4, respectively. The effects of the initial concentration of the sulfonamides and initial pH of the medium on biodegradation, and the degradation of different sulfonamides were assessed. The products were measured by LC–MS; with SPY as a substrate, 2-AP (2-aminopyridine) was the main stable metabolite, and with SMX as a substrate, 3A5MI (3-amino-5-methyl-isoxazole) was the main stable metabolite. The co-occurrence of 2-AP or 3A5MI and 4-aminobenzenesulfonic acid suggests that the initial step in the biodegradation of the two sulfonamides is S–N bond cleavage. These results suggest that S. oneidensis MR-1 and Shewanella sp. strain MR-4 are potential bacterial resources for biodegrading sulfonamides and therefore bioremediation of sulfonamide-polluted environments.
研究领域:
环境科学
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微生物学
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DOI
PubMed
高影响因子
Journal of Environmental Sciences
·
2021
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IF 5.565
Cholnam Ri,Jingchun Tang,Feng Liu,Honghong Lyu,Fengxiang Li
Biochar, carbonaceous material produced from biomass pyrolysis, has been demonstrated to have electron transfer property (associated with redox active groups and multi condensed aromatic moiety), and to be also involved in biogeochemical redox reactions. In this study, the enhanced removal of Cr(VI) by Shewanella oneidensis MR-1(MR-1) in the presence of biochars with different pyrolysis temperatures (300 to 800 °C) was investigated to understand how biochar interacts with Cr(VI) reducing bacteria under anaerobic condition. The promotion effects of biochar (as high as 1.07~1.47 fold) were discovered in this process, of which the synergistic effect of BMBC700(ball milled biochar) and BMBC800 with MR-1 was noticeable, in contrast, the synergistic effect of BMBCs (300–600 °C) with MR-1 was not recognized. The more enhanced removal effect was observed with the increase of BMBC dosage for BMBC700+MR-1 group. The conductivity and conjugated O-containing functional groups of BMBC700 particles themselves has been proposed to become a dominant factor for the synergistic action with this strain. And, the smallest negative Zeta potential of BMBC700 and BMBC800 is thought to favor decreasing the distance from microbe than other BMBCs. The results are expected to provide some technical considerations and scientific insight for the optimization of bioreduction by useful microbes combining with biochar composites to be newly developed.
研究领域:
环境微生物学
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污染治理
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DOI
PubMed
高影响因子
Environmental Science-Nano
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2017
·Vol. 4
·期 12
·2395-2404
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IF 6.047
Hong-Wei Luo,Xin Zhang,Jie-Jie Chen,Han-Qing Yu,Guo-Ping Sheng
Although the existence of Fe(III) (hydr)oxide nanoparticles (NPs) in natural environments has been recently recognized, their migration and transformation, which are substantially affected by the microbial reduction process, remain unclear. In this study, hematite bioreduction and magnetite formation induced by Shewanella oneidensis MR-1, a typical metal-reducing bacterial strain, were investigated using an integrated approach that combined experiments and computational simulations at the molecular scale. High-resolution transmission electron microscopy coupled with selected area electron diffraction (SAED), Raman spectroscopy and magnetic property analyses confirmed the biogenic magnetite formation. The electron paramagnetic resonance (EPR) spectra show a decay of the EPR intensity with incubation time, implying that the biotransformation of hematite to magnetite led to concurrent changes in their contents and local structures. X-ray absorption fine spectroscopy (XAFS) identified a time-resolved structural evolution of Fe(II)/Fe(III) coordination. The octahedral configuration upon Fe(II) production was subsequently validated by DFT calculations. Microbial reductive dissolution provided various intermediate states and new chemical environments regarding Fe(II)/Fe(III) complexes, such as monodentate and bidentate coordination patterns. Bioreduction caused the breakage of iron–oxygen bonds in hematite and the concomitant formation of Fe complexing microstructures for biogenic magnetite production. All these findings reveal the underlying mechanisms for the biotransformation of Fe minerals at the molecular scale and may allow us to better understand the speciation, immobilization and bioavailability of hematite NPs in natural systems.
研究领域:
微生物学
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环境科学
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材料科学
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2022
·
IF 9.136
Ling Xiong,Liying Ma,Meiqi Zhao,Haojian Zhang,Shaohua Chen
In present work, nanoscale zero-valent iron (nZVI) was successfully stabilized using fulvic acid (nZVI-FA). Shewanella oneidensis MR-1 (MR-1) was used to enhance the reactivity of the nZVI-FA. The results demonstrated that nZVI-FA combined with the MR-1 (nZVI-FA/MR-1) system could effectively solve the aggregation and surface passivation of nZVI, thereby significantly enhancing the reactivity of nZVI for Cr(VI) removal. The Cr(VI) removal efficiency of the nZVI-FA/MR-1 system (100 %) within 24 h was apparently higher than that of the ZVI-FA system (64.43 %). The enhancement of Cr(VI) removal is because fulvic acid (FA) FA can stabilize nZVI against aggregation; MR-1 could rapidly reduce the Fe(III) (hydr)oxides (FeHOs) passivation layers on the surface of nZVI-FA to biogenic Fe(II) [bio-Fe(II)], which in turn reduced Cr(VI). X-ray photoelectron spectroscopy (XPS) analysis revealed that the Fe(II)/Fe(III) ratio (1.20) and Cr(III)/Cr(VI) ratio (2.53) of the precipitates in the nZVI-FA/MR-1 system were much higher than that those in the nZVI-FA system (0.55 and 1.40, respectively). Three-dimensional excitation-emission matrix (3D-EEM) spectral analysis confirmed that tyrosine, tryptophan, and protein-like substances in extracellular polymeric substances (EPSs) from MR-1 are vital for the removal of Cr(VI). The mechanism analysis demonstrated that most Cr(VI) was reduced to Cr(III); Cr(III) existed as Cr 2 O 3 , FeCr 2 O 4 and Cr x Fe 1-x (OH) 3 precipitates, and some of the Cr(VI) was removed from the solution by adsorption and complexation. This study offers a low-cost, efficient, and environmentally friendly strategy to enhance the reactivity of nZVI for Cr(VI) removal, which has broad prospective applications.
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
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2020
·Vol. 27
·期 14
·16745-16753
·
IF 3.056
Yu Cheng,Zhang Yi,Fang Yu,Tan Yujie,Dai Ke,Liu Shilin,Huang Qiaoyun
Shewanella oneidensis MR-1 (MR-1)-impregnated alginate capsules with 3D porous structure were prepared through cation crossing-linking and was used for the Cr(VI) reduction and removal. After being encapsulated by alginate, the endurance of the MR-1 was largely enhanced under conditions of high Cr(VI) concentrations (up to 4 mM) and low pH (pH 5). The Cr(VI) reduction over the MR-1-impregnated alginate capsules could be fitted by pseudo first-order kinetic model. With the Cr(VI) initial concentration increasing from 1 to 4 mM, the first-order rate constant for the encapsulated MR-1 ( k capsules ) and free cells ( k cells ) fell by 26.3% and 82.4%, respectively. At pH 5, the k capsules value was 0.19 h − 1 , which was about 3.7 times higher than k cells . Moreover, the encapsulated MR-1 held 90.5% of the Cr(VI) reduction ability after 15 days of resting time, while the free MR-1 held 19.7%. After bioreduction, 73.6% of total chromium was adsorbed on the MR-1 impregnated Ca-alginate capsules. XPS results showed 85% of the adsorbed chromium was Cr(III). The mechanism for chromium removal over the MR-1-impregnated Ca-alginate capsules was proposed with the following steps: (1) Cr(VI) was bioreduced via the encapsulated MR-1; (2) the reduced soluble Cr(III) was adsorbed by alginate selectively. In the study, the Ca-alginate shell of the cabbage-like MR-1 impregnated capsules could be a shelter for encapsulated MR-1 to endure unfavorable conditions (e.g., low pH and high concentration of Cr(VI)) and immobilize the soluble chromium. Considering the obtained capsules derived from biomolecules were environment-friendly, the MR-1-impregnated Ca-alginate capsules were potential for the application in the remediation of environmental pollution.
Graphical abstract
研究领域:
环境科学
·
微生物学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Lv Xi,Xu Xincheng,Peng Yang,Li Bolin,Yang Lie,He Xiaoman
This study introduces a novel modification method for micron-sized zero-valent iron, utilizing Shewanella oneidensis MR-1 to simultaneously colonize its surface, disrupt the passivation layer, and alter the crystal structure of the core. This process yields a composite that retains its reducing activity even in high concentrations of pollutants (500 ppm Cr(VI)) and under neutral to slightly acidic conditions. Our findings indicate that the modified system induces the Kirkendall effect in zero-valent iron, leading to the formation of amorphous zero-valent iron with a non-spherical core structure, in contrast to conventional direct mixing approaches. The modified system achieves complete reduction of 100 ppm Cr(VI) to Cr(III) within 8 h. Notably, within the first 4 h of reaction, the reduction rate is approximately three times higher than that of the conventional direct mixing system. XPS, XRD, SEM, EEM and TEM analyses reveal that the surface passivation layer of the biochemically modified zero-valent iron is disrupted, leading to changes in its crystal structure, the formation of hollow spherical structures, and the development of a biological protective film on its surface. Interestingly, electrochemical and ETSA analyses indicate that the electron transfer rate of the biochemically modified composite is significantly enhanced. This study provides fundamental insights into the removal of Cr(VI) from groundwater using biochemically modified micron-sized zero-valent iron (mZVI).
研究领域:
环境科学
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微生物学
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产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2021
·
IF 7.963
Yunfei Zhang,Qiang Zhao,Baoliang Chen
In materials science, “green” synthesis has gotten a lot of interest as a reliable, long-lasting, and ecofriendly way to make a variety of materials/nanomaterials, including metal/metal oxide nanomaterials . To accommodate various biological materials, green synthesis of metallic nanoparticles has been used (e.g., bacteria, fungi, algae, and plant extracts). In this work, Shewanella oneidensis MR-1 was used to biosynthesize palladium nanoparticles (bio Pd) under aerobic conditions for the Cr(VI) bio-reduction. The size and distribution of bio-Pd are controlled by adjusting the ratio of microbial biomass and palladium precursors. The high cell: Pd ratio has the smallest average particle size of 6.33 ± 1.69 nm. And it has the lowest electrocatalytic potential (−0.132 V) for the oxidation of formic acid , which is 0.158 V lower than commercial Pd/C (5%). Our results revealed that the small size and uniformly distributed extracellular bio-Pd could achieve completely catalytic reduction of 200 mg/L Cr(VI) solution within 10 min, while the commercial Pd/C (5%) need at least 45 min. The bio-Pd materials maintain a high reduction during five cycles. Microorganisms play an important role in the whole process, which can fully disperse palladium nanoparticles, completely reduce Cr(VI), and effectively adsorb Cr(III). This work expands our understanding and provides a reference for the design and development of efficient and green bio-Pd catalysts for environmental pollution control under simple and mild conditions.
研究领域:
环境科学
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材料科学
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微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2020
·
IF 7.864
Tongxu Liu,Xiaobo Luo,Yundang Wu,John R. Reinfelder,Xiu Yuan,Xiaomin Li,Dandan Chen,Fangbai Li
How metal-reducing bacteria transfer electrons during dissimilatory energy generation under electron acceptor-limited conditions is poorly understood. Here, we incubated the iron and manganese-reducing bacterium Shewanella oneidensis MR-1 without electron acceptors. Removal of soluble extracellular organic compounds (EOCs) dramatically retarded transfer of electrons to an experimental electron acceptor, Cr(VI), by MR-1. However, the return of either high MW (>3000 Da) or low MW (<3000 Da) soluble EOCs produced by MR-1 to washed cells restored Cr(VI) reduction though Cr(VI) reduction was fastest when both size fractions were added together. Spectral and electrochemical characterization of EOCs indicated the presence of flavins and c-type cytochromes (c-Cyts). A model of the kinetics of individual elementary reactions between cells, flavins, released c-Cyts, and Cr(VI), including the direct reduction of flavins, released c-Cyts, and Cr(VI) by cells and the indirect reduction of Cr(VI) by reduced forms of flavins and released c-Cyts, was developed. Model results suggest that released c-Cyts could act as electron mediators to accelerate electron transfer from cells to Cr(VI), and the relative contribution of this pathway was higher than that mediated by flavins. Hence, extracellular c-Cyts produced by MR-1 likely play a role in extracellular electron transfer under electron acceptor-limited conditions. These findings provide new insights into extracellular electron shuttling and the metabolic strategy of metal-reducing bacteria under electron acceptor-limited conditions.
研究领域:
微生物学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Song Lin,Tailin Wang,Zhengyu Tao,Zhenhui Li,Shangsong Li,Xiaoman Liu,Jun Liu,Xin Huang
The synergetic integration of living microorganisms and nonliving matrices into a new artificial micro-ecological system is a crucial challenge in bio-manufacturing especially towards the development of sustainable energy technology. Here we develop a way of creating a Shewanella oneidensis based conductive micro-niche to boost hydrogen production by integrating graphene, polydopamine and alginate. We reveal that both the respiratory metabolism induces localized hypoxic conditions inside the micro-niche and the wired-up extracellular electron reverses transfer pathway from the outer environment to the periplasmic hydrogenases, contributing to the enhanced hydrogen production rate which is about 12.7 folds enhancement compared with that of the free Shewanella oneidensis in solution. Significantly, the whole assembly process shows good biocompatibility, ensuring that the Shewanella oneidensis inside the micro-niche could maintain hydrogen production for 30 days. Overall, it is anticipated the hybrid integration of microorganisms and abiotic material will provide an effective strategy to modulate green biomanufacturer as well as enhance biological hydrogen production.
研究领域:
生物工程
·
可持续能源技术
·
生物技术
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产品关联
DOI
高影响因子
CHEMOSPHERE
·
2020
·
IF 5.778
Juping You,Yingying Deng,Han Chen,Jiexu Ye,Shihan Zhang,Jingkai Zhao
An exoelectrogens, Shewanella oneidensis MR-1 ( S. oneidensis MR-1), was supplied to a microbial fuel cell (MFC) to enhance the degradation of a recalcitrant organic compound, o -xylene. The experimental results revealed that, with the addition of the S. oneidensis MR-1, the o -xylene removal efficiency increased by 35–76% compared with the original MFC. The presence of the S. oneidensis MR-1 not only improved the activity of the biofilm in the bioanode but also developed the connections between the bacteria by nanowires . Therefore, the maximum power density increased from 52.1 to 92.5 mW/m 3 after the addition of the S. oneidensis MR-1. The microbial community analysis showed that adding the S. oneidensis MR-1 increased the biodiversity in bioanode. The dominant exoelectrogens shifted from Zoogloea sp., Delftia sp., Achromobacter sp., Acinetobacter sp., Chryseobacterium sp., and Stenotrophomonas sp. to Zoogloea sp., Delftia sp., Shewanella sp., Achromobacter sp., Hydrogenophaga sp., Sedimentibacter sp. and Chryseobacterium sp.. Furthermore, the cyclic voltammetry analysis showed that the outer membrane bound protein complex of OmcA–MtrCAB was involved as direct electron transfer pathway in the S. oneidensis MR-1 containing bioanode. We believed that this work is promising to provide optional strategy for efficient VOCs degradation by adjusting the microbial community in the bioanode.
研究领域:
环境科学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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