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Wang Y, Huang F, Liu J, Rao X, Liu Q, Xiao R, Huang M, Li H, Bai J, Wang P, Zhou X. Ferric citrate enhanced bioreduction of Cr(VI) by Bacillus cereus RCr in aqueous solutions: reduction performance and mechanisms. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024:10.1007/s11356-024-34394-4. [PMID: 39042195 DOI: 10.1007/s11356-024-34394-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Accepted: 07/11/2024] [Indexed: 07/24/2024]
Abstract
The bioreduction characteristics and mechanisms of Cr(VI) onto Bacillus cereus RCr enhanced by ferric citrate were investigated. The optimum conditions were initial pH 9, temperature 40 °C, inoculation amount 4%, and glucose 3 g/L, respectively. The addition of 1.5 g/L ferric citrate increased the average reduction rate from 120.43 to 220.61 mg/(L∙h) compared with the control (without ferric citrate). The binding capacity of Cr(III) on the cell surface increased to 21%, in which the precipitates were mainly CrO(OH), Cr2O3, and FeCr2O4. Cell membrane was the main site of reduction, related important functional groups: - COOH, C-H, - NH2, C = C, and P-O. Fe(III) increased the yield of NADH and cytochrome c by approximately 48.51% and 68.63%, which significantly facilitated the electron generation and electron transfer, thus increasing the amount of electrons in the bioreduction of heavy metals by an average of 110%. Among the electrons obtained by Cr(VI), the proportion of indirect reduction mediated by Fe(III)/Fe(II) shuttle was 62% on average, whereas direct reduction mediated by reductase was 38%. These results may provide insights into the bioreduction process by bacteria enhanced by Fe(III) for detoxification of heavy metals with multiple valences, as an important step towards improving microbial remediation.
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Affiliation(s)
- Yishuo Wang
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, P.R. China
| | - Fei Huang
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, P.R. China.
| | - Jiaxin Liu
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, P.R. China
| | - Xin Rao
- School of Mathematics and Statistics, Guangdong University of Foreign Studies, Guangzhou, 510420, P.R. China
| | - Qianjun Liu
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, P.R. China
| | - Rongbo Xiao
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, P.R. China
| | - Mingzhi Huang
- Guangdong Provincial Engineering Research Center of Intelligent Low-Carbon Pollution Prevention and Digital Technology, South China Normal University, Guangzhou, 510006, P.R. China
- SCNU (NAN'AN) Green and Low-Carbon Innovation Center, Nan'an SCNU Institute of Green and Low-Carbon Research, Quanzhou, 362300, P.R. China
| | - Haolin Li
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, P.R. China
| | - Jinjing Bai
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, P.R. China
| | - Peng Wang
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, P.R. China
| | - Xiao Zhou
- Analysis and Test Center, Guangdong University of Technology, Guangzhou, 510006, P.R. China
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2
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Li T, Du D, Li C, Zhao J, Guo L, Wang X, Zhao J, Xiang W. Investigation on Cr(VI)-bioreduction mechanism and reduction products by a novel Microbacterium sp. strain NEAU-W11. CHEMOSPHERE 2023; 343:140232. [PMID: 37734508 DOI: 10.1016/j.chemosphere.2023.140232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 08/12/2023] [Accepted: 09/18/2023] [Indexed: 09/23/2023]
Abstract
Cr(VI) widely exists in the environment and has highly toxic, carcinogenic and mutagenic effects on all organisms. Physical/chemical methods to remove chromium pollution are economically expensive and have disadvantages like high reagent consumption, energy requirements and so on, while bioremediation is an eco-friendly, simple and cost-effective way. In this study, a novel Cr(VI)-reducing strain, Microbacterium sp. NEAU-W11, was reported, and its reduction mechanism was investigated. Microbacterium sp. NEAU-W11 could effectively degrade Cr(VI) under the conditions of pH 7-10, 15-35 °C, and the coexistence of metal pollutants such as Pb and Ni, etc. In addition, both Fe3+ and Cu2+ could improve the reducing ability of strain NEAU-W11, and glucose and lactose as electron donors also had promoting effect. Heat treatment of resting cells confirmed that chromium removal was not biological sorption but biological reduction. The active reductase of strain NEAU-W11 to chromium(VI) mainly existed in the cell cytoplasm, which is the first report in the genus Microbacterium. Micro-characterization of strain NEAU-W11 and the reduction products identified the reduction products as Cr(III)-ligand complexes bound to extracellular polymeric substances (EPS). Collectively, this study systematically investigated the degradation mechanism of Microbacterium sp. NEAU-W11 and the distribution of degradation product Cr(III), providing a new reduction mechanism for the genus Microbacterium, providing a new perspective for a comprehensive understanding of the degradation and transport of chromium by bacteria, and providing theoretical reference for the migration of metal ions in environmental governance.
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Affiliation(s)
- Tingting Li
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 59 Mucai Street, Xiangfang District, Harbin, 150030, People's Republic of China
| | - Dandan Du
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 59 Mucai Street, Xiangfang District, Harbin, 150030, People's Republic of China
| | - Chenxu Li
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 59 Mucai Street, Xiangfang District, Harbin, 150030, People's Republic of China
| | - Junlei Zhao
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 59 Mucai Street, Xiangfang District, Harbin, 150030, People's Republic of China
| | - Lifeng Guo
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 59 Mucai Street, Xiangfang District, Harbin, 150030, People's Republic of China
| | - Xiangjing Wang
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 59 Mucai Street, Xiangfang District, Harbin, 150030, People's Republic of China
| | - Junwei Zhao
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 59 Mucai Street, Xiangfang District, Harbin, 150030, People's Republic of China.
| | - Wensheng Xiang
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 59 Mucai Street, Xiangfang District, Harbin, 150030, People's Republic of China; State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
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3
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Zhao Y, Gao J, Zhou X, Li Z, Zhao C, Jia X, Ji M. Bio-immobilization and recovery of chromium using a denitrifying biofilm system: Identification of reaction zone, binding forms and end products. J Environ Sci (China) 2023; 126:70-80. [PMID: 36503795 DOI: 10.1016/j.jes.2022.03.050] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 03/29/2022] [Accepted: 03/29/2022] [Indexed: 06/17/2023]
Abstract
Chromium is an important resource in strategic metals. Different from most studies focusing on the bio-reduction of hexavalent chromium [Cr(VI)], this study aims to achieve the immobilization and recovery of chromium using a sequencing batch biofilm reactor. Results showed that Cr(VI) removal efficiency remained more than 99%, and 97% of reduced Cr(III) was immobilized in the biofilm. Immobilization zone, chromium forms and extracellular polymeric substances composition changes were combined to reveal the mechanism of Cr(VI) reduction and immobilization. The chromium distribution in biofilm demonstrated that intercellular layer was the main active zone with an immobilization amount of 891.70±126.32 mg/g-VSS. The reduced products analysis confirmed that trivalent chromium [Cr(III)] chelated with carboxyl, amino and other functional groups and immobilized in the form of organic Cr(III). The digestion method realized a chromium recovery efficiency of 74.59%. This study provides an alternative method for the bioremediation and resources recovery in chromium polluted wastewater.
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Affiliation(s)
- Yingxin Zhao
- School of environment Science and Engineering, Tianjin University, Tianjin 300350, China.
| | - Junzhi Gao
- School of environment Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Xu Zhou
- School of environment Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Zhouran Li
- School of environment Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Cailian Zhao
- School of environment Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Xulong Jia
- School of environment Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Min Ji
- School of environment Science and Engineering, Tianjin University, Tianjin 300350, China
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4
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Huang Y, Zeng Q, Hu L, Zhong H, He Z. Column study of enhanced Cr(VI) removal by bio-permeable reactive barrier constructed from novel iron-based material and Sporosarcina saromensis W5. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:44893-44905. [PMID: 35138543 DOI: 10.1007/s11356-022-18972-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 01/26/2022] [Indexed: 06/14/2023]
Abstract
In this study, the feasibility of Cr(VI) removal from synthetic groundwater by bio-permeable reactive barrier constructed from novel iron-based material (SiO2/nano-FeC2O4 composite, SNFC) and Sporosarcina saromensis W5 was investigated. According to breakthrough study, an enhanced Cr(VI) removal was found in Bio-SNFC column. The Cr(VI) removal performances of biotic column with 0.2 g biomass and 0.4 g biomass were 16.2 mg/g and 17.9 mg/g, respectively, which were 19.6% and 32.1% higher than that of abiotic column (13.5 mg/g). However, excessive biomass (0.9 g) would cause pore clogging and have a negative impact on the Cr(VI) removal performance of the biotic column, whose removal capability (29.1%) was lower than that of abiotic column. The introduction of proper microorganisms enhanced the utilization of iron and enabled a higher proportion of Fe(II) in biotic column, which provided more reactive sites for Cr(VI) removal. The solid phase characterization indicated the generation of Fe(III) oxide/hydroxide on SNFC surface. The removal of Cr(VI) in Bio-SNFC column was depended on reduction-precipitation, and the final products related to chromium were mainly Cr(OH)3 and Cr2O3. The present work provides a new and sustainable remediation technology for in situ bioremediation of Cr(VI)-contaminated groundwater.
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Affiliation(s)
- Yongji Huang
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China
| | - Qiang Zeng
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China
| | - Liang Hu
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China
| | - Hui Zhong
- School of Life Science, Central South University, Changsha, 410012, China.
| | - Zhiguo He
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China.
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5
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Xu L, Su J, Ali A, Huang T, Yang Y, Shi J, Liang E. Magnetite-loaded rice husk biochar promoted the denitrification performance of Aquabacterium sp. XL4 under low carbon to nitrogen ratio: Optimization and mechanism. BIORESOURCE TECHNOLOGY 2022; 348:126802. [PMID: 35131457 DOI: 10.1016/j.biortech.2022.126802] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 01/27/2022] [Accepted: 01/28/2022] [Indexed: 06/14/2023]
Abstract
The removal of nitrate (NO3--N) under the low carbon to nitrogen (C/N) ratio is a widespread issue. Here in, a modified biochar (MRHB) was prepared by combining rice husk and magnetite to promote the denitrification performance of Aquabacterium sp. XL4 under low C/N ratio. In addition, when the modified H2O2 concentration was 0.6 mM, the dosage was 5.0 g L-1, the C/N ratio was 1.5, and the pH was neutral, the nitrate removal efficiency is 97.9%. Fluorescence excitation-emission matrix spectra (3D-EEM) showed that the metabolism of strain XL4 was stable under optimal conditions. Furthermore, the results of flow cytometry (FC) showed that the amounts of intact cells with MRHB was excellent. The measurement of cytochrome c concentration, total membrane permeability (Tmp), electron transport system activity (ETSA), and cyclic voltammetry curve (CV) confirmed that the MRHB improved the electron transfer and membrane activity of strain XL4.
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Affiliation(s)
- Liang Xu
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Junfeng Su
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Amjad Ali
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Tinglin Huang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Yuzhu Yang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Jun Shi
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Enlei Liang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
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6
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Zarei M, Mir-Derikvand M, Hosseinpour H, Samani TR, Ghasemi R, Fatemi F. U (VI) tolerance affects Shewanella sp. RCRI7 biological responses: growth, morphology and bioreduction ability. Arch Microbiol 2021; 204:81. [PMID: 34958431 DOI: 10.1007/s00203-021-02716-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 10/30/2021] [Accepted: 11/19/2021] [Indexed: 11/27/2022]
Abstract
Native Shewanella sp. RCRI7 is recently counted as an operative bacterium in the uranium bio-reduction. The aim of this study was to investigate the effects of uranium tolerance on the morphology and population of RCRI7, following its potential removal capacity in different time intervals. In this research, the bacterial growth and uranium removal kinetic were evaluated in aerobic TSB medium, uranium-reducing condition (URC), aerobic uranium-containing (AUC) and anaerobic uranium-free (AUF) solution, following evaluations of omcAB gene expressions. In addition, spectrophotometry analyses were performed in URC confirming the bio-reduction mechanism. It was found that the bacteria can grow efficiently in the presence of 0.5 mM uranium anaerobically, unlike AUC and AUF solutions. Since the bacterium's adsorption capacity is quickly saturated, it can be deduced that uranium reduction should be dominant as incubation times proceed up to 84 h in URC. In 92 h incubation, the adsorbed uranium containing unreduced and reduced (U (IV) monomeric), was released to the solution due to either increased pH or bacterial death. In AUC and AUF, improper conditions lead to the reduced bacterial size (coccus-shape formation) and increased bacterial aggregations; however, membrane vesicles produced by the bacteria avoid the uranium incrustation in AUC. In overall, this study implies that Shewanella sp. RCRI7 are well tolerated by uranium under anaerobic conditions and the amount of regenerated uranium increases over time in the reduced form.
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Affiliation(s)
- Mahsa Zarei
- Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
| | - Mohammad Mir-Derikvand
- Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
| | | | | | - Razieh Ghasemi
- Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
| | - Faezeh Fatemi
- Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, Tehran, Iran.
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7
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Gautam A, Kushwaha A, Rani R. Reduction of Hexavalent Chromium [Cr(VI)] by Heavy Metal Tolerant Bacterium Alkalihalobacillus clausii CRA1 and Its Toxicity Assessment Through Flow Cytometry. Curr Microbiol 2021; 79:33. [PMID: 34952958 DOI: 10.1007/s00284-021-02734-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 12/03/2021] [Indexed: 12/01/2022]
Abstract
A chromate-resistant bacterial strain was isolated from tannery effluent; based on morphological, biochemical, and 16S rRNA gene sequencing, it was identified as Alkalihalobacillus clausii and designated A. clausii CRA1. It was found to be halophilic, alkaliphilic, and resistant to multiple heavy metals like Cr(VI), Cd(II), As(II), Pb(II), Ni(II), Hg(II), Cu(II), Zn(II), and Fe(II). The strain was found to reduce 72% of chromate in 6 days in Cr(VI) spiked Luria Bertani medium with unaffected bacterial growth at an initial C(VI) concentration of 50 mg L-1. Chromate reductase activity of culture supernatant (cultivated in LB broth) and cell lysate of the bacterium was found to be 23 and 43U, where 1U is µmol of Cr(VI) reduced/min/mg protein. Flow cytometry studies revealed that no significant effect of Cr(VI) on cell viability was observed till 12 h of exposure at 100, 200, 400 mg L-1 concentrations, indicated by non-significant cell death (propidium iodide positive cells). However, at 800 and 1000 mg L-1 Cr(VI) concentration, toxicity (cell death) was observed after 12 h of exposure. FACs studies also indicated that exposure to Cr(VI) increases cell size and cell granularity, which was also confirmed in SEM and TEM images of Cr(VI) treated cells. The presence of Cr(III) species in EDX spectra of Cr(VI) treated cells confirms that reduction of Cr(VI) to Cr(III) is the primary mechanism of Cr(VI) removal by the bacterium. Therefore, the bacterium A. clausii has potential for application in chromate removal from industrial waste effluents.
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Affiliation(s)
- Aishvarya Gautam
- Department of Biotechnology, Motilal Nehru National Institute of Technology Allahabad, Teliyarganj, Prayagraj, Uttar Pradesh, 211004, India
| | - Anamika Kushwaha
- Department of Biotechnology, Motilal Nehru National Institute of Technology Allahabad, Teliyarganj, Prayagraj, Uttar Pradesh, 211004, India
| | - Radha Rani
- Department of Biotechnology, Motilal Nehru National Institute of Technology Allahabad, Teliyarganj, Prayagraj, Uttar Pradesh, 211004, India.
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8
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Insights into the Biosynthesis of Nanoparticles by the Genus Shewanella. Appl Environ Microbiol 2021; 87:e0139021. [PMID: 34495739 DOI: 10.1128/aem.01390-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The exploitation of microorganisms for the fabrication of nanoparticles (NPs) has garnered considerable research interest globally. The microbiological transformation of metals and metal salts into respective NPs can be achieved under environmentally benign conditions, offering a more sustainable alternative to chemical synthesis methods. Species of the metal-reducing bacterial genus Shewanella are able to couple the oxidation of various electron donors, including lactate, pyruvate, and hydrogen, to the reduction of a wide range of metal species, resulting in biomineralization of a multitude of metal NPs. Single-metal-based NPs as well as composite materials with properties equivalent or even superior to physically and chemically produced NPs have been synthesized by a number of Shewanella species. A mechanistic understanding of electron transfer-mediated bioreduction of metals into respective NPs by Shewanella is crucial in maximizing NP yields and directing the synthesis to produce fine-tuned NPs with tailored properties. In addition, thorough investigations into the influence of process parameters controlling the biosynthesis is another focal point for optimizing the process of NP generation. Synthesis of metal-based NPs using Shewanella species offers a low-cost, eco-friendly alternative to current physiochemical methods. This article aims to shed light on the contribution of Shewanella as a model organism in the biosynthesis of a variety of NPs and critically reviews the current state of knowledge on factors controlling their synthesis, characterization, potential applications in different sectors, and future prospects.
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9
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Zhang K, Li N, Liao P, Jin Y, Li Q, Gan M, Chen Y, He P, Chen F, Peng M, Zhu J. Conductive property of secondary minerals triggered Cr(VI) bioreduction by dissimilatory iron reducing bacteria. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 286:117227. [PMID: 33992904 DOI: 10.1016/j.envpol.2021.117227] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 04/10/2021] [Accepted: 04/21/2021] [Indexed: 06/12/2023]
Abstract
Although secondary minerals have great potential for heavy metal removal, their impact on chromium biogeochemistry in subsurface environments associated with dissimilatory iron reducing bacteria (DIRB) remains poorly characterized. Here, we have investigated the mechanisms of biogenic secondary minerals on the rate of Cr(VI) bioreduction with shewanella oneidensis MR-1. Batch results showed that the biogenic secondary minerals, schwertmannite and jarosite, appreciably increased the Cr(VI) bioreduction rate. UV-vis diffuse reflection spectra showed that schwertmannite and jarosite are semiconductive minerals, which can be activated by MR-1, followed by transferred conduction electrons toward Cr(VI). Cyclic voltammetry and Tafel analysis suggested that the resistance of secondary minerals is a dominant factor controlling Cr(VI) bioreduction. In addition, Cr(VI) adsorption on secondary minerals through ligand exchange promoted Cr(VI) bioreduction by decreasing the electron transfer distance between MR-1 and chromate. Fe(III)/Fe(II) cycling in schwertmannite and jarosite also contributed to Cr(VI) bioreduction as reflected by X-ray photoelectron spectroscopy and Fourier transform infrared spectrometer. Complementary characterizations further verified the contributions of Fe(III)/Fe(II) cycling, Cr(VI) adsorption, and conduction band electron transfer to enhanced Cr(VI) bioreduction. This study provides new insights on the understanding of Cr(VI) bioreduction by semiconductor minerals containing sulfate in subsurface environments.
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Affiliation(s)
- Ke Zhang
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China
| | - Na Li
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China
| | - Peng Liao
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 99 Lingcheng West Road, Guiyang, 550081, China
| | - Yuwen Jin
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China
| | - Qiongyao Li
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China
| | - Min Gan
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China
| | - Yaozong Chen
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China
| | - Peng He
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China
| | - Fang Chen
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China
| | - Mingxian Peng
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China
| | - Jianyu Zhu
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China.
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10
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Huang Y, Zeng Q, Hu L, Zhong H, He Z. Bioreduction performances and mechanisms of Cr(VI) by Sporosarcina saromensis W5, a novel Cr(VI)-reducing facultative anaerobic bacteria. JOURNAL OF HAZARDOUS MATERIALS 2021; 413:125411. [PMID: 33609863 DOI: 10.1016/j.jhazmat.2021.125411] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 02/02/2021] [Accepted: 02/10/2021] [Indexed: 06/12/2023]
Abstract
This study reported a novel facultative anaerobic Cr(VI)-reducing bacteria (Sporosarcina saromensis W5) and investigated its Cr(VI) removal performances and removal mechanisms. The strain W5 was able to grow and reduce Cr(VI) under aerobic and anaerobic environment, and exhibited considerable Cr(VI) reduction capabilities under a wide range of pH (8.0-13.0), temperature (20-40 °C) and initial Cr(VI) concentration (50-800 mg/L). The addition of Cd2+ severely inhibited its growth and Cr(VI) removal, while Cu2+ and Fe3+ significantly enhanced the removal efficiencies. The strain W5 could utilize various electron donors and mediators to accelerate Cr(VI) reduction. Aerobic Cr(VI) reduction mainly occurred in cytoplasm and the final products were soluble organo-Cr(III) complexes. Anaerobic Cr(VI) reduction was located in both cytoplasm and membrane, and the reduction products were soluble organo-Cr(III) complexes and Cr(III) precipitates. The functional groups of hydroxyl, carboxyl and phosphoryl on cell surface participated in the combination with Cr(III). Due to its facultative anaerobic property, S. saromensis W5 offers itself as a promising engineering strain for the bioremediation of Cr(VI)-contaminated areas, especially in hypoxia environments.
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Affiliation(s)
- Yongji Huang
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha 410083, China
| | - Qiang Zeng
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha 410083, China
| | - Liang Hu
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha 410083, China
| | - Hui Zhong
- School of Life Science, Central South University, Changsha 410012, China.
| | - Zhiguo He
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha 410083, China.
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11
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Huang Y, Zeng Q, Hu L, Xiong D, Zhong H, He Z. Column study of enhanced Cr(Ⅵ) removal and removal mechanisms by Sporosarcina saromensis W5 assisted bio-permeable reactive barrier. JOURNAL OF HAZARDOUS MATERIALS 2021; 405:124115. [PMID: 33535357 DOI: 10.1016/j.jhazmat.2020.124115] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 09/24/2020] [Accepted: 09/25/2020] [Indexed: 06/12/2023]
Abstract
In this study, the performances of Sporosarcina saromensis W5 assisted bio-permeable reactive barrier, containing activated carbon (AC) or zero-valent iron (ZVI), were investigated by column experiments in removal of Cr(Ⅵ) from simulated groundwater. The enhanced Cr(Ⅵ) removal performances were observed in biotic columns. Cr(Ⅵ) was first detected in effluent on day 24 and day 85 in Bio-AC and Bio-ZVI columns, respectively whereas it breakthrough only on day 4 and day 15 in AC and ZVI columns. Additionally, Cr(Ⅵ) removal performances induced by biofilm in Bio-QZ columns were promoted with the increase of influent Cr(Ⅵ) concentrations. According to fluorescent images, activated carbon was found to be the best biofilm carrier. Fe0 may not be suitable for microbial colonization because biofilm depolymerization occurred on Fe0 surface. Moreover, high concentration of Cr(Ⅵ) would lag the evolution of biofilm. Magnetite generating was found on the Fe0 surface. X-ray photoelectron spectroscopy (XPS) analysis indicated that the removal mechanism of Cr(Ⅵ) in biotic columns was biotransformation of Cr(Ⅵ) to Cr(Ш) species. Our results may provide a new insight in Cr(Ⅵ) in-situ remediation from groundwater by Bio-PRB system.
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Affiliation(s)
- Yongji Huang
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha 410083, China
| | - Qiang Zeng
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha 410083, China
| | - Liang Hu
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha 410083, China
| | - Daoling Xiong
- Faculty of Materials Metallurgy & Chemistry, Jiangxi University of Science & Technology, Ganzhou, Jiangxi 341000, China
| | - Hui Zhong
- School of Life Science, Central South University, Changsha 410012, China.
| | - Zhiguo He
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha 410083, China; Faculty of Materials Metallurgy & Chemistry, Jiangxi University of Science & Technology, Ganzhou, Jiangxi 341000, China.
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12
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He Y, Guo J, Song Y, Chen Z, Lu C, Han Y, Li H, Hou Y, Zhao R. Acceleration mechanism of bioavailable Fe(Ⅲ) on Te(IV) bioreduction of Shewanella oneidensis MR-1: Promotion of electron generation, electron transfer and energy level. JOURNAL OF HAZARDOUS MATERIALS 2021; 403:123728. [PMID: 32853890 DOI: 10.1016/j.jhazmat.2020.123728] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/09/2020] [Accepted: 08/13/2020] [Indexed: 06/11/2023]
Abstract
The release of highly toxic tellurite into the aquatic environment poses significant environmental risks. The acceleration mechanism and tellurium nanorods (TeNPs) characteristics with bioavailable ferric citrate (Fe(III)) were investigated in the tellurite (Te(IV)) bioreduction. Experiments showed that 5 mM Fe(III) increased the Te(IV) bioreduction rate from 0 to 12.40 mg/(L·h). Cyclic voltammetry, electrochemical impedance spectroscopy and Tafel were used to investigate electron transfer during Te(IV) bioreduction. NADH production (electron production) was significantly enhanced to 138% by Fe(III). Meanwhile Fe(III) stimulated the increase of cytochrome c, resulting in increased electron transport system activity. In addition, Fe(III) facilitated the secretion of extracellular polymeric substances (EPS) and reduced cell membrane permeability, thus reducing the toxicity of Te(IV) to cells. The increase of ATP provided energy for the metabolic process of Te(IV) bioreduction, playing an active role in cell activity. Based on the above analysis, the acceleration mechanism of Fe(III) on Te(IV) bioreduction was proposed from the aspects of electron generation, electron transfer and energy level. Zeta potential and FT-IR spectra indicated that the stability of TeNPs contributed to the covered EPS. This study provides further understanding the acceleration mechanism of Te(IV) bioreduction and promising strategy for improving the stability of TeNPs.
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Affiliation(s)
- Yue He
- School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Jinjing Road 26, Tianjin 300384, China
| | - Jianbo Guo
- School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Jinjing Road 26, Tianjin 300384, China.
| | - Yuanyuan Song
- School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Jinjing Road 26, Tianjin 300384, China
| | - Zhi Chen
- Department of Building, Civil, and Environmental Engineering, Concordia University, 1455 de Maisonneuve Blvd. W. Montreal, Quebec, Canada
| | - Caicai Lu
- School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Jinjing Road 26, Tianjin 300384, China
| | - Yi Han
- School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Jinjing Road 26, Tianjin 300384, China
| | - Haibo Li
- School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Jinjing Road 26, Tianjin 300384, China
| | - Yanan Hou
- School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Jinjing Road 26, Tianjin 300384, China
| | - Rui Zhao
- School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Jinjing Road 26, Tianjin 300384, China
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13
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Rahman Z, Thomas L. Chemical-Assisted Microbially Mediated Chromium (Cr) (VI) Reduction Under the Influence of Various Electron Donors, Redox Mediators, and Other Additives: An Outlook on Enhanced Cr(VI) Removal. Front Microbiol 2021; 11:619766. [PMID: 33584585 PMCID: PMC7875889 DOI: 10.3389/fmicb.2020.619766] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 12/16/2020] [Indexed: 12/13/2022] Open
Abstract
Chromium (Cr) (VI) is a well-known toxin to all types of biological organisms. Over the past few decades, many investigators have employed numerous bioprocesses to neutralize the toxic effects of Cr(VI). One of the main process for its treatment is bioreduction into Cr(III). Key to this process is the ability of microbial enzymes, which facilitate the transfer of electrons into the high valence state of the metal that acts as an electron acceptor. Many underlying previous efforts have stressed on the use of different external organic and inorganic substances as electron donors to promote Cr(VI) reduction process by different microorganisms. The use of various redox mediators enabled electron transport facility for extracellular Cr(VI) reduction and accelerated the reaction. Also, many chemicals have employed diverse roles to improve the Cr(VI) reduction process in different microorganisms. The application of aforementioned materials at the contaminated systems has offered a variety of influence on Cr(VI) bioremediation by altering microbial community structures and functions and redox environment. The collective insights suggest that the knowledge of appropriate implementation of suitable nutrients can strongly inspire the Cr(VI) reduction rate and efficiency. However, a comprehensive information on such substances and their roles and biochemical pathways in different microorganisms remains elusive. In this regard, our review sheds light on the contributions of various chemicals as electron donors, redox mediators, cofactors, etc., on microbial Cr(VI) reduction for enhanced treatment practices.
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Affiliation(s)
- Zeeshanur Rahman
- Department of Botany, Zakir Husain Delhi College, University of Delhi, Delhi, India
| | - Lebin Thomas
- Department of Botany, Hansraj College, University of Delhi, Delhi, India
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14
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Elmeihy R, Shi XC, Tremblay PL, Zhang T. Fast removal of toxic hexavalent chromium from an aqueous solution by high-density Geobacter sulfurreducens. CHEMOSPHERE 2021; 263:128281. [PMID: 33297225 DOI: 10.1016/j.chemosphere.2020.128281] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 07/12/2020] [Accepted: 09/06/2020] [Indexed: 06/12/2023]
Abstract
Hexavalent chromium (Cr(VI)) is a carcinogenic compound that can be removed from contaminated sites by the activity of metal-reducing bacteria. The model bacterium Geobacter sulfurreducens reduces Cr(VI) to less toxic Cr(III) and accumulates Cr ions intracellularly. However, this process is usually slow with small concentrations of Cr(VI) removed in a matter of days. Here, high-density G. sulfurreducens cultures were tested for the capacity to remove Cr(VI) readily. With an initial G. sulfurreducens density of 5.8 × 108 cells ml-1, 99.0 ± 0.8% of 100 mg l-1 Cr(VI) was removed after 20 min. With a higher starting Cr(VI) concentration of 200 mg l-1, G. sulfurreducens with a density of 11.4 × 108 cells ml-1 removed 99.0 ± 0.4% Cr(VI) after 2 h. Experiments performed with cell-free spent medium indicate that extracellular proteins are major contributors for the reduction of Cr(VI) to Cr(III). Furthermore, results show that most Cr(III) ions ultimately end up inside the bacterial cells where they are less susceptible to re-oxidation. The fast Cr(VI) removal rates observed with high-density G. sulfurreducens demonstrate the potential of this bacterium for bioremediation applications such as the cleaning of industrial wastewaters.
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Affiliation(s)
- Rasha Elmeihy
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, 430070, PR China; Agricultural Microbiology Department, Faculty of Agriculture, Benha University, Moshtohor, Kaluybia, 13736, Egypt
| | - Xiao-Chen Shi
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, 430070, PR China; School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan, 430070, PR China; School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070, PR China
| | - Pier-Luc Tremblay
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, 430070, PR China; School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan, 430070, PR China.
| | - Tian Zhang
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, 430070, PR China; School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan, 430070, PR China; School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070, PR China.
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15
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Yang ZN, Hou YN, Zhang B, Cheng HY, Yong YC, Liu WZ, Han JL, Liu SJ, Wang AJ. Insights into palladium nanoparticles produced by Shewanella oneidensis MR-1: Roles of NADH dehydrogenases and hydrogenases. ENVIRONMENTAL RESEARCH 2020; 191:110196. [PMID: 32919957 DOI: 10.1016/j.envres.2020.110196] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 08/22/2020] [Accepted: 09/06/2020] [Indexed: 06/11/2023]
Abstract
Biologically synthesized palladium nanoparticles (bio-Pd) have attracted considerable interest as promising green catalysts for environmental remediation. However, the mechanisms by which microorganisms produce bio-Pd remain unclear. In the present study, we investigated the roles of Shewanella oneidensis MR-1 and its NADH dehydrogenases and hydrogenases (HydA and HyaB) in bio-Pd production using formate as the electron donor. The roles of NADH dehydrogenases and hydrogenases were studied by inhibiting NADH dehydrogenases and using hydrogenase mutants (ΔhydA, ΔhyaB, and ΔhydAΔhyaB), respectively. The results showed ~97% reduction of palladium by S. oneidensis MR-1 after 24 h using 250 μM palladium and 500 μM formate. Electron microscopy images showed the presence of bio-Pd on both the outer and cytoplasmic membranes of S. oneidensis MR-1. However, the inhibition of NADH dehydrogenases in S. oneidensis MR-1 resulted in only ~61% reduction of palladium after 24 h, and bio-Pd were not found on the outer membrane. The mutants lacking one or two hydrogenases removed 91-96% of palladium ions after 24 h and showed more cytoplasmic bio-Pd but less periplasmic bio-Pd. To the best of our knowledge, this is the first study to demonstrate the role of NADH dehydrogenases of S. oneidensis MR-1 in the formation of bio-Pd on the outer membrane. It also demonstrates that the hydrogenases (especially HyaB) of S. oneidensis MR-1 contribute to the formation of bio-Pd in the periplasmic space. This study provides mechanistic insights into the production of biogenic metal nanoparticles towards their possible use in industrial and environmental applications.
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Affiliation(s)
- Zhen-Ni Yang
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ya-Nan Hou
- China Tianjin Key Laboratory of Aquatic Science and Technology, School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin, 300384, China; Tianjin Institute of Industrial Biotechnology, Chinese Academy of Science, Tianjin, 300308, China
| | - Bo Zhang
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Hao-Yi Cheng
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Yang-Chun Yong
- Biofuels Institute, School of the Environment, Jiangsu University, Zhenjiang, 212013, Jiangsu Province, China
| | - Wen-Zong Liu
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Jing-Long Han
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Shuang-Jiang Liu
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China; Environmental Microbiology Research Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Ai-Jie Wang
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China.
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16
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Liu T, Luo X, Wu Y, Reinfelder JR, Yuan X, Li X, Chen D, Li F. Extracellular Electron Shuttling Mediated by Soluble c-Type Cytochromes Produced by Shewanella oneidensis MR-1. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:10577-10587. [PMID: 32692167 DOI: 10.1021/acs.est.9b06868] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
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.
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Affiliation(s)
- Tongxu Liu
- Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, PR China
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangzhou 510650, China
| | - Xiaobo Luo
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, PR China
| | - Yundang Wu
- Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, PR China
| | - John R Reinfelder
- Department of Environmental Sciences, Rutgers University, 14 College Farm Road, New Brunswick, New Jersey 08901, United States
| | - Xiu Yuan
- Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, PR China
| | - Xiaomin Li
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Environmental Theoretical Chemistry, South China Normal University, Guangzhou 510006, China
| | - Dandan Chen
- Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, PR China
| | - Fangbai Li
- Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, PR China
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17
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Luo H, Qi J, Zhou M, Liu G, Lu Y, Zhang R, Zeng C. Enhanced electron transfer on microbial electrosynthesis biocathode by polypyrrole-coated acetogens. BIORESOURCE TECHNOLOGY 2020; 309:123322. [PMID: 32305841 DOI: 10.1016/j.biortech.2020.123322] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/02/2020] [Accepted: 04/03/2020] [Indexed: 06/11/2023]
Abstract
Extracellular electron transfer (EET) is a significant pathway to transport electrons between bacteria and electrode in microbial electrosynthesis systems (MESs). To enhance EET in the MES, a high-conductivity polymer, polypyrrole (PPy), was coated on the surface of mixed culture acetogens in situ and the PPy-coated bacteria were inoculated on the cathode of MES. The charge transfer resistance of PPy-coated biocathode was 33%-70% of that with PPy-uncoated. Acetate production rate and Faradic efficiency in PPy-coated biocathodes increased by 3 to 6 times. After 960 h operation, Acetobacterium, Desulfovibrio, and Acinetobacter dominate the community on the coated and uncoated biocathode. Quinone loop and NADH dehydrogenase to ubiquinone were involved in electron transfer pathway of biocathode and stimulated by PPy coating. Low-level expression of C-type cytochromes on biocathode indicated its less important role in inward EET. The study provided useful information for applications of high-conductivity chemicals in microbial electrosynthesis.
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Affiliation(s)
- Haiping Luo
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Jiaxin Qi
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Meizhou Zhou
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Guangli Liu
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Yaobin Lu
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Renduo Zhang
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Cuiping Zeng
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
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18
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Synthesis of Biogenic Palladium Nanoparticles Using Citrobacter sp. for Application as Anode Electrocatalyst in a Microbial Fuel Cell. Catalysts 2020. [DOI: 10.3390/catal10080838] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Palladium (Pd) is a cheap and effective electrocatalyst that is capable of replacing platinum (Pt) in various applications. However, the problem in using chemically synthesized Pd nanoparticles (PdNPs) is that they are mostly fabricated using toxic chemicals under severe conditions. In this study, we present a more environmentally-friendly process in fabricating biogenic Pd nanoparticles (Bio-PdNPs) using Citrobacter sp. isolated from wastewater sludge. Successful fabrication of Bio-PdNPs was achieved under anaerobic conditions at pH six and a temperature of 30 °C using sodium formate (HCOONa) as an electron donor. Citrobacter sp. showed biosorption capabilities with no enzymatic contribution to Pd(II) uptake during absence of HCOONa in both live and dead cells. Citrobacter sp. live cells also displayed high enzymatic contribution to the removal of Pd(II) by biological reduction. This was confirmed by Scanning Electron Microscope (SEM), Electron Dispersive Spectroscopy (EDS), and X-ray Diffraction (XRD) characterization, which revealed the presence Bio-PdNPs deposited on the bacterial cells. The bio-PdNPs successfully enhanced the anode performance of the Microbial Fuel Cell (MFC). The MFC with the highest Bio-PdNPs loading (4 mg Bio-PdNP/cm2) achieved a maximum power density of 539.3 mW/m3 (4.01 mW/m2) and peak voltage of 328.4 mV.
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19
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Lin WH, Chen SC, Chien CC, Tsang DCW, Lo KH, Kao CM. Application of enhanced bioreduction for hexavalent chromium-polluted groundwater cleanup: Microcosm and microbial diversity studies. ENVIRONMENTAL RESEARCH 2020; 184:109296. [PMID: 32146214 DOI: 10.1016/j.envres.2020.109296] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 01/19/2020] [Accepted: 02/23/2020] [Indexed: 06/10/2023]
Abstract
Hexavalent chromium (Cr6+) is a commonly found heavy metal at polluted groundwater sites. In this study, the effectiveness of Cr6+ bioreduction by the chromium-reducing bacteria was evaluated to remediate Cr6+-contaminated groundwater. Microcosms were constructed using indigenous microbial consortia from a Cr6+-contaminated aquifer as the inocula, and slow-releasing emulsified polycolloid-substrate (ES), cane molasses (CM), and nutrient broth (NB) as the primary substrates. The genes responsible for the bioreduction of Cr6+ and variations in bacterial diversity were evaluated using metagenomics assay. Complete Cr6+ reduction via the biological mechanism was observed within 80 days using CM as the carbon source under anaerobic processes with the increased trivalent chromium (Cr3+) concentrations. Cr6+ removal efficiencies were 83% and 59% in microcosms using ES and NB as the substrates, respectively. Increased bacterial communities associated with Cr6+ bioreduction was observed in microcosms treated with CM and ES. Decreased bacterial communities were observed in NB microcosms. Compared to ES, CM was more applicable by indigenous Cr6+ reduction bacteria and resulted in effective Cr6+ bioreduction, which was possibly due to the growth of Cr6+-reduction related bacteria including Sporolactobacillus, Clostridium, and Ensifer. While NB was applied for specific bacterial selection, it might not be appropriate for electron donor application. These results revealed that substrate addition had significant impact on microbial diversities, which affected Cr6+ bioreduction processes. Results are useful for designing a green and sustainable bioreduction system for Cr6+-polluted groundwater remediation.
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Affiliation(s)
- Wei-Han Lin
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Ssu-Ching Chen
- Department of Life Sciences, National Central University, Chung-Li City, Taoyuan, Taiwan
| | - Chih-Ching Chien
- Graduate School of Biotechnology and Bioengineering, Yuan Ze University, Chung-Li City, Taoyuan, Taiwan
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Kai-Hung Lo
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Chih-Ming Kao
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan.
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20
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Li Y, Chen Z, Shi Y, Luo Q, Wang Y, Wang H, Peng Y, Wang H, He N, Wang Y. Function of c-type cytochromes of Shewanella xiamenensis in enhanced anaerobic bioreduction of Cr(VI) by graphene oxide and graphene oxide/polyvinyl alcohol films. JOURNAL OF HAZARDOUS MATERIALS 2020; 387:122018. [PMID: 31927260 DOI: 10.1016/j.jhazmat.2020.122018] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/29/2019] [Accepted: 01/02/2020] [Indexed: 06/10/2023]
Abstract
Graphene-based materials have been demonstrated to facilitate electron extracellular transfer (EET) of Shewanella. In this study, compared to group lacking graphene oxide (GO)-based materials, GO films-added group and graphene oxide/polyvinyl alcohol (GO/PVA) film-added group delivered 2.67- and 3.13-fold increases in the Cr(VI) reduction by Shewanella xiamenensis, respectively. The whole reduction process could be divided into three stages, including microbial Cr(VI) reduction and GO reduction stage, microbial GO reduction stage and microbial Cr(VI) reduction mediated by reduced graphene oxide (rGO) stage. Moreover, gene analysis revealed that addition of GO and GO/PVA films stimulated overexpression of several c-type cytochrome (c-Cyts) genes, including mtrA, mtrB, mtrC, mtrD, mtrE, mtrF, omcA, petC and SO-4047. Specifically, appreciable Cr(VI) reduction by the strains that overexpressed mtrA, mtrB, mtrC, mtrD, mtrE, mtrF and omcA further confirmed that overexpression of c-Cyts genes indeed enhanced the efficiency of Cr(VI) reduction. Based on these results, the specific function of every c-Cyt was clearly found in Cr(VI) reduction by the induction of GO-based materials. Our finding has disclosed a synergetic mechanism stimulated by GO-based materials to enhance Cr(VI) bioreduction that was not only mediated through the modification of material but also upregulated the expression of functional genes.
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Affiliation(s)
- Yixin Li
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, PR China
| | - Zheng Chen
- School of Environmental Science and Engineering, Tan Kah Kee College, Xiamen University, Zhangzhou, PR China; Zhejiang Provincial Key Laboratory of Watershed Science and Health, School of Public Health and Management, Wenzhou Medical University, Wenzhou, PR China; Fujian Provincial Key Lab of Coastal Basin Environment, Fujian Polytechnic Normal University, Fuqing, PR China.
| | - Yanyan Shi
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, PR China
| | - Qingliu Luo
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, PR China
| | - Yiming Wang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, PR China
| | - Honghui Wang
- School of Environmental Science and Engineering, Tan Kah Kee College, Xiamen University, Zhangzhou, PR China
| | - Yajuan Peng
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, PR China
| | - Haitao Wang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, PR China
| | - Ning He
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, PR China
| | - Yuanpeng Wang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, PR China.
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Chen Z, Liu X, Huang C, Li J, Shen X. Artificial Cytochrome c Mimics: Graphene Oxide-Fe(III) Complex-Coated Molecularly Imprinted Colloidosomes for Selective Photoreduction of Highly Toxic Pollutants. ACS APPLIED MATERIALS & INTERFACES 2020; 12:6615-6626. [PMID: 31904207 DOI: 10.1021/acsami.9b19186] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Our previous works showed that the molecularly imprinted TiO2 photocatalyst has been one of the most efficient materials for selective photooxidation of highly toxic organic pollutants (HTOPs) from complicated wastewater. However, some highly toxic pollutants (e.g., heavy metals) are very stable under the oxidizing environment. Therefore, the design of enzyme-like catalysts to selectively reduce highly toxic pollutants is extremely needed. In this work, inspired by the bioreduction ability of cytochrome c (cyt c, a heme containing metalloprotein), we presented a simple and efficient way to generate an artificial cyt c mimic (ACM) using graphene oxide (GO)-Fe(III) complex-coated molecularly imprinted colloidosomes. Prior to loading of Fe(III) centers to GO for constructing ACMs, GO-coated molecularly imprinted colloidosomes were synthesized via Pickering emulsion polymerization. Similar to a nature cyt c, the ACM contained both the molecular recognition element (molecularly imprinted cavity) and the non-heme electron sink (GO-Fe(III) complex), which resulted in the ACMs having good selectivity toward the enzyme-like reduction of the highly toxic target Cr(VI). Moreover, by using HepG2 cells as model cells, the Cr(VI) solution after treating by ACMs was proved to be safe and nontoxic. To confirm that the present method was universal for constructing ACMs, various GO-Fe(III) complex-coated molecularly imprinted colloidosomes, which could selectively photoreduce other highly toxic inorganic ions and organic pollutants, were also investigated. The ACMs described herein will act as a vector that encourages the design of more functional non-heme enzymes in sensing, environmental separation, clinical diagnose, and delivery of therapeutic agents.
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Affiliation(s)
- Zhiliang Chen
- State Key Laboratory of Environment Health (Incubation), Key Laboratory of Environment and Health, Ministry of Education, Key Laboratory of Environment and Health (Wuhan), Ministry of Environmental Protection, School of Public Health , Tongji Medical College, Huazhong University of Science and Technology , #13 Hangkong Road , Wuhan , Hubei 430030 , China
- Department of Forensic Medicine , Huazhong University of Science and Technology , #13 Hangkong Road , Wuhan , Hubei 430030 , China
| | - Xiaojie Liu
- State Key Laboratory of Environment Health (Incubation), Key Laboratory of Environment and Health, Ministry of Education, Key Laboratory of Environment and Health (Wuhan), Ministry of Environmental Protection, School of Public Health , Tongji Medical College, Huazhong University of Science and Technology , #13 Hangkong Road , Wuhan , Hubei 430030 , China
| | - Chuixiu Huang
- Department of Forensic Medicine , Huazhong University of Science and Technology , #13 Hangkong Road , Wuhan , Hubei 430030 , China
| | - Jilai Li
- Institute of Theoretical Chemistry , Jilin University , Changchun , Jilin 130023 , China
| | - Xiantao Shen
- State Key Laboratory of Environment Health (Incubation), Key Laboratory of Environment and Health, Ministry of Education, Key Laboratory of Environment and Health (Wuhan), Ministry of Environmental Protection, School of Public Health , Tongji Medical College, Huazhong University of Science and Technology , #13 Hangkong Road , Wuhan , Hubei 430030 , China
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22
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Zhu Y, Yan J, Xia L, Zhang X, Luo L. Mechanisms of Cr(VI) reduction by Bacillus sp. CRB-1, a novel Cr(VI)-reducing bacterium isolated from tannery activated sludge. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 186:109792. [PMID: 31629191 DOI: 10.1016/j.ecoenv.2019.109792] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 10/07/2019] [Accepted: 10/10/2019] [Indexed: 06/10/2023]
Abstract
Cr(VI) reduction by microorganisms has been extensively reported, however, the mechanism of Cr(VI) reduction varies among different microorganisms. In this study, a Cr(VI)-reducing bacterium identified as Bacillus sp. was isolated from tannery activated sludge, strain CRB-1 was able to completely reduce 50 mg/L of Cr(VI) within 24 h under aerobic conditions and exhibited considerable Cr(VI) removal efficiency in the pH range from 7.0 to 9.0, temperature 24-42 °C. Cr(VI) reduction assays with resting cells, permeabilized cells, and subcellular fractions suggested that Cr(VI) reduction mainly occurred in the cytoplasm. According to qRT-PCR analysis, a chrA gene and a nitR2 gene were up-regulated under Cr(VI) stress. Heterologous expression of the chrA gene and the nitR2 gene indicated that ChrA was associated with Cr(VI) resistance, while NitR2 was responsible for Cr(VI) reduction. Furthermore, soluble end products were detected. On the basis of FTIR, it was speculated that the formation of soluble end products may be due to the complexation of EPS with Cr(III). Consequently, the Cr(VI)-reducing ability of strain CRB-1 and its chromate reductases enables CRB-1 a potential candidate for Cr(VI) bioremediation.
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Affiliation(s)
- Yunfei Zhu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Junwei Yan
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Li Xia
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Xiang Zhang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Lixin Luo
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China.
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23
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Mengke-Li, Yuting-Zhuo, Yuting-Hu, Shuzhen-Li, Liang-Hu, Hui-Zhong, Zhiguo-He. Exploration on the bioreduction mechanism of Cr(Ⅵ) by a gram-positive bacterium: Pseudochrobactrum saccharolyticum W1. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 184:109636. [PMID: 31536849 DOI: 10.1016/j.ecoenv.2019.109636] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 08/30/2019] [Accepted: 09/03/2019] [Indexed: 06/10/2023]
Abstract
Bioremediation of chromium (Cr(Ⅵ)) contaminations has been widely reported, but the research on its removal mechanism is still scarce. Studies on Cr(Ⅵ) removal by strains affiliated to genus Pseudochobactrum revealed the Cr(Ⅵ) efficiency removal through the reduction of Cr(Ⅵ) to Cr(Ⅲ). However, the location of Cr(Ⅵ) reduction reaction and exact mechanism are still unspecified. In this work, a Gram-positive bacterial strain, Pseudochrobactrum saccharolyticum W1 (P. saccharolyticum W1) was isolated and tested to remove approximately 53.7% of Cr(Ⅵ) (initial concentration was 200 mg L-1) from the MSM medium. Analysis of SEM-EDS and TEM-EDS indicated that chromium-containing particles precipitated both on the cell surface and in the cytoplasm. Batch experiments indicated that the heat-treated bacterial cells almost had no ability to remove Cr(Ⅵ) from solution, while the resting cells could remove 62.0% of Cr(Ⅵ) at the initial concentration of 10 mg L-1. Additionally, at this concentration, 64.8% and 70.8% of Cr(Ⅵ) was reduced by cell envelope components and intracellular soluble substances after 6 h, respectively. These results suggested that the removal of Cr(Ⅵ) by P. saccharolyticum W1 was through direct reduction, which occurred on both cell envelop and cytoplasm. The results also showed that cytoplasm was the main site for Cr(Ⅵ) reduction compared to the cell envelop. Further analysis of FTIR and XPS verified that C-H, C-C, CO, C-OH and C-O-C groups of cells involved in correlation with chromium during Cr(Ⅵ) reduction. The study offered an insight into the Cr(VI) reduction mechanism of P. saccharolyticum W1.
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Gajaraj S, Sun X, Zhang C, Hu Z. Improved chromium reduction and removal from wastewater in continuous flow bioelectrochemical systems. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:31945-31955. [PMID: 31493075 DOI: 10.1007/s11356-019-06289-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 08/26/2019] [Indexed: 06/10/2023]
Abstract
Bioelectrochemical systems (BESs) including microbial electrolysis cells (MECs) and microbial fuel cells (MFCs) are promising for hexavalent chromium [Cr(VI)] reduction and total chromium (Cr) removal from wastewater. This study assessed the performance of simple, inexpensive, and continuous flow BESs with neither cathode catalyst nor proton exchange membrane for Cr(VI) reduction and total Cr removal. The effect of bioreactor configuration and wastewater feed mode on the performance of the BESs was investigated. Biological Cr(VI) reduction in the MEC followed a first-order kinetics with a rate constant of 0.103 d-1, significantly higher than that of the control (0.033 d-1). For comparison, the first-order reduction rate constants in the MFCs with the Cr(VI) fed to the anodic and the cathodic zones were 0.072 and 0.064 d-1, respectively. The BESs improved total Cr removal through coprecipitating Cr(III) and phosphors as evidenced from the scanning electron microscopy energy-dispersive X-ray spectroscopy analysis. The total Cr removal efficiencies in the control, MFCs, and MEC were 26.1%, 56.7%, and 66.2%, respectively. Only 25.1% to 26.7% of total Cr was present intracellularly in the BESs (both MFCs and MEC), whereas 31.8% ± 1.4% and 38.0% ± 0.9% of total Cr in the anodic and cathodic zones of the control were present intracellularly. Overall, the BESs demonstrated a great potential to reduce Cr(VI) and remove total Cr with the MEC having the fastest Cr(VI) reduction and most efficient total Cr removal. Furthermore, the BESs significantly reduced the intracellular total Cr content.
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Affiliation(s)
- Shashikanth Gajaraj
- Department of Civil & Environmental Engineering, University of Missouri, Columbia, MO, 65211, USA
- HDR, Inc., Kansas City, MO, 64131, USA
| | - Xining Sun
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China
| | - Chiqian Zhang
- Department of Civil & Environmental Engineering, University of Missouri, Columbia, MO, 65211, USA.
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
| | - Zhiqiang Hu
- Department of Civil & Environmental Engineering, University of Missouri, Columbia, MO, 65211, USA.
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25
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Shi J, Zhang B, Qiu R, Lai C, Jiang Y, He C, Guo J. Microbial Chromate Reduction Coupled to Anaerobic Oxidation of Elemental Sulfur or Zerovalent Iron. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:3198-3207. [PMID: 30776217 DOI: 10.1021/acs.est.8b05053] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Chromate (Cr(VI)), as one of ubiquitous contaminants in groundwater, has posed a major threat to public health and ecological environment. Although various electron donors (e.g., organic carbon, hydrogen, and methane) have been proposed to drive chromate removal from contaminated water, little is known for microbial chromate reduction coupled to elemental sulfur (S(0)) or zerovalent iron (Fe(0)) oxidation. This study demonstrated chromate could be biologically reduced by using S(0) or Fe(0) as inorganic electron donor. After 60-day cultivation, the sludge achieved a high Cr(VI) removal efficiency of 92.9 ± 1.1% and 98.1 ± 1.2% in two independent systems with S(0) or Fe(0) as the sole electron donor, respectively. The deposited Cr(III) was identified as the main reduction product based on X-ray photoelectron spectroscopy. High-throughput 16S rRNA gene sequencing indicated that Cr(VI) reduction coupled to S(0) or Fe(0) oxidation was mediated synergically by a microbial consortia. In such the consortia, S(0)- or Fe(0)-oxidizing bacteria (e.g., Thiobacillus or Ferrovibrio) could generate volatile fatty acids as metabolites, which were further utilized by chromate-reducing bacteria (e.g., Geobacter or Desulfovibrio) to reduce chromate. Our findings advance our understanding on microbial chromate reduction supported by solid electron donors and also offer a promising process for groundwater remediation.
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Affiliation(s)
- Jiaxin Shi
- School of Water Resources and Environment, MOE Key Laboratory of Groundwater Circulation and Environmental Evolution , China University of Geosciences (Beijing) , Beijing 100083 , P. R. China
| | - Baogang Zhang
- School of Water Resources and Environment, MOE Key Laboratory of Groundwater Circulation and Environmental Evolution , China University of Geosciences (Beijing) , Beijing 100083 , P. R. China
| | - Rui Qiu
- School of Water Resources and Environment, MOE Key Laboratory of Groundwater Circulation and Environmental Evolution , China University of Geosciences (Beijing) , Beijing 100083 , P. R. China
| | - Chunyu Lai
- Advanced Water Management Centre , The University of Queensland , St Lucia , Queensland 4072 , Australia
| | - Yufeng Jiang
- School of Water Resources and Environment, MOE Key Laboratory of Groundwater Circulation and Environmental Evolution , China University of Geosciences (Beijing) , Beijing 100083 , P. R. China
| | - Chao He
- School of Water Resources and Environment, MOE Key Laboratory of Groundwater Circulation and Environmental Evolution , China University of Geosciences (Beijing) , Beijing 100083 , P. R. China
| | - Jianhua Guo
- Advanced Water Management Centre , The University of Queensland , St Lucia , Queensland 4072 , Australia
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26
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LUO X, WU Y, LIU T, LI F, LI X, CHEN D, WANG Y. Quantifying Redox Dynamics of c-Type Cytochromes in a Living Cell Suspension of Dissimilatory Metal-reducing Bacteria. ANAL SCI 2019; 35:315-321. [DOI: 10.2116/analsci.18p394] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Xiaobo LUO
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences
- Guangdong Institute of Eco-environmental Science & Technology, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management
- University of Chinese Academy of Sciences
| | - Yundang WU
- Guangdong Institute of Eco-environmental Science & Technology, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management
| | - Tongxu LIU
- Guangdong Institute of Eco-environmental Science & Technology, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management
| | - Fangbai LI
- Guangdong Institute of Eco-environmental Science & Technology, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management
| | - Xiaomin LI
- The Environmental Research Institute, MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University
| | - Dandan CHEN
- Guangdong Institute of Eco-environmental Science & Technology, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management
| | - Ying WANG
- Guangdong Institute of Eco-environmental Science & Technology, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management
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27
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Liu T, Chen D, Li X, Li F. Microbially mediated coupling of nitrate reduction and Fe(II) oxidation under anoxic conditions. FEMS Microbiol Ecol 2019; 95:5371120. [DOI: 10.1093/femsec/fiz030] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 03/06/2019] [Indexed: 11/12/2022] Open
Affiliation(s)
- Tongxu Liu
- Guangzhou Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-environmental Science & Technology, Guangzhou 510650, P. R. China
| | - Dandan Chen
- Guangzhou Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-environmental Science & Technology, Guangzhou 510650, P. R. China
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Xiaomin Li
- The Environmental Research Institute, MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, P. R. China
| | - Fangbai Li
- Guangzhou Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-environmental Science & Technology, Guangzhou 510650, P. R. China
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28
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Liu W, Wu Y, Liu T, Li F, Dong H, Jing M. Influence of Incubation Temperature on 9,10-Anthraquinone-2-Sulfonate (AQS)-Mediated Extracellular Electron Transfer. Front Microbiol 2019; 10:464. [PMID: 30894849 PMCID: PMC6414795 DOI: 10.3389/fmicb.2019.00464] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 02/21/2019] [Indexed: 11/13/2022] Open
Abstract
The electron shuttling process has been recognized as an important microbial respiration process. Because the incubation temperature can influence both the reactivity of electron mediators and cell growth, it may also affect the electron-shuttle-mediated extracellular electron transfer (EET) process. Here, the effect of incubation temperature (22-38°C) was investigated in a bioelectrochemical system (BES) using Shewanella oneidensis MR-1 and 50 μM of 9,10-anthraquinone-2-sulfonate (AQS). We found that current generation increased as the temperature was increased from 22 to 34°C and then decreased sharply at 38°C. The biofilm biomass, as indicated by the total protein extracted from the electrode, increased as the temperature increased from 22 to 34°C and then decreased at 38°C, mirroring the current generation results. These results were further confirmed by increasing the temperature slowly, step-by-step, in a single BES with a constant biofilm biomass, suggesting that the EET rates could be substantially influenced by temperature, even with the same biofilm. The effects of temperature on the AQS bioreduction rate, c-type cytochrome (c-Cyts)-bound-cofactor-mediated EET, the AQS mid-point potential, and the AQS diffusion coefficient were studied. From these results, we were able to conclude that temperature influenced the EET rates by changing the c-Cyts-bound-cofactor-mediated EET process and the AQS bioreduction rate, and that the change in biofilm formation was a dominant factor influencing the overall EET rates. These findings should contribute to the fundamental understanding of EET processes. Moreover, optimization of the operating parameters for current generation will be helpful for the practical application of bioelectrochemical techniques.
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Affiliation(s)
- Wei Liu
- College of Materials and Energy, South China Agricultural University, Guangzhou, China
| | - Yundang Wu
- Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science and Technology, Guangzhou, China
| | - Tongxu Liu
- Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science and Technology, Guangzhou, China
| | - Fangbai Li
- Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science and Technology, Guangzhou, China
| | - Hui Dong
- College of Materials and Energy, South China Agricultural University, Guangzhou, China
| | - Meiqing Jing
- Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science and Technology, Guangzhou, China
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29
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Chen G, Han J, Mu Y, Yu H, Qin L. Two-stage chromium isotope fractionation during microbial Cr(VI) reduction. WATER RESEARCH 2019; 148:10-18. [PMID: 30343194 DOI: 10.1016/j.watres.2018.09.034] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 09/17/2018] [Accepted: 09/18/2018] [Indexed: 06/08/2023]
Abstract
Chromium isotope fractionation analysis is a promising approach for the assessment of microbial Cr(VI) reduction in groundwater. Understanding the mechanisms and other parameters that control Cr isotope fractionation factors (between the product Cr(III) and reactant Cr (VI)) in microbial Cr(VI) reduction is critical to this application. To date, such studies are very limited. Here, the influence of critical factors on observed Cr isotope fractionation during Cr(VI) reduction by Shewanella oneidensis MR-1 under various conditions was investigated. The Cr(VI) concentration and Cr isotope ratio measurements were conducted on unreacted Cr(VI) remaining in solution to determine Cr isotope fractionation factors. The changes in ambient environmental conditions (e.g., pH, temperature) have limited influence on Cr isotope fractionation factors. However, as a result of Cr(VI) consumption as the experiments proceed, the change in bioavailability of Cr(VI) has a significant impact on Cr isotope fractionation factors. For example, in temperature-controlled experiments, Cr isotope fractionation showed two-stage behavior: during Stage I, the values of ε were -2.81 ± 0.19‰ and -2.60 ± 0.14‰ at 18 °C and 34 °C, respectively; during Stage II, as Cr(VI) reduction progressed, Cr isotope fractionation was significantly masked, and the ε values decreased to -0.98 ± 0.49‰ and -1.01 ± 0.11‰ at 18 °C and 34 °C, respectively. Similar two-stage isotope fractionation behaviors were observed in pH-controlled experiments (pH = 6.0 and 7.2) and in experiments with and without the addition of a competing electron acceptor (nitrate). Masking of isotope fractionation in Stage II indicated restrictions on the bioavailability of Cr(VI) and mass-transfer limitations. This study provides an explanation for the variation in Cr isotope fractionation factors during microbial Cr(VI) reduction in the environment, furthering the viability of Cr isotope ratio analysis as an approach in understanding Cr biogeochemical cycling.
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Affiliation(s)
- Guojun Chen
- CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, 230026, China
| | - Juncheng Han
- CAS Key Laboratory for Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei, 230026, China
| | - Yang Mu
- CAS Key Laboratory for Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei, 230026, China
| | - Huimin Yu
- CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, 230026, China
| | - Liping Qin
- CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, 230026, China; State Key Laboratory of Geological Processes and Mineral Resources, University of Geosciences, Beijing, China.
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30
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Pereira EJ, Damare S, Furtado B, Ramaiah N. Response to chromate challenge by marine Staphylococcus sp. NIOMR8 evaluated by differential protein expression. 3 Biotech 2018; 8:500. [PMID: 30498673 DOI: 10.1007/s13205-018-1522-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 11/17/2018] [Indexed: 11/28/2022] Open
Abstract
Liquid Chromatography-Mass Spectrometry-Quadrupole Time of Flight (LC/MS QToF) protein profiling of marine-derived Staphyloccous gallinarum NIOMR8 was carried out to evaluate proteins conferring chromate (Cr6+) resistance and possible metabolic pathways that were altered as a result. Expressional (up or down-regulation) responses to varying Cr6+ (0, 50, 100, 150, and 200 µg mL- 1) concentrations varied, with as many as 346 proteins identified. Most number of proteins-their numbers in parentheses-were up-regulated when grown in medium with 50 µg mL- 1 (162) and, down-regulated in medium with 100 (281) or 200 µg mL- 1 Cr6+ (280). Among these, eight proteins were commonly up-regulated, while 58 were commonly down-regulated across all conditions of Cr6+. Expression of protein moieties in metabolic pathways like translation (38), transcription (14), replication (18) and repair (4), metabolism of carbohydrates (26), amino acids (27), nucleotides (17), and membrane transport (21) was evidenced. Up-regulation patterns suggest that reduction of molecular oxygen (5), DNA repair (4) and peptide misfolding (7) were the potential protective mechanisms employed to counter Cr6+ stress. Additionally, proteins associated with biofilm and cell wall biogenesis highlight their hypothetical involvement in toxicity tolerance. Results also indicate that at higher concentrations of Cr6+, down-regulation of functional proteins impedes normal cellular functions.
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Affiliation(s)
- Elroy Joe Pereira
- 1Biological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004 India
| | - Samir Damare
- 1Biological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004 India
| | - Bliss Furtado
- 1Biological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004 India
- Present Address: Department of Microbiology, Copernicus University, Toruń, Poland
| | - Nagappa Ramaiah
- 1Biological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004 India
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31
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Gong Y, Werth CJ, He Y, Su Y, Zhang Y, Zhou X. Intracellular versus extracellular accumulation of Hexavalent chromium reduction products by Geobacter sulfurreducens PCA. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 240:485-492. [PMID: 29754098 DOI: 10.1016/j.envpol.2018.04.046] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 04/06/2018] [Accepted: 04/09/2018] [Indexed: 06/08/2023]
Abstract
Hexavalent chromium (Cr(VI)) reduction by Geobacter sulfurreducens PCA was evaluated in batch experiments, and the form and amounts of intracellular and extra-cellular Cr(VI) reduction products were determined over time. The first-order Cr(VI) reduction rate per unit mass of cells was consistent for different initial cell concentrations, and approximately equal to (2.065 ± 0.389) x 10-9 mL CFU-1 h-1. A portion of the reduced Cr(VI) products precipitated on Geobacter cell walls as Cr(III) and was bound via carboxylate functional groups, a portion accumulated inside Geobacter cells, and another portion existed as soluble Cr(III) or organo-Cr(III) released to solution. A mass balance analysis of total chromium in aqueous media, on cell walls, and inside cells was determined as a function of time, and with different initial cell concentrations. Mass balances were between 92% and 98%, and indicated Cr(VI) reduction products accumulate more on cell walls and inside cells with time and with increasing initial cell concentration, as opposed to particulates in aqueous solution. Reduced Cr(VI) products both in solution and on cell surfaces appear to form organo-Cr(III) complexes, and our results suggest that such complexes are more stable to reoxidation than aqueous Cr(III) or Cr(OH)3. Chromium inside cells is also likely more stable to reoxidation, both because it can form organic complexes, and it is separated by the cell membrane from solution conditions. Hence, Cr(VI) reduction products in groundwater during bioremediation may become more stable against re-oxidation, and may pose a lower risk to human health, over time and with greater initial biomass densities.
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Affiliation(s)
- Yufeng Gong
- College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai, 200092, China
| | - Charles J Werth
- Civil, Architectural and Environmental Engineering, University of Texas at Austin, 301 East Dean Keeton St., Stop C1786, Austin, TX, 78712, USA
| | - Yaxue He
- College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai, 200092, China
| | - Yiming Su
- Department of Civil and Environmental Engineering, University of California, Los Angeles, CA, 90095, USA
| | - Yalei Zhang
- College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai, 200092, China
| | - Xuefei Zhou
- College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai, 200092, China.
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Bai YN, Lu YZ, Shen N, Lau TC, Zeng RJ. Investigation of Cr(VI) reduction potential and mechanism by Caldicellulosiruptor saccharolyticus under glucose fermentation condition. JOURNAL OF HAZARDOUS MATERIALS 2018; 344:585-592. [PMID: 29102641 DOI: 10.1016/j.jhazmat.2017.10.059] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 10/25/2017] [Accepted: 10/28/2017] [Indexed: 06/07/2023]
Abstract
This study examined the microbial reduction of hexavalent chromium [Cr(VI)] by an extremely thermophilic bacterium, Caldicellulosiruptor saccharolyticus, under glucose fermentation conditions at 70°C. Experimentation with different initial Cr(VI) concentrations confirmed that C. saccharolyticus had the ability to reduce Cr(VI) and immobilize Cr(III). At a concentration of 40mg/L, Cr(VI) was completely reduced within 12h, and 97% of the reduction product Cr(III) precipitated on the cell surface. Cr(VI) reduction was accelerated by the addition of neutral red (NR, an electron mediator), resulting in the reduction time shortened to 1h. The addition of CuCl2, a Ni-Fe hydrogenase inhibitor, also enhanced Cr(VI) reduction. Additionally, analysis of the relationship between Cr(VI) reduction and glucose fermentation suggested that different electron sources acted during CuCl2 and NR conditions. Hydrogen served as an electron donor under normal fermentation and NR conditions with the catalysis of Ni-Fe hydrogenase. However, when the activity of Ni-Fe hydrogenase was inhibited by CuCl2, C. saccharolyticus directly used reduction equivalents during glucose fermentation for intracellular Cr(VI) reduction. Therefore, our findings demonstrated high Cr(VI) reduction ability and different electron transfer pathways during Cr(VI) reduction by C. saccharolyticus.
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Affiliation(s)
- Ya-Nan Bai
- Advanced Laboratory for Environmental Research and Technology, USTC-CityU, Suzhou, PR China; School of Life Sciences, University of Science and Technology of China, Hefei 230026, PR China
| | - Yong-Ze Lu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, PR China
| | - Nan Shen
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, PR China
| | - Tai-Chu Lau
- Advanced Laboratory for Environmental Research and Technology, USTC-CityU, Suzhou, PR China; State Key Laboratory in Marine Pollution, Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong
| | - Raymond Jianxiong Zeng
- Advanced Laboratory for Environmental Research and Technology, USTC-CityU, Suzhou, PR China; School of Life Sciences, University of Science and Technology of China, Hefei 230026, PR China; CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, PR China.
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Baaziz H, Gambari C, Boyeldieu A, Ali Chaouche A, Alatou R, Méjean V, Jourlin-Castelli C, Fons M. ChrASO, the chromate efflux pump of Shewanella oneidensis, improves chromate survival and reduction. PLoS One 2017; 12:e0188516. [PMID: 29166414 PMCID: PMC5699817 DOI: 10.1371/journal.pone.0188516] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 11/08/2017] [Indexed: 01/22/2023] Open
Abstract
The chromate efflux pump encoding gene chrASO was identified on the chromosome of Shewanella oneidensis MR1. Although chrASO is expressed without chromate, its expression level increases when Cr(VI) is added. When deleted, the resulting mutant ΔchrASO exhibits a chromate sensitive phenotype compared to that of the wild-type strain. Interestingly, heterologous expression of chrASO in E. coli confers resistance to high chromate concentration. Moreover, expression of chrASO in S. oneidensis and E. coli significantly improves Cr(VI) reduction. This effect could result either from extracytoplasmic chromate reduction or from a better cell survival leading to enhanced Cr(VI) reduction.
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Affiliation(s)
- Hiba Baaziz
- Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université, Centre National de la Recherche Scientifique, Marseille, France
- Laboratoire de Biologie Moléculaire et Cellulaire, Université des Frères Mentouri Constantine 1, Constantine, Algeria
| | - Cyril Gambari
- Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université, Centre National de la Recherche Scientifique, Marseille, France
| | - Anne Boyeldieu
- Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université, Centre National de la Recherche Scientifique, Marseille, France
| | - Amine Ali Chaouche
- Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université, Centre National de la Recherche Scientifique, Marseille, France
| | - Radia Alatou
- Laboratoire de Biologie Moléculaire et Cellulaire, Université des Frères Mentouri Constantine 1, Constantine, Algeria
| | - Vincent Méjean
- Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université, Centre National de la Recherche Scientifique, Marseille, France
| | - Cécile Jourlin-Castelli
- Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université, Centre National de la Recherche Scientifique, Marseille, France
| | - Michel Fons
- Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université, Centre National de la Recherche Scientifique, Marseille, France
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Copper (II) binding of NAD(P)H- flavin oxidoreductase (NfoR) enhances its Cr (VI)-reducing ability. Sci Rep 2017; 7:15481. [PMID: 29133854 PMCID: PMC5684319 DOI: 10.1038/s41598-017-15588-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 10/23/2017] [Indexed: 12/16/2022] Open
Abstract
Microbes can reduce hexavalent chromium Cr (VI) to the less toxic and soluble trivalent Cr (III). Copper stimulates microbial reduction of Cr (VI) by the Bacillus, Ochrobactrum, and Gluconobacter species; however, the mechanism remains unclear. In our study, the rate of Cr (VI) reduction by Staphylococcus aureus LZ-01 was increased by 210 % when supplemented with 60 μM Cu (II). A putative NAD(P)H-flavin oxidoreductase gene (nfoR) was upregulated under Cr (VI) stress. NfoR-knockout mutant displayed impaired reduction of Cr (VI) and Cu (II)-enhanced Cr (VI) reduction by nfoR isogenic mutant was attenuated in the presence of Cu (II). In vitro tests showed an increased Vmax value of 25.22 μM min−1 mg−1 NfoR in the presence of Cu (II). Together, these results indicate that NfoR is responsible for Cu (II) enhancement. Isothermal titration calorimetry (ITC) assays confirmed the interaction of NfoR with Cu (II) at the dissociation constant of 85.5 μM. Site-directed mutagenesis indicates that His100, His128, and Met165 residues may be important for Cu (II) binding, while Cys163 is necessary for the FMN binding of NfoR. These findings show that Cu (II)-enhanced NfoR belongs to a new branch of Cr (VI) reductases and profoundly influences Cr (VI) reduction.
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