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Wang W, Xue J, You J, Han H, Qi H, Wang X. Effect of composite amendments on physicochemical properties of copper tailings repaired by herbaceous plants. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:19790-19802. [PMID: 36241833 DOI: 10.1007/s11356-022-23606-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 10/09/2022] [Indexed: 06/16/2023]
Abstract
Phytoremediation is considered to be the most environmentally friendly green restoration technology for dealing with mine waste. Adding amendments can improve the substrate environment for plant growth and enhance remediation efficiency. Herbaceous plants have become the preferred species for vegetation restoration in abandoned mines because of their fast greening and simple management. After 8 weeks of pot experiments in the early stage, it was shown that the plant height and fresh weight of the plants treated with 5% conditioner and 0.5% straw (C2S2) were significantly higher than those of other treatments. Considering that, in this paper, to explore the effect of composite amendments on physicochemical properties of copper tailings repaired by herbaceous plants, the untreated copper tailings were employed as the control group, whereas copper tailings repaired by ryegrass (Lolium perenne L.), vetiver grass (Chrysopogon zizanioides L.), and tall fescue (Festuca arundinacea) with or without conditioners and straw combination into the compound amendments were taken separately as the test group. After 6 months of planting, the pH, electrical conductivity, water content, available potassium, organic matter, total nitrogen, and available phosphorus in the main physical and chemical properties of copper tailings in each experimental area were analyzed. The results showed that the electrical conductivity, organic matter, and total nitrogen content of copper tailings were improved to a certain extent by planting plants without treatment. Meanwhile, compared with the control group, all indexes of planting plants showed an upward trend after adding composite amendments. Among them, pH, water content, and available potassium content of copper tailings were enhanced more obviously. Furthermore, as discovered from the gray correlation analysis results, vetiver grass planted with composite amendments has the best comprehensive effect of improving the physicochemical properties of copper tailings, followed by tall fescue and ryegrass.
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Affiliation(s)
- Weiwei Wang
- School of Energy and Mechanical Engineering, Jiangxi University of Science and Technology, Nanchang, 330013, Jiangxi, China
| | - Jinchun Xue
- School of Energy and Mechanical Engineering, Jiangxi University of Science and Technology, Nanchang, 330013, Jiangxi, China.
| | - Jiajia You
- School of Energy and Mechanical Engineering, Jiangxi University of Science and Technology, Nanchang, 330013, Jiangxi, China
| | - Huaqin Han
- School of Energy and Mechanical Engineering, Jiangxi University of Science and Technology, Nanchang, 330013, Jiangxi, China
| | - Hui Qi
- School of Energy and Mechanical Engineering, Jiangxi University of Science and Technology, Nanchang, 330013, Jiangxi, China
| | - Xiaojuan Wang
- School of Energy and Mechanical Engineering, Jiangxi University of Science and Technology, Nanchang, 330013, Jiangxi, China
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Sahu R, Meghavarnam AK, Janakiraman S. Evaluation of acrylamide production by Rhodococcus rhodochrous (RS-6) cells immobilized in agar matrix. J Appl Microbiol 2021; 132:1978-1989. [PMID: 34564923 DOI: 10.1111/jam.15303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 09/03/2021] [Accepted: 09/10/2021] [Indexed: 11/29/2022]
Abstract
AIMS The efficiency of acrylamide production was examined with immobilized cells of Rhodococcus rhodochrous (RS-6) containing NHase. METHODS AND RESULTS Different entrapment matrices such as agar, alginate and polyacrylamide were used. Various immobilization parameters like agar concentration, cell concentration and reaction conditions affecting the bioconversion process using suitable matrices were determined. The cells immobilized with agar matrix were found to be most effective for acrylonitrile conversion. The bioconversion was more efficient in beads prepared with 2% agar and 5% (v/v) cell concentration. The entire conversion of acrylonitrile to acrylamide with agar entrapped cells was achieved in 120 min at 15°C. The agar entrapped R. rhodochrous (RS-6) cells exhibited 8% (w/v) tolerance to acrylonitrile and 35% tolerance to acrylamide. The immobilized cells also retained 50% of its conversion ability up to seven cycles. The laboratory-scale (1 L) production resulted in 466 g L-1 accumulation of acrylamide in 16 h. CONCLUSIONS The cells immobilized in agar showed better stability and biocatalytic properties and increased reusability potential. SIGNIFICANCE AND IMPACT OF THE STUDY The agar-immobilized Rhodococcus rhodochrous (RS-6) cells showed enhanced tolerance for both the substrate and product and is economical for the large-scale production of acrylamide.
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Affiliation(s)
- Ruchi Sahu
- Department of Microbiology and Biotechnology, Bangalore University, Bangalore, India
| | | | - Savitha Janakiraman
- Department of Microbiology and Biotechnology, Bangalore University, Bangalore, India
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Wu Z, Zhang Z, Cai S, Zheng R, Zheng Y. High-level expression of nitrile hydratase from Pantoea sp. At-9b in Escherichia coli. Process Biochem 2021. [DOI: 10.1016/j.procbio.2020.11.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Cheng Z, Lan Y, Guo J, Ma D, Jiang S, Lai Q, Zhou Z, Peplowski L. Computational Design of Nitrile Hydratase from Pseudonocardia thermophila JCM3095 for Improved Thermostability. Molecules 2020; 25:molecules25204806. [PMID: 33086715 PMCID: PMC7587978 DOI: 10.3390/molecules25204806] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/08/2020] [Accepted: 10/16/2020] [Indexed: 11/16/2022] Open
Abstract
High thermostability and catalytic activity are key properties for nitrile hydratase (NHase, EC 4.2.1.84) as a well-industrialized catalyst. In this study, rational design was applied to tailor the thermostability of NHase from Pseudonocardia thermophila JCM3095 (PtNHase) by combining FireProt server prediction and molecular dynamics (MD) simulation. Site-directed mutagenesis of non-catalytic residues provided by the rational design was subsequentially performed. The positive multiple-point mutant, namely, M10 (αI5P/αT18Y/αQ31L/αD92H/βA20P/βP38L/βF118W/βS130Y/βC189N/βC218V), was obtained and further analyzed. The Melting temperature (Tm) of the M10 mutant showed an increase by 3.2 °C and a substantial increase in residual activity of the enzyme at elevated temperatures was also observed. Moreover, the M10 mutant also showed a 2.1-fold increase in catalytic activity compared with the wild-type PtNHase. Molecular docking and MD simulations demonstrated better substrate affinity and improved thermostability for the mutant.
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Affiliation(s)
- Zhongyi Cheng
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (Z.C.); (Y.L.); (J.G.); (D.M.); (S.J.); (Q.L.)
| | - Yao Lan
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (Z.C.); (Y.L.); (J.G.); (D.M.); (S.J.); (Q.L.)
| | - Junling Guo
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (Z.C.); (Y.L.); (J.G.); (D.M.); (S.J.); (Q.L.)
| | - Dong Ma
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (Z.C.); (Y.L.); (J.G.); (D.M.); (S.J.); (Q.L.)
| | - Shijin Jiang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (Z.C.); (Y.L.); (J.G.); (D.M.); (S.J.); (Q.L.)
| | - Qianpeng Lai
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (Z.C.); (Y.L.); (J.G.); (D.M.); (S.J.); (Q.L.)
| | - Zhemin Zhou
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (Z.C.); (Y.L.); (J.G.); (D.M.); (S.J.); (Q.L.)
- Jiangnan University (Rugao) Food Biotechnology Research Institute, Rugao 226500, China
- Correspondence: (Z.Z.); (L.P.)
| | - Lukasz Peplowski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
- Correspondence: (Z.Z.); (L.P.)
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Sahu R, Meghavarnam AK, Janakiraman S. Response surface methodology: An effective optimization strategy for enhanced production of nitrile hydratase (NHase) by Rhodococcus rhodochrous (RS-6). Heliyon 2020; 6:e05111. [PMID: 33088939 PMCID: PMC7560586 DOI: 10.1016/j.heliyon.2020.e05111] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/26/2020] [Accepted: 09/15/2020] [Indexed: 12/15/2022] Open
Abstract
Nitrile hydratase is an enzyme which catalyze the hydration of nitriles into amide and their role as catalysts for acrylamide production in industries are well known. The present study aims at statistically optimizing physiological and nutritional parameters for NHase production from Rhodococcus rhodochrous (RS-6). The effect of incubation period, temperature, pH, carbon and nitrogen sources on the production of NHase was investigated by one factor at a time strategy. Further optimization process was carried out by response surface methodology for studying the interactive effect of these variables using central composite design. The optimized levels of variables obtained by statistical analysis were: incubation period 48 h, temperature 33 °C, pH 7.0, glycerol 1% and urea 0.75%, which resulted in maximum NHase production. The results of ANOVA were significant with the F-value of the model being 296.78, value of R 2 is 0.9983 and the lack of fit test was not significant. The contour and response surface plots showed significant interaction between the variables. The NHase yield was enhanced up to 6.22 fold by statistical optimization using RSM. Thus, the developed experimental design is effective towards process optimization for NHase production from R. rhodochrous (RS-6).
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Affiliation(s)
- Ruchi Sahu
- Department of Microbiology and Biotechnology, Bangalore University, 560056, Bangalore, Karnataka, India
| | | | - Savitha Janakiraman
- Department of Microbiology and Biotechnology, Bangalore University, 560056, Bangalore, Karnataka, India
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Cheng Z, Xia Y, Zhou Z. Recent Advances and Promises in Nitrile Hydratase: From Mechanism to Industrial Applications. Front Bioeng Biotechnol 2020; 8:352. [PMID: 32391348 PMCID: PMC7193024 DOI: 10.3389/fbioe.2020.00352] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 03/30/2020] [Indexed: 12/21/2022] Open
Abstract
Nitrile hydratase (NHase, EC 4.2.1.84) is one type of metalloenzyme participating in the biotransformation of nitriles into amides. Given its catalytic specificity in amide production and eco-friendliness, NHase has overwhelmed its chemical counterpart during the past few decades. However, unclear catalytic mechanism, low thermostablity, and narrow substrate specificity limit the further application of NHase. During the past few years, numerous studies on the theoretical and industrial aspects of NHase have advanced the development of this green catalyst. This review critically focuses on NHase research from recent years, including the natural distribution, gene types, posttranslational modifications, expression, proposed catalytic mechanism, biochemical properties, and potential applications of NHase. The developments of NHase described here are not only useful for further application of NHase, but also beneficial for the development of the fields of biocatalysis and biotransformation.
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Affiliation(s)
| | | | - Zhemin Zhou
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
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Sahu R, Meghavarnam AK, Janakiraman S. A simple, efficient and rapid screening technique for differentiating nitrile hydratase and nitrilase producing bacteria. ACTA ACUST UNITED AC 2019; 24:e00396. [PMID: 31799145 PMCID: PMC6881679 DOI: 10.1016/j.btre.2019.e00396] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 11/06/2019] [Accepted: 11/07/2019] [Indexed: 01/21/2023]
Abstract
A rapid dye based plate screening method for nitrile hydrolyzing enzymes. Method identifies the end products of nitrile hydrolyzing enzymes. The method differentiates between nitrile hydratase and nitrilase producing bacteria. A potential NHase producing bacterial strain was identified as Rhodococcus rhodochrous.
Nitrile hydrolyzing enzymes catalyze the hydration of nitrile compounds to corresponding amides and acids. Bacteria, isolated from soil samples were screened for nitrile hydrolyzing enzymes by simple dye based 96 well plate and nesslerization method. Bromothymol blue was used as an indicator for the detection of amides and acids based on colour change of the indicator dye from blue to dark green or yellow. The screening assay also differentiates between nitrile hydratase (NHase) and nitrilase producing bacteria. Among the 108 bacterial strains screened for enzyme activity, six strains were positive for NHase activity and eleven strains were positive for nitrilase activity based on their ability to degrade acrylonitrile into products. The strain showing maximum NHase activity in quantitative assay was identified as Rhodococcus rhodochrous. The modified method developed by us would be useful for rapid screening of nitrile degrading bacteria potent for acrylamide/acrylic acid production when acrylonitrile is supplied as substrate.
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Affiliation(s)
- Ruchi Sahu
- Department of Microbiology and Biotechnology, Bangalore University, 560056, Bangalore, Karnataka, India
| | | | - Savitha Janakiraman
- Department of Microbiology and Biotechnology, Bangalore University, 560056, Bangalore, Karnataka, India
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Singh R, Pandey D, Devi N, Chand D. Bench scale production of butyramide using free and immobilized cells of Bacillus sp. APB-6. Bioprocess Biosyst Eng 2018; 41:1225-1232. [DOI: 10.1007/s00449-018-1951-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 05/04/2018] [Indexed: 11/29/2022]
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