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
✓ 已验证
产品关联
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
·
微生物学
✓ 已验证
DOI
PubMed
高影响因子
Gels
·
2024
·Vol. 10
·期 8
·502
·
IF 5
Xiong Li,Chuyi Li,Yizhou Liu,Gang Han,Congyu Lin,Xiaoli Chen,Jian Mao
Carrageenans were widely utilized as thickening and gelling agents in the food and cosmetic industries, and their oligosaccharides have been proven to possess enhanced physicochemical and biological properties. In this study,Shewanella sp.LE8 was utilized for the depolymerization of κ-, ι-, and λ-carrageenan under conditions of fermentation. During a 24-h fermentation at 28 °C, the apparent viscosity of κ-, ι-, and λ-carrageenan decreased by 53.12%, 84.10%, and 59.33%, respectively, accompanied by a decrease in storage modulus, and loss modulus. After a 72-h fermentation, the analysis of methylene blue and molecular weight distribution revealed that ι-carrageenan was extensively depolymerized into smaller polysaccharides byShewanella sp.LE8, while exhibiting partial degradation on κ- and λ-carrageenan. However, the impact ofShewanella sp.LE8 on total sugars was found to be limited; nevertheless, a significant increase in reduced sugar content was observed. The ESIMS analysis results revealed that the purified components obtained through ι-carrageenan fermentation for 72 h were identified as tetrasaccharides, while the two purified components derived from λ-carrageenan fermentation consisted of a hexasaccharide and a tetrasaccharide, respectively. Overall, the present study first reported the depolymerization of ι-and λ-carrageenan byShewanellaand suggested that theShewanellacould be used to depolymerize multiple carrageenans, as well as complex polysaccharides derived from red algae, to further obtain their oligosaccharides.
研究领域:
食品科学
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生物化学
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产品关联
DOI
PubMed
高影响因子
CORROSION SCIENCE
·
2024
·
IF 7.4
Xiangping Hao,Yixin Qian,Yun Bai,Ning Wang,Hongchang Qian,Yuntian Lou,Luning Wang,Dawei Zhang
This study reports the effect of extracellular electron transfer (EET) on biomineralization mediated by Shewanella putrefaciens in damaged coatings under different carbon source conditions. S. putrefaciens was able to obtain energy from metal surfaces to support metabolism via EET when the carbon source was insufficient. Under these conditions, bacteria colonized the coating scratches, resulting in accelerated corrosion instead of mineralization. The EIS results revealed that biomineralization was most significant in the 75% carbon source medium after 7 days of incubation. Interestingly, the pH of the medium increased with an abundance of carbon sources, which promoted biomineralization.
研究领域:
微生物学
·
材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
ACS ES&T Water
·
2020
·
IF 0
Mingyue Zhao,Zhicheng Cui,Liang Fu,Fabrice Ndayisenga,Dandan Zhou
The slow reduction of Fe(III) to Fe(II) in electro-Fenton technology limits pollutant removal and causes Fe sludge production. This study hypothesizes that Shewanella, a dissimilatory iron-reducing bacteria, can accelerate the iron reduction of the Fenton reaction. A Shewanella biofilm coupled with Fe2O3 coated electrode (F/S) was used to drive the electro-Fenton reaction, and compared the results with the singlet Fe2O3 (F) anode and Shewanella biofilm anode (S). Meanwhile, dissolved oxygen (DO) is studied as an important influencing factor. The suitable DO was verified at ∼2 mg/L, phenol removal of F/S was 67% higher than that of the sum of three other singlet systems. The chemical oxygen demand (COD) removal was 72% and 50% higher than that of F and S, respectively. F/S corrosion current (Icorr) was 6.3 times higher than F, and induced hematite to transform into Fe2PO5 and FeOOH on the anode. Long-term operation showed that phenol was almost 100% removed for F/S; COD removal was generally 20% higher than F; thus, the toxicity of the effluent could be significantly decreased. The total Fe loss did not exceed 10% at the end of operation. This paper provides a feasibly novel method for electro-Fenton reaction, by employing Fe-reducing bacteria.
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
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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产品关联
DOI
高影响因子
BIORESOURCE TECHNOLOGY
·
2015
·
IF 4.494
Jiexun Huang,Guojing Ning,Feili Li,G. Daniel Sheng
Anaerobic transformation of 2,4-DNT by obligate marine Shewanella marisflavi EP1 was investigated. The cell growth of EP1 was proportional to the total amount of 2,4-DNT reduced. The eventual transformation product was 2,4-diaminotoluene, via 2-amino-4-nitrotoluene and 4-amino-2-nitrotoluene as intermediates. The presence of Cu 2+ , dicumarol, metyrapone and flavins intensively influenced the reduction activity of 2,4-DNT, suggesting that dehydrogenease, menaquinone, cytochromes and flavins are essentially involved in electron transport process for 2,4-DNT reduction. These results indicate that biotransformation of 2,4-DNT by EP1 is a form of microbial anaerobic respiration. Furthermore, EP1 was capable of transforming 2,4-DNT at relatively alkaline range of pH (7–9), and at a wide range of temperature (4–40 °C) and salinity (2–8% NaCl concentration). Our findings not only deepen our understanding of the environmental fate of 2,4-DNT, but also provide an extension to the application of shewanellae in the site bioremediation and/or wastewater treatment.
研究领域:
环境科学
·
微生物学
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产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Xiong Li,Chuyi Li,Wanzi Yao,Jian Mao
Carrageenan oligosaccharides have attracted significant attention due to their excellent biological activities, and they can be produced by carrageenases. In this study, a novel marine bacterium, Shewanella sp. LE8, was used to enzymatically degrade carrageenan, and the κ-, ι-, and λ-carrageenases produced by the bacterium were characterized. The crude enzyme derived from media exhibited κ-carrageenase activity, indicating its natural secretion during growth and proliferation. According to the results of molecular weight distribution from HPGPC, λ-carrageenan could be degraded by Shewanella sp. LE8 cells in both 20 mM Tris-HCl buffer and PBS, while ι-carrageenan can only be hydrolyzed in PBS environment, indicating the activation of ι-carrageenase in Shewanella sp. LE8 was dependent on the presence of Na + ions. The components of carrageenan hydrolysates were determined by ESIMS, and results revealed that κ-carrageenan hydrolysates were primarily consisted of G4S-DA, [G4S-DA] 2 and [G4S-DA] 3 , while ι-carrageenan hydrolysates were predominantly composed of [G4S-DA2S] 2 . Moreover, the fragment ions of λ-carrageenan revealed that the hydrolytic process not only encompasses enzymatic cleavage of glycosidic bonds but also involves the participation of sulfatase. The precise structure was further elucidated through NMR analysis, confirming that the end-products of ι-carrageenase were neoι-carratetraose. The results highlight the potential of Shewanella sp. LE8 for industrial applications in the production of ι-carrageenan oligosaccharides.
研究领域:
海洋生物学
·
酶学
·
生物化学
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产品关联
DOI
PubMed
高影响因子
Journal of Environmental Sciences
·
2021
·
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
·
污染治理
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产品关联
DOI
PubMed
高影响因子
Environmental Science-Nano
·
2017
·Vol. 4
·期 12
·2395-2404
·
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
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
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
·
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
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）