ENVIRONMENTAL POLLUTION
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2023
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IF 8.9
Siyu Zhang,Changdong Ke,Mengge Jiang,Yuancheng Li,Weilin Huang,Zhi Dang,Chuling Guo
Efficient remedies for living organisms including bacteria to counteract cadmium (Cd 2+ ) toxicity are still highly needed. Plant toxicity studies have showed that exogenous S(-II) (including hydrogen sulfide and its ionic forms, i.e., H 2 S, HS − , and S 2− ) application can effectively alleviate adverse effects of Cd stress, but whether S(-II) could mitigate bacterial Cd toxicity remains unclear. In this study, S(-II) was applied exogenously to Cd-stressed Shewanella oneidensis MR-1 and the results showed that S(-II) can significantly reactivate impaired physiological processes including growth arrest and enzymatic ferric (Fe(III) reduction inhibition. The efficacy of S(-II) treatment is negatively correlated with the concentration and time length of Cd exposure. Energy-dispersive X-ray (EDX) analysis suggested the presence of cadmium sulfide inside cells treated with S(-II). Both compared proteomic analysis and RT-qPCR showed that enzymes associated with sulfate transport, sulfur assimilation, methionine , and glutathione biosynthesis were up-regulated in both mRNA and protein levels after the treatment, indicating S(-II) may induce the biosynthesis of functional low-molecular-weight (LMW) thiols to counteract Cd toxicity. Meanwhile, the antioxidant enzymes were positively modulated by S(-II) and thus the activity of intracellular reactive oxygen species was attenuated. The study demonstrated that exogenous S(-II) can effectively alleviate Cd stress for S. oneidensis likely through inducing intracellular trapping mechanisms and modulating cellular redox status. It suggested that S(-II) may be a highly effective remedy for bacteria such as S. oneidensis under Cd-polluted environments.
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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DOI
PubMed
高影响因子
Frontiers in Microbiology
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2016
·
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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DOI
PubMed
高影响因子
Microorganisms
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2024
·Vol. 12
·期 4
·774
·
IF 4.1
Ling Wang,Ming Xue,Rui Yan,Jiawei Xue,Zhipeng Lu,Chongqing Wen
Chitin, a polymer of β-1,4-linkedN-acetylglucosamine (GlcNAc), can be degraded into valuable oligosaccharides by various chitinases. In this study, the genome ofShewanella khirikhanaJW44, displaying remarkable chitinolytic activity, was investigated to understand its chitin-degradation potential. A chitinase geneSkChi65from this strain was then cloned, expressed, and purified to characterize its enzymatic properties and substrate hydrolysis. Genome analysis showed that, of the 14 genes related to chitin utilization in JW44, six belonged to glycoside hydrolase (GH) families because of their functional domains for chitin binding and catalysis. The recombinant chitinase SkChi65, consisting of 1129 amino acids, was identified as a member of the GH18 family and possessed two chitin-binding domains with a typical motif of [A/N]KWWT[N/S/Q] and one catalytic domain with motifs of DxxDxDxE, SxGG, YxR, and [E/D]xx[V/I]. SkChi65 was heterologously expressed as an active protein of 139.95 kDa best at 37 °C with 1.0 mM isopropyl-β-d-thiogalactopyranoside induction for 6 h. Purified SkChi65 displayed high stability over the ranges of 30–50 °C and pH 5.5–8.0 with optima at 40 °C and pH 7.0. The kinetic parametersKm,Vmax, andkcatof SkChi65 towards colloidal chitin were 27.2 μM, 299.2 μMs−1, and 10,203 s−1, respectively. In addition to colloidal chitin, SkChi65 showed high activity towards glycol chitosan and crystalline chitin. After analysis by thin-layer chromatography, the main products wereN,N’-diacetylchitobiose, and GlcNAc with (GlcNAc)2–6used as substrates. Collectively, SkChi65 could exhibit both exo- and endochitinase activities towards diverse substrates, and strain JW44 has a high potential for industrial application with an excellent capacity for chitin bioconversion.
研究领域:
微生物学
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生物化学
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生物技术
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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
Nature Communications
·
2019
·Vol. 10
·期 1
·1-12
·
IF 11.878
Zhu Huawei,Meng Hengkai,Zhang Wei,Gao Haichun,Zhou Jie,Zhang Yanping,Li Yin
Microbial biophotovoltaics (BPV) offers a biological solution for renewable energy production by using photosynthetic microorganisms as light absorbers. Although abiotic engineering approaches, e.g., electrode modification and device optimization, can enhance the electrochemical communication between living cells and electrodes, the power densities of BPV are still low due to the weak exoelectrogenic activity of photosynthetic microorganisms. Here, we develop a BPV based on a d -lactate mediated microbial consortium consisting of photosynthetic cyanobacteria and exoelectrogenic Shewanella . By directing solar energy from photons to d -lactate, then to electricity, this BPV generates a power density of over 150 mW·m −2 in a temporal separation setup. Furthermore, a spatial-temporal separation setup with medium replenishment enables stable operation for over 40 days with an average power density of 135 mW·m −2 . These results demonstrate the electron flow constrained microbial consortium can facilitate electron export from photosynthetic cells and achieve an efficient and durable power output.
研究领域:
生物能工程
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微生物学
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DOI
PubMed
高影响因子
Frontiers in Microbiology
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2026
·
IF 4.5
Guolin Yang,Ling Wei,Liang Liu,Bo Mu,Tao Chen
Bioremediation of uranium-contaminated environments using native bacteria shows great promise. While Shewanella putrefaciens ( S. putrefaciens ) is a known uranium reducing bacterium, the mechanisms and adaptability of indigenous strains from uranium mine tailings remain unexplored. This study isolated a dominant indigenous strain of S. putrefaciens and employed a combined genomic and spectroscopic approach to elucidate its unique uranium fixation mechanism. Microbial diversity analysis confirmed the dominance of Shewanella in the oligotrophic and radioactive tailings. Whole-genome sequencing revealed a significant enrichment of genes related to energy metabolism and stress resistance, providing a genetic basis for its survival and activity. Crucially, by combining advanced spectroscopic techniques with an MtrA gene knockout experiment, we deciphered the specific role of the Mtr pathway in extracellular electron transfer for uranium reduction. Remarkably, the isolated strain achieved a uranium removal efficiency of up to 93% under experimental conditions, demonstrating its high potential for uranium bioremediation. This work not only provides a robust indigenous candidate for bioremediation but also delivers novel mechanistic insights into the uranium transformation processes of indigenous Shewanella , advancing strategies for the application of tailored microbiomes in radioactive waste management.
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DOI
PubMed
高影响因子
Nature Communications
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2020
·Vol. 11
·期 1
·1-11
·
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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产品关联
DOI
PubMed
高影响因子
RUSSIAN JOURNAL OF ELECTROCHEMISTRY
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2023
·Vol. 59
·期 10
·817-829
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IF 1.2
Jiaran Qi,Xu Yongjie,Chu Gang,Liu Xiaohong,Si Youbin
Abstract The widespread use of penoxsulam has increased the potential for environmental risks. In this study, a microbial fuel cell (MFC) was investigated and optimized for degradation of penoxsulam and corresponding power generation performance. Of the electricity producing bacteria tested, Shewanella putrefaciens was found to be the most suitable, and reached a maximum power of 260.4 mW/m 2 along with a penoxsulam degradation efficiency of 95%. MFC electrical performance was greatly enhanced by increasing the anode carbon felt surface area from 5 to 20 cm 2 , which raised the MFC electrical power from 90.3 to 240.3 mW/m 2 and increased the penoxsulam degradation efficiency in parallel. The initial penoxsulam concentration in the reaction system influenced MFC power generation, where higher initial penoxsulam concentrations inhibited microbial activity, decreased the MFC power performance, and reduced the penoxsulam degradation efficiency. In addition, the MFC reaction system pH influenced MFC electrical performance, and adjusting the pH to 8 increased the peak voltage and power density to 0.687 V and 264.8 mW/m 2 , respectively. S. putrefaciens secretes soluble compounds to mediate electron transfer and the addition of Riboflavin (RF) increases the charge transfer efficiency. Our findings provide a basis for revealing the mechanism by which organic contaminants are degraded in MFCs, and demonstrate the feasibility of MFCs for efficient penoxsulam degradation and power generation.
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
CARBOHYDRATE RESEARCH
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2017
·
IF 2.096
Louis Patrick Conway,Fang Fang Liu,Qian Li,Josef Voglmeir
Galactokinases are a class of enzymes which belong to the GHMP (galactokinase, homoserine kinase, mevalonate kinase , and phosphomevalonate kinase) superfamily and catalyse the phosphorylation of galactose in the first step of the Leloir pathway . Here we report the discovery of three enzymes from Shewanella woodyi which have been classified as galactokinases based on sequence similarity. However, each of these enzymes show little to no significant activity towards galactose and instead exhibit a strong preference for glucose. Furthermore, in contrast to the usual galactose-1-phosphate product of the galactokinase-catalysed reaction, these enzymes produce glucose-6-phosphate. This radical change in enzyme functionality is postulated to be linked to the mutation of a glycine residue which is conserved in all other sequenced galactokinases.
研究领域:
生物化学
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微生物学
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产品关联
DOI
PubMed
高影响因子
WATER SCIENCE AND TECHNOLOGY
·
2021
·Vol. 84
·期 4
·1037-1047
·
IF 1.915
Li Zhi,Zhao Jun,Liu Bianhua,Yang Linlin,Han Guangmei,Yang Fan,Han Shuai,Wang Zhenyang,Zhang Zhongping
Degradation of various organic pollutants by bacteria has been proved to be an economical and environmentally friendly method. The key challenge in making these technologies widely available is their low degradation efficiency. Here, we report a composite membrane composed of graphene oxide and polyvinyl alcohol (GO-PVA) which can markedly enhance the efficiency and rate of Shewanella bacteria to degrade Congo red (CR). The degradation efficiency of Shewanella bacteria alone on CR solution was about 42% at 72 h. After the addition of the GO-PVA membrane, the degradation efficiency reached 91% at the degradation time at 36 h. The degradation efficiency of CR was increased by two times and the degradation rate was increased by four times in the presence of GO-PVA membrane and Shewanella bacteria compared to Shewanella bacteria alone. This indicates that the CR could be rapidly and completely degraded by increasing the input amounts of GO-PVA membrane in the process of Shewanella algae degradation of CR. Moreover, the GO-PVA membrane showed good recyclability and reusability. The biocatalysts performance of the GO-PVA membrane did not decrease after 10 cycles. Furthermore, the role of the GO-PVA membrane in the degradation process and the degradation products of CR were discussed. The efficiency of Shewanella bacteria to degrade CR is about 42% at 72 h. The GO-PVA can significantly improve the degradation rate and efficiency of CR. The degradation rate was increased by four times and the efficiency was increased by about two times. The GO in the GO-PVA plays as a redox mediator in the degradation of CR. The GO-PVA shows good recyclability and reusability.
研究领域:
环境科学
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微生物学
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材料科学
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
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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产品关联
DOI
PubMed
高影响因子
Frontiers in Microbiology
·
2019
·
IF 4.259
Zhao Gang,Li Enze,Li Jianjun,Liu Fei,Yang Xunan,Xu Meiying
Flavin mononucleotide (FMN) and riboflavin are structurally similar flavins, except for the presence of a phosphate group on the FMN molecule. They are used by a variety of electroactive bacteria as extracellular electron shuttles in microbial Fe reduction and inevitably interact with Fe (hydr)oxides in the extracellular environment. It is currently unknown whether flavin/Fe (hydr)oxide interaction interferes with extracellular electron transfer (EET) to the mineral surface. In this study, we found that the goethite reduction rate was lower when mediated by FMN than by RF, suggesting that FMN was less effective in shuttling electrons between cells and minerals. Nevertheless, the phosphate group did not prevent the FMN molecule from accepting electrons from bacterial cells and transferring electrons to the mineral. Results of adsorption experiment, attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy, and bacterial attachment trend analyses showed that FMN exhibited strong adsorption on goethite surface by forming phosphate inner-sphere complex, which prevented bacterial cells from approaching goethite. Therefore, the interaction between FMN and goethite surface may increase the distance of electron transfer from bacterial cells to goethite and result in lower EET efficiency in comparison to those mediated by riboflavin. To our knowledge, these data reveal for the first time that the interaction between flavin and Fe (hydr)oxide affect flavin-mediated electron transfer to mineral surface and add a new dimension to our understanding of flavin-mediated microbial Fe reduction processes.
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
危险品化学品经营许可证（带存储）