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Chen RP, Wei XY, Gan CH, Cai BC, Xu WJ, Niyazi S, Wang Q, Yu L, Min HH, Yong Q. The acceleration on decolorization of azo dyes by magnetic lignin-based materials via enhancing the extracellular electron transfer. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 341:118022. [PMID: 37150166 DOI: 10.1016/j.jenvman.2023.118022] [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: 04/19/2023] [Accepted: 04/24/2023] [Indexed: 05/09/2023]
Abstract
Two novel and eco-friendly redox mediators (RMs), magnetic oxidative vanillin (MOV) and magnetic oxidative syringaldehyde (MOS), both derived from lignin, were prepared to improve the decolorization of the methyl orange (MO) dye. The Decolorization Efficiency (DE) of MO in the batch experiments with MOV and MOS were increased by more than 60% and 22%, respectively, when compared to the control experiment without magnetic RMs. Moreover, the two magnetic RMs could maintain stable DE of MO in sequenced batch reactors (SBRs), and negligible leaching of the oxidized lignin monomers was observed under various environmental conditions. Density Function Theory (DFT) calculations were used to propose three potential biodegradation mechanisms for azo dyes, and the key intermediates were confirmed using high-performance liquid chromatography. This study proposed a feasible strategy for functional utilization of lignin resource, as well as a practical method for effectively treating azo dye-containing wastewater.
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Affiliation(s)
- Rong-Ping Chen
- Department of Environmental Engineering, College of Biology and Environment, Nanjing Forestry University, Nanjing, 210037, China; College of Biology and the Environment, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, China
| | - Xin-Yuan Wei
- Department of Environmental Engineering, College of Biology and Environment, Nanjing Forestry University, Nanjing, 210037, China
| | - Cheng-Hao Gan
- Department of Environmental Engineering, College of Biology and Environment, Nanjing Forestry University, Nanjing, 210037, China
| | - Bing-Cai Cai
- Department of Environmental Engineering, College of Biology and Environment, Nanjing Forestry University, Nanjing, 210037, China
| | - Wen-Jie Xu
- Department of Environmental Engineering, College of Biology and Environment, Nanjing Forestry University, Nanjing, 210037, China
| | - Shareen Niyazi
- Department of Environmental Engineering, College of Biology and Environment, Nanjing Forestry University, Nanjing, 210037, China
| | - Quan Wang
- Department of Environmental Engineering, College of Biology and Environment, Nanjing Forestry University, Nanjing, 210037, China
| | - Lei Yu
- Department of Environmental Engineering, College of Biology and Environment, Nanjing Forestry University, Nanjing, 210037, China; College of Biology and the Environment, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, China.
| | - Hui-Hua Min
- Advanced Analysis and Testing Center, Nanjing Forestry University, Nanjing, 210037, China
| | - Qiang Yong
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, China.
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Wang ZY, Ju CJ, Zhang R, Hua JQ, Chen RP, Liu GX, Yin K, Yu L. Acceleration of the bio-reduction of methyl orange by a magnetic and extracellular polymeric substance nanocomposite. JOURNAL OF HAZARDOUS MATERIALS 2021; 420:126576. [PMID: 34252658 DOI: 10.1016/j.jhazmat.2021.126576] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 06/13/2023]
Abstract
Extracellular electron transfer (EET) plays an important role in bio-reduction of environmental pollutants. Extracellular polymeric substances (EPS), a kind of biogenic macromolecule, contain functional groups responsible for acceleration of EET. In this study, azo dye-methyl orange (MO) was chosen as a model pollutant, and a Fe3O4 and EPS nanocomposite (Fe3O4@EPS) was prepared to evaluate its promotion on the bio-reduction of MO. The flower-like core-shell configuration of Fe3O4@EPS with a 12 nm of light layer of EPS was confirmed by TEM. The redox ability of EPS was well reserved on Fe3O4@EPS by FTIR and electrochemical test. The application of Fe3O4@EPS on sustained acceleration of MO decolorization were confirmed by batch experiments and anaerobic sequenced batch reactors. Due to biocompatibility of the biogenic shell, the as-prepared Fe3O4@EPS exhibited low toxic to microorganisms by the Live/dead cell test. Moreover, negligible leaching of EPS under high concentration of various anions and less than 10% of EPS was released under extreme acidic and basic pH condition. The results of study provided a new preparation method of biological intimate and environmentally friendly redox mediators and suggested a feasible way for its use on bio-reduction of pollutants.
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Affiliation(s)
- Zi-Yang Wang
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China; School of Environmental Science, Nanjing XiaoZhuang University, Nanjing 211171, China
| | - Cheng-Jia Ju
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Rui Zhang
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Jing-Qiu Hua
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Rong-Ping Chen
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Guang-Xiang Liu
- School of Environmental Science, Nanjing XiaoZhuang University, Nanjing 211171, China
| | - Ke Yin
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Lei Yu
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China; School of Environmental Science, Nanjing XiaoZhuang University, Nanjing 211171, China.
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3
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Zhang Q, Xie X, Liu Y, Zheng X, Wang Y, Cong J, Yu C, Liu N, He Z, Liu J, Sand W. Sugar sources as Co-substrates promoting the degradation of refractory dye: A comparative study. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 184:109613. [PMID: 31491606 DOI: 10.1016/j.ecoenv.2019.109613] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 08/23/2019] [Accepted: 08/26/2019] [Indexed: 06/10/2023]
Abstract
Four sugar sources were used as co-substrates to promote the degradation of a selected refractory dye reactive black 5 (RB5) by the natural bacterial flora DDMZ1. The boosting performance of the four sugar sources on RB5 decolorization ranked as: fructose > sucrose > glucose > glucose + fructose. Kinetic results of these four co-metabolism systems agreed well with a first-order kinetic model. Four sugar sources stimulated the extracellular azoreductase secretion causing enhanced enzyme activity. An increased formation of low molecular weight intermediates was caused by the addition of sugar sources. The toxicity of RB5 degradation products was significantly reduced in the presence of sugar sources. The bacterial community structure differed remarkably as a result of sugar sources addition. For a fructose addition, a considerably enriched population of the functional species Burkholderia-Paraburkholderia and Klebsiella was noted. The results enlarge our knowledge of the microkinetic and microbiological mechanisms of co-metabolic degradation of refractory pollutants.
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Affiliation(s)
- Qingyun Zhang
- Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China
| | - Xuehui Xie
- Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China.
| | - Yanbiao Liu
- Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China
| | - Xiulin Zheng
- Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, PR China
| | - Yiqin Wang
- Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, PR China
| | - Junhao Cong
- Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, PR China
| | - Chengzhi Yu
- Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, PR China
| | - Na Liu
- School of Environment and Surveying Engineering, Suzhou University, Suzhou, Anhui, 234000, China
| | - Zhenjiang He
- School of Metallurgy and Environment, Central South University, Changsha, 410083, PR China
| | - Jianshe Liu
- Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China
| | - Wolfgang Sand
- Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, PR China; Institute of Biosciences, Freiberg University of Mining and Technology, Freiberg, 09599, Germany
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Zhang Q, Xie X, Liu Y, Zheng X, Wang Y, Cong J, Yu C, Liu N, Liu J, Sand W. Fructose as an additional co-metabolite promotes refractory dye degradation: Performance and mechanism. BIORESOURCE TECHNOLOGY 2019; 280:430-440. [PMID: 30784993 DOI: 10.1016/j.biortech.2019.02.046] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 02/07/2019] [Accepted: 02/08/2019] [Indexed: 06/09/2023]
Abstract
In this work, the performance and mechanism for the boosting effects of fructose as an additional co-metabolite towards the biological treatment of reactive black 5 were systematically investigated. A decolorization efficiency of 98% was obtained in sample FRU200 (with 3 g/L fructose added based on 3 g/L yeast extract), which was 21% higher than that without fructose. Several intermediates with low molecular weight generated in sample FRU200 and different metabolic pathways were deduced. The bacterial community structure significantly changed due to fructose addition. Label-free quantitative proteomic approach suggested that several up-regulated proteins in sample FRU200 might play essential roles during the degradation. Furthermore, the mechanisms of RB5 degradation by proteins/enzymes of the dominant species in flora DDMZ1 were proposed. This work deepens our understanding of the molecular and ecological mechanism of fructose as co-metabolite enhancing the biodegradation of refractory organic pollutants by a natural bacterial flora.
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Affiliation(s)
- Qingyun Zhang
- Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Xuehui Xie
- Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
| | - Yanbiao Liu
- Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Xiulin Zheng
- Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China
| | - Yiqin Wang
- Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China
| | - Junhao Cong
- Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China
| | - Chengzhi Yu
- Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China
| | - Na Liu
- School of Environment and Surveying Engineering, Suzhou University, Suzhou, Anhui 234000, China
| | - Jianshe Liu
- Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Wolfgang Sand
- Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China; Institute of Biosciences, Freiberg University of Mining and Technology, Freiberg 09599, Germany; Biofilm Centre, University Duisburg-Essen, Essen, Germany
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Suzuki H. Remarkable diversification of bacterial azoreductases: primary sequences, structures, substrates, physiological roles, and biotechnological applications. Appl Microbiol Biotechnol 2019; 103:3965-3978. [PMID: 30941462 DOI: 10.1007/s00253-019-09775-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/13/2019] [Accepted: 03/15/2019] [Indexed: 12/12/2022]
Abstract
Azoreductases reductively cleave azo linkages by using NAD(P)H as an electron donor. The enzymes are widely found in bacteria and act on numerous azo dyes, which allow various unique applications. This review describes primary amino acid sequences, structures, substrates, physiological roles, and biotechnological applications of bacterial azoreductases to discuss their remarkable diversification. According to primary sequences, azoreductases were classified phylogenetically into four main clades. Most members of clades I-III are flavoproteins, whereas clade IV members include flavin-free azoreductases. Clades I and II prefer NADPH and NADH, respectively, as electron donors, whereas other members generally use both. Several enzymes formed no clades; moreover, some bacteria produce azoreductases with longer primary structures than those hitherto identified, which implies further diversification of bacterial azoreductases. The crystal structures commonly reveal the Rossmann folds; however, ternary structures are moderately varied with different quaternary conformation. Although physiological roles are obscure, several azoreductases have been shown to act on metabolites such as flavins, quinones, and metal ions more efficiently than on azo dyes. Considering that many homologs exclusively act on these metabolites, it is possible that azoreductases are actually side activities of versatile reductases that act on various substrates with different specificities. In parallel, this idea raises the possibility that homologous enzymes, even if these are already defined as other types of reductases, widely harbor azoreductase activities. Although azoreductases for which their genes have been identified are not abundant, it may be simple to identify azoreductases of biotechnological importance that have novel substrate specificities.
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Affiliation(s)
- Hirokazu Suzuki
- Faculty of Engineering, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan. .,Center for Research on Green Sustainable Chemistry, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan.
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6
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Cloning and characterization of a Flavin-free oxygen-insensitive azoreductase from Klebsiella oxytoca GS-4-08. Biotechnol Lett 2019; 41:371-378. [DOI: 10.1007/s10529-019-02647-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 01/09/2019] [Indexed: 10/27/2022]
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Wang PT, Song YH, Fan HC, Yu L. Bioreduction of azo dyes was enhanced by in-situ biogenic palladium nanoparticles. BIORESOURCE TECHNOLOGY 2018; 266:176-180. [PMID: 29966927 DOI: 10.1016/j.biortech.2018.06.079] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 06/20/2018] [Accepted: 06/23/2018] [Indexed: 05/24/2023]
Abstract
Biogenic nanoparticles are promising materials for their green synthesis method and good performance in stimulation on reduction of environmental contaminants. In this study, Pd(0) nanoparticles (bio-Pd) were generated by Klebsiella oxytoca GS-4-08 in fermentative condition and in-situ improved the azo dye reduction. The bio-Pd was mainly located on cell membrane with a size range of 5-20 nm by TEM and XRD data analyses. Anthraquinone-2-disulfonate (AQS) greatly increased the reduction rate of Pd(II) with a reduction efficiency as high as 96.54 ± 0.23% in 24 h. The quinone respiration theory, glucose metabolism and the biohydrogen pathway were used to explain the enhancement mechanism of the in-situ generated bio-Pd on azo dye reduction. These results indicate that the in-situ generated bio-Pd by K. oxytoca strain is efficient for azo dye reduction without complex preparation processes, which is of great significance for the removal and subsequent safe disposal of hazardous environmental compounds.
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Affiliation(s)
- Peng-Tao Wang
- Department of Environmental Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Yu-Hang Song
- Department of Environmental Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Hong-Cheng Fan
- Department of Environmental Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Lei Yu
- Department of Environmental Engineering, Nanjing Forestry University, Nanjing 210037, China; Department of Microbiology, University of Massachusetts Amherst, Amherst, MA 01003, USA.
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Zhu Y, Xu J, Cao X, Cheng Y. Characterization of functional microbial communities involved in different transformation stages in a full-scale printing and dyeing wastewater treatment plant. Biochem Eng J 2018. [DOI: 10.1016/j.bej.2018.05.026] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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9
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Xiao X, Li TT, Lu XR, Feng XL, Han X, Li WW, Li Q, Yu HQ. A simple method for assaying anaerobic biodegradation of dyes. BIORESOURCE TECHNOLOGY 2018; 251:204-209. [PMID: 29277051 DOI: 10.1016/j.biortech.2017.12.052] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 12/14/2017] [Accepted: 12/17/2017] [Indexed: 06/07/2023]
Abstract
Anaerobic dye degradation is usually assayed using serum vials, which is time-consuming and costly. In this work, a simple method was established for real-time nondestructive assay of dye biodegradation using 96-well microtiter plates with petrolatum oil to avoid the volatilization and high transmittance transparent tape to prevent the permeation of oxygen. With the anaerobic degradation of methyl red and amaranth by Shewanella oneidensis MR-1, this assay method was verified. Further experiments revealed that blocking Mtr pathway had no substantial effect on the degradation of methyl red and dose of riboflavin also failed to promote the degradation of methyl red. On the contrary, the anaerobic degradation of amaranth depended mainly on the electron transmembrane transfer through Mtr pathway. Our work clearly indicates that Mtr pathway had different effects on intra- and extra-cellular degradation of azo dyes by S. oneidensis MR-1. Such a developed method is helpful for investigating anaerobic dye decolorization.
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Affiliation(s)
- Xiang Xiao
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China
| | - Ting-Ting Li
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Xue-Rong Lu
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Xiao-Li Feng
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Xue Han
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Wen-Wei Li
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China
| | - Qian Li
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Han-Qing Yu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China.
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Simultaneous Decolorization and Biohydrogen Production from Xylose by Klebsiella oxytoca GS-4-08 in the Presence of Azo Dyes with Sulfonate and Carboxyl Groups. Appl Environ Microbiol 2017; 83:AEM.00508-17. [PMID: 28283518 DOI: 10.1128/aem.00508-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 03/02/2017] [Indexed: 11/20/2022] Open
Abstract
Biohydrogen production from the pulp and paper effluent containing rich lignocellulosic material could be achieved by the fermentation process. Xylose, an important hemicellulose hydrolysis product, is used less efficiently as a substrate for biohydrogen production. Moreover, azo dyes are usually added to fabricate anticounterfeiting paper, which further increases the complexity of wastewater. This study reports that xylose could serve as the sole carbon source for a pure culture of Klebsiella oxytoca GS-4-08 to achieve simultaneous decolorization and biohydrogen production. With 2 g liter-1 of xylose as the substrate, a maximum xylose utilization rate (URxyl) and a hydrogen molar yield (HMY) of 93.99% and 0.259 mol of H2 mol of xylose-1, respectively, were obtained. Biohydrogen kinetics and electron equivalent (e- equiv) balance calculations indicated that methyl red (MR) penetrates and intracellularly inhibits both the pentose phosphate pathway and pyruvate fermentation pathway, while methyl orange (MO) acted independently of the glycolysis and biohydrogen pathway. The data demonstrate that biohydrogen pathways in the presence of azo dyes with sulfonate and carboxyl groups were different, but the azo dyes could be completely reduced during the biohydrogen production period in the presence of MO or MR. The feasibility of hydrogen production from industrial pulp and paper effluent by the strain if the xylose is sufficient was also proved and was not affected by toxic substances which usually exist in such wastewater, except for chlorophenol. This study offers a promising energy-recycling strategy for treating pulp and paper wastewaters, especially for those containing azo dyes.IMPORTANCE The pulp and paper industry is a major industry in many developing countries, and the global market of pulp and paper wastewater treatment is expected to increase by 60% between 2012 and 2020. Such wastewater contains large amounts of refractory contaminants, such as lignin, whose reclamation is considered economically crucial and environmentally friendly. Furthermore, azo dyes are usually added in order to fabricate anticounterfeiting paper, which further increases the complexity of the pulp and paper wastewater. This work may offer a better understanding of biohydrogen production from xylose in the presence of azo dyes and provide a promising energy-recycling method for treating pulp and paper wastewater, especially for those containing azo dyes.
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A novel Fe(III) dependent bioflocculant from Klebsiella oxytoca GS-4-08: culture conditions optimization and flocculation mechanism. Sci Rep 2016; 6:34980. [PMID: 27713559 PMCID: PMC5054519 DOI: 10.1038/srep34980] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 09/22/2016] [Indexed: 11/08/2022] Open
Abstract
In this work, the effect of cultivation factors on the flocculation efficiency (FE) of bioflocculant P-GS408 from Klebsiella oxytoca was optimized by the response surface methodology. The most significant factor, i.e. culture time, was determined by gray relational analysis. A total of 240 mg of purified P-GS408 was prepared from 1 liter of culture solution under the optimal conditions. GC-MS analysis results indicated that the polysaccharide of P-GS408 mainly contains Rhamnose and Galactose, and the existence of abundant hydroxyl, carboxyl and amino groups was evidenced by FTIR and XPS analyses. With the aid of Fe3+, the FE of kaolin solution by P-GS408 could achieve 99.48% in ten minutes. Functional groups of polysaccharide were involved in the first adsorption step and the zeta potential of kaolin solution changed from -39.0 mV to 43.4 mV in the presence of Fe3+ and P-GS408. Three-dimensional excitation-emission (EEM) fluorescence spectra demonstrates that the trivalent Fe3+ and Al3+ can bind efficiently with P-GS408, while those univalent and divalent cations cannot. With the help of SEM images, FTIR, zeta potential and EEM spectra, we proposed the P-GS408 flocculation mechanism, which consists of coordination bond combination, charge neutrality, adsorption and bridging, and net catching.
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12
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Enhanced reduction of Fe(III) oxides and methyl orange by Klebsiella oxytoca in presence of anthraquinone-2-disulfonate. Appl Microbiol Biotechnol 2016; 100:4617-25. [DOI: 10.1007/s00253-016-7281-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 12/27/2015] [Indexed: 10/22/2022]
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Decolorization characteristics of a newly isolated salt-tolerant Bacillus sp. strain and its application for azo dye-containing wastewater in immobilized form. Appl Microbiol Biotechnol 2015; 99:9277-87. [PMID: 26175104 DOI: 10.1007/s00253-015-6798-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 06/22/2015] [Accepted: 06/24/2015] [Indexed: 10/23/2022]
Abstract
Strain CICC 23870 capable of decolorization of various azo dyes under high saline conditions was isolated from saline-alkali soil. The oxygen-insensitive azoreductase in crude extracts exhibited a wide substrate adaptively in the presence of NADH as a cofactor. The decolorization process by free cells followed first-order kinetics, with a high Methyl Orange (MO) tolerance concentration up to 100 mg l(-1) estimated by Haldane model. The average decolorization rate of free cell system was 26.30 mg g(-1) h(-1) at initial MO concentration of 32.7 mg l(-1). However, the values for the systems of immobilized cells (4 mm) in alginate, alginate and nano-TiO2, and alginate and powered activated carbon (PAC) were 6.83, 4.64, and 11.34 mg g(-1) h(-1), respectively. The effective diffusion factors in the tree different matrices were calculated by diffusion-based mathematic model. The diffusion step controls the overall decolorization rate, and the effective diffusion coefficients varied with internal structure of the bead matrices. The diffusion coefficients were increased from 4.98 × 10(-9) to 2.25 × 10(-8) cm(2) s(-1) when PAC was added, but decreased to 6.62 × 10(-10) cm(2) s(-1) when nano-TiO2 was added. The immobilized matrices could be reused for at least three cycles but with a decreased decolorization rate, possibly due to the breakage of beads at the end of each cycle, which led to the loss of immobilized bacteria.
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