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Wang L, Yi Z, Zhang P, Xiong Z, Zhang G, Zhang W. Comprehensive strategies for microcystin degradation: A review of the physical, chemical, and biological methods and genetic engineering. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 365:121707. [PMID: 38968883 DOI: 10.1016/j.jenvman.2024.121707] [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: 02/22/2024] [Revised: 06/02/2024] [Accepted: 07/02/2024] [Indexed: 07/07/2024]
Abstract
Addressing the threat of harmful cyanobacterial blooms (CyanoHABs) and their associated microcystins (MCs) is crucial for global drinking water safety. In this review, we comprehensively analyze and compares the physical, chemical, and biological methods and genetic engineering for MCs degradation in aquatic environments. Physical methods, such as UV treatments and photocatalytic reactions, have a high efficiency in breaking down MCs, with the potential for further enhancement in performance and reduction of hazardous byproducts. Chemical treatments using chlorine dioxide and potassium permanganate can reduce MC levels but require careful dosage management to avoid toxic by-products and protect aquatic ecosystems. Biological methods, including microbial degradation and phytoremediation techniques, show promise for the biodegradation of MCs, offering reduced environmental impact and increased sustainability. Genetic engineering, such as immobilization of microcystinase A (MlrA) in Escherichia coli and its expression in Synechocystis sp., has proven effective in decomposing MCs such as MC-LR. However, challenges related to specific environmental conditions such as temperature variations, pH levels, presence of other contaminants, nutrient availability, oxygen levels, and light exposure, as well as scalability of biological systems, necessitate further exploration. We provide a comprehensive evaluation of MCs degradation techniques, delving into their practicality, assessing the environmental impacts, and scrutinizing their efficiency to offer crucial insights into the multifaceted nature of these methods in various environmental contexts. The integration of various methodologies to enhance degradation efficiency is vital in the field of water safety, underscoring the need for ongoing innovation.
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Affiliation(s)
- Long Wang
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, People's Republic of China.
| | - Zhuoran Yi
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, People's Republic of China.
| | - Peng Zhang
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, People's Republic of China.
| | - Zhu Xiong
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, People's Republic of China.
| | - Gaosheng Zhang
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, People's Republic of China.
| | - Wei Zhang
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, People's Republic of China.
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Santos AA, Garrute FV, Magalhães VF, Pacheco ABF. Microcystin removal by microbial communities from a coastal lagoon: Influence of abiotic factors, bacterioplankton composition and estimated functions. HARMFUL ALGAE 2024; 135:102646. [PMID: 38830712 DOI: 10.1016/j.hal.2024.102646] [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: 12/11/2023] [Revised: 03/27/2024] [Accepted: 05/13/2024] [Indexed: 06/05/2024]
Abstract
Toxic cyanobacterial blooms present a substantial risk to public health due to the production of secondary metabolites, notably microcystins (MCs). Microcystin-LR (MC-LR) is the most prevalent and toxic variant in freshwater. MCs resist conventional water treatment methods, persistently impacting water quality. This study focused on an oligohaline shallow lagoon historically affected by MC-producing cyanobacteria, aiming to identify bacteria capable of degrading MC and investigating the influence of environmental factors on this process. While isolated strains did not exhibit MC degradation, microbial assemblages directly sourced from lagoon water removed MC-LR within seven days at 25 ºC and pH 8.0. The associated bacterial community demonstrated an increased abundance of bacterial taxa assigned to Methylophilales, and also Rhodospirillales and Rhodocyclales to a lesser extent. However, elevated atmospheric temperatures (45 ºC) and acidification (pH 5.0 and 3.0) hindered MC-LR removal, indicating that extreme environmental changes could contribute to prolonged MC persistence in the water column. This study highlights the importance of considering environmental conditions in order to develop strategies to mitigate cyanotoxin contamination in aquatic ecosystems.
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Affiliation(s)
- Allan A Santos
- Laboratory of Ecophysiology and Toxicology of Cyanobacteria, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
| | - Felipe V Garrute
- Laboratory of Ecophysiology and Toxicology of Cyanobacteria, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; Ultrasound Laboratory, Biomedical Engineering Program-COPPE, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; Biological Physics Laboratory, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Valéria F Magalhães
- Laboratory of Ecophysiology and Toxicology of Cyanobacteria, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ana Beatriz F Pacheco
- Biological Physics Laboratory, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
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3
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Yang S, Zuo J, Grossart HP, Dai G, Liu J, Song L, Gan N. Evaluating microcystinase A-based approach on microcystins degradation during harvested cyanobacterial blooms. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 348:123878. [PMID: 38548158 DOI: 10.1016/j.envpol.2024.123878] [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: 02/21/2024] [Revised: 03/21/2024] [Accepted: 03/25/2024] [Indexed: 04/07/2024]
Abstract
Addressing notorious and worldwide Microcystis blooms, mechanical algae harvesting is an effective emergency technology for bloom mitigation and removal of nutrient loads in waterbodies. However, the absence of effective methods for removal of cyanobacterial toxins, e.g., microcystins (MCs), poses a challenge to recycle the harvested Microcystis biomass. In this study, we therefore introduced a novel approach, the "captured biomass-MlrA enzymatic MC degradation", by enriching microcystinase A (MlrA) via fermentation and spraying it onto salvaged Microcystis slurry to degrade all MCs. After storing the harvested Microcystis slurry, a rapid release of extracellular MCs occurred within the initial 8 h, reaching a peak concentration of 5.33 μg/mL at 48 h during the composting process. Upon spraying the recombinant MlrA crude extract (about 3.36 U) onto the Microcystis slurry in a ratio of 0.1% (v/v), over 95% of total MCs were degraded within a 24-h period. Importantly, we evaluated the reliability and safety of using MlrA extracts to degrade MCs. Results showed that organic matter/nutrient contents, e.g. soluble proteins, polysaccharides, phycocyanin and carotenoids, were not significantly altered. Furthermore, the addition of MlrA extracts did not significantly change the bacterial community composition and diversity in the Microcystis slurry, indicating that the MlrA extracts did not increase the risk of pathogenic bacteria. Our study provides an effective and promising method for the pre-treatment of harvested Microcystis biomass, highlighting an ecologically sustainable framework for addressing Microcystis blooms.
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Affiliation(s)
- Siyu Yang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China; University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Jun Zuo
- National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, Zhejiang Provincial Key Lab for Water Environment and Marine Biological Resources Protection, Institute for Eco-Environmental Research of Sanyang Wetland, Wenzhou University, Wenzhou, 325035, China.
| | - Hans-Peter Grossart
- Department of Plankton and Microbial Ecology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries IGB, Stechlin, Germany; Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Guofei Dai
- Jiangxi Academy of Water Science and Engineering, Nanchang, 330029, China
| | - Jin Liu
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Lirong Song
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Nanqin Gan
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
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Teng J, Song M, Xu Q, Zou Q, Zhang H, Yin C, Liu X, Liu Y, Yan H. Purification and Activity of the Second Recombinant Enzyme for Biodegrading Linearized Microcystins by Sphingopyxis sp. USTB-05. Toxins (Basel) 2023; 15:494. [PMID: 37624251 PMCID: PMC10467064 DOI: 10.3390/toxins15080494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/26/2023] [Accepted: 08/02/2023] [Indexed: 08/26/2023] Open
Abstract
Hepatotoxic microcystins (MCs) are produced and released by the harmful bloom-forming cyanobacteria, which severely threaten drinking water safety and human health due to their high toxicity, widespread distribution, and structural stability. The linearized microcystinase (MlrB) further hydrolyses the poisonous linearized MCs produced by the microcystinase-catalysed MCs to form tetrapeptides. Here, the purification and activity of MlrB were investigated. The results showed that the linearized products generated by 12.5 mg/L MC-LR and MC-RR were removed by purified recombinant MlrB at a protein concentration of 1 mg/L within 30 min. The high catalytic activity of MlrB can be obtained via heterologous expression and affinity purification, which lays the foundation for further studies on the properties and mechanism of MCs biodegradation enzymes.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Hai Yan
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China; (J.T.)
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Cai D, Wei J, Huang F, Feng H, Peng T, Luo J, Yang F. The detoxification activities and mechanisms of microcystinase towards MC-LR. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 236:113436. [PMID: 35367885 DOI: 10.1016/j.ecoenv.2022.113436] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/13/2022] [Accepted: 03/16/2022] [Indexed: 06/14/2023]
Abstract
Microcystins (MCs) are the most common and toxic cyanotoxins that are hazardous to human health and ecosystems. Microcystinase is the enzyme in charge of the initial step in the biodegradation of MCs. The characterization, application conditions, and detoxification mechanisms of microcystinase from an indigenous bacterium Sphingopyxis sp. YF1 towards MC-LR were investigated in the current study. The microcystinase gene of strain YF1 was most similar to Sphingomonas sp. USTB-05 and contained a CAAX-family conversed abortive Infection (ABI) domain. The microcystinase was successful obtained and purified by overexpression in Escherichia coli. The highest degradation rate of MC-LR was 1.0 μg/mL/min under the optimal condition of 30 ℃, pH 7, 20 μg/mL MC-LR, and 400 μg/mL microcystinase. The MC-degrading product was identified as linearized MC-LR, which possessed a much lower inhibitory activity against protein phosphatase 2A than MC-LR. Microcystinase interacted with MC-LR via amino acid residues involved in through the formation of conventional Hydrogen Bond, Pi-Pi T-shapes, Van der Waals force, and so on. The optimal MC-degrading condition of pure microcystinase and its detoxification mechanisms against MC-LR were revealed. The toxicity of purified linearized MC-LR was explored for the first time. These findings suggest that pure microcystinase may efficiently detoxify MCs and it is promising in the bioremediation of MC-polluted environments.
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Affiliation(s)
- Danping Cai
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, University of South China, Hengyang, China.
| | - Jia Wei
- Xiangya School of Public Health, Central South University, Changsha, China.
| | - Feiyu Huang
- The First People's Hospital of Jingzhou, Jingzhou, China.
| | - Hai Feng
- Xiangya School of Public Health, Central South University, Changsha, China.
| | - Tangjian Peng
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, University of South China, Hengyang, China.
| | - Jiayou Luo
- Xiangya School of Public Health, Central South University, Changsha, China.
| | - Fei Yang
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, University of South China, Hengyang, China; Xiangya School of Public Health, Central South University, Changsha, China.
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Simultaneous Removal of the Freshwater Bloom-Forming Cyanobacterium Microcystis and Cyanotoxin Microcystins via Combined Use of Algicidal Bacterial Filtrate and the Microcystin-Degrading Enzymatic Agent, MlrA. Microorganisms 2021; 9:microorganisms9081594. [PMID: 34442673 PMCID: PMC8401626 DOI: 10.3390/microorganisms9081594] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/19/2021] [Accepted: 07/20/2021] [Indexed: 11/16/2022] Open
Abstract
Freshwater cyanobacterial blooms (e.g., Microcystis blooms) constitute a major global environmental problem because of their risks to public health and aquatic ecological systems. Current physicochemical treatments of toxic cyanobacteria cause the significant release of cyanotoxin microcystins from damaged cells. Biological control is a promising eco-friendly technology to manage harmful cyanobacteria and cyanotoxins. Here, we demonstrated an efficient biological control strategy at the laboratory scale to simultaneously remove Microcystis and microcystins via the combined use of the algicidal bacterial filtrate and the microcystin-degrading enzymatic agent. The algicidal indigenous bacterium Paenibacillus sp. SJ-73 was isolated from the sediment of northern Lake Taihu, China, and the microcystin-degrading enzymatic agent (MlrA) was prepared via the heterologous expression of the mlrA gene in the indigenous microcystin-degrading bacterium Sphingopyxis sp. HW isolated from Lake Taihu. The single use of a fermentation filtrate (5%, v/v) of Paenibacillus sp. SJ-73 for seven days removed the unicellular Microcystis aeruginosa PCC 7806 and the native colonial Microcystis strain TH1701 in Lake Taihu by 84% and 92%, respectively, whereas the single use of MlrA removed 85% of microcystins. Used in combination, the fermentation filtrate and MlrA removed Microcystis TH1701 and microcystins by 92% and 79%, respectively. The present biological control thus provides an important technical basis for the further development of safe, efficient, and effective measures to manage Microcystis blooms and microcystins in natural waterbodies.
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Bioinformatic analyses and enzymatic properties of microcystinase. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Dexter J, McCormick AJ, Fu P, Dziga D. Microcystinase - a review of the natural occurrence, heterologous expression, and biotechnological application of MlrA. WATER RESEARCH 2021; 189:116646. [PMID: 33246218 DOI: 10.1016/j.watres.2020.116646] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 11/01/2020] [Accepted: 11/14/2020] [Indexed: 06/11/2023]
Abstract
Microcystinase (MlrA) was first described in 1996. Since then MlrA peptidase activity has proven to be both the most efficient enzymatic process and the most specific catalyst of all known microcystins detoxification pathways. Furthermore, MlrA and the MlrABC degradation pathway are presently the only enzymatic processes with clear genetic and biochemical descriptions available for microcystins degradation, greatly facilitating modern applied genetics for any relevant technological development. Recently, there has been increasing interest in the potential of sustainable, biologically inspired alternatives to current industrial practice, with note that biological microcystins degradation is the primary detoxification process found in nature. While previous reviews have broadly discussed microbial biodegradation processes, here we present a review focused specifically on MlrA. Following a general overview, we briefly highlight the initial discovery and present understanding of the MlrABC degradation pathway, before discussing the genetic and biochemical aspects of MlrA. We then review the potential biotechnology applications of MlrA in the context of available literature with emphasis on the optimization of MlrA for in situ applications including (i) direct modulation of Mlr activity within naturally existing populations, (ii) bioaugmentation of systems with introduced biodegradative capacity via whole cell biocatalysts, and (iii) bioremediation via direct MlrA application.
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Affiliation(s)
- Jason Dexter
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 31-007 Kraków, Poland; Cyanoworks, LLC, 1771 Haskell Rd., Olean, NY 14760, USA.
| | - Alistair J McCormick
- SynthSys & Institute of Molecular Plant Sciences, School of Biological Sciences, King's Buildings, University of Edinburgh, EH9 3BF, UK.
| | - Pengcheng Fu
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, 58 Renmin Avenue, Meilan District, Haikou, Hainan Province, 570228 China.
| | - Dariusz Dziga
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 31-007 Kraków, Poland.
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Wang R, Li J, Li J. Functional and structural analyses for MlrC enzyme of Novosphingobium sp. THN1 in microcystin-biodegradation: Involving optimized heterologous expression, bioinformatics and site-directed mutagenesis. CHEMOSPHERE 2020; 255:126906. [PMID: 32387905 DOI: 10.1016/j.chemosphere.2020.126906] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 04/23/2020] [Accepted: 04/25/2020] [Indexed: 06/11/2023]
Abstract
Enzymatic function of MlrC from Novosphingobium sp. THN1 (i.e., THN1-MlrC) towards linearized microcystins (MCs) and structural/physic-chemical properties of MlrC enzyme deserved urgent research, and heterologous expression (HE) optimization for MlrC is yet to be solved. This study achieved HE of THN1-MlrC by rapid-efficiently constructing HE system, and revealed that THN1-MlrC can degrade linearized MC-LR and linearized MC-RR to produce Adda, providing direct evidence for catalytic function of THN-MlrC and its ecological implication in MC-detoxification. Consequently, to maximize THN1-MlrC expression for production and application, induction conditions for HE of THN1-MlrC was optimized as at 0.1 mM of isopropyl-β-D-thiogalactoside and 30 °C for 8 h, which could be widely applicable for heterologous production of other MlrC homologs. Using bioinformatics and site-mutation experiment, THN1-MlrC was evaluated as a cytoplasm-locating hydrophilic protein with theoretical isoelectric point of 5.57, and contained six verified active sites Glu39, His133, Asp167, His169, His191 and Asp332 in two domains of its 3D structure, among which Glu39, His133 and Asp332 were newly-discovered ones here. The Glu39, His133, Asp167, His169 and His191 gathered more closely in 3D structure than in amino acid sequence, while they and Asp332 surrounded protein center to constitute a potential active pocket for mediating linearized MCs degradation. Due to MlrC sequence homology and conservative active sites, structural/physic-chemical characteristics of THN1-MlrC presented in this study provided a helpful reference for other MlrC homologs of diverse bacteria. This study shed novel insights for functional-structural relationships of THN1-MlrC during MC-biodegradation, and was crucial for research and practical applications in MC-decontamination.
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Affiliation(s)
- Ruiping Wang
- College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China; Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing, 100193, China
| | - Jieming Li
- College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China; Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing, 100193, China.
| | - Ji Li
- College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China; Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing, 100193, China
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Liu H, Guo X, Liu L, Yan M, Li J, Hou S, Wan J, Feng L. Simultaneous Microcystin Degradation and Microcystis aeruginosa Inhibition with the Single Enzyme Microcystinase A. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:8811-8820. [PMID: 32463659 DOI: 10.1021/acs.est.0c02155] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Harmful Microcystis blooms (HMBs) seriously threaten the ecology of environments and human health. Microcystins (MCs) produced by Microcystis are powerful mediators of HMB induction and maintenance. In this study, microcystinase A (MlrA), an enzyme with MC-degrading ability, was successfully obtained at over 90% purity for the first time through overexpression in Escherichia coli K12 TB1. The obtained MlrA exhibited high stability at high temperature and under alkaline conditions, while also exhibiting a long half-life. MlrA selectively inhibited MC-producing Microcystis cultures, but had no effect on MC-nonproducing Synechocystis cultures. The inhibition mechanism of MlrA against Microcystis was investigated by evaluating the morphological and physiological characteristics of cultures. MlrA effectively degraded extracellular MCs and decreased the synthesis of intracellular MCs by causing downregulation of genes involved in the microcystin biosynthesis pathway. Concomitantly, MlrA inhibited Microcystis photosynthesis by causing the downregulated expression of important photosynthesis pathway genes and interrupting electron transport chain activities and pigment synthesis. Thus, MlrA achieved the inhibition of Microcystis growth by reducing its photosynthetic capacity and intracellular MC contents, while also degrading extracellular MCs. On the basis of these results, we propose a new paradigm to achieve the simultaneous removal of MCs and HMBs using the single enzyme characterized here.
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Affiliation(s)
- Honglin Liu
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Xiaoliang Guo
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Lei Liu
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Mingyue Yan
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Jiahui Li
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Shuyan Hou
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Jian Wan
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Lingling Feng
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
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Spoof L, Jaakkola S, Važić T, Häggqvist K, Kirkkala T, Ventelä AM, Kirkkala T, Svirčev Z, Meriluoto J. Elimination of cyanobacteria and microcystins in irrigation water-effects of hydrogen peroxide treatment. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:8638-8652. [PMID: 31907814 PMCID: PMC7048868 DOI: 10.1007/s11356-019-07476-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 12/19/2019] [Indexed: 06/10/2023]
Abstract
Cyanobacterial blooms pose a risk to wild and domestic animals as well as humans due to the toxins they may produce. Humans may be subjected to cyanobacterial toxins through many routes, e.g., by consuming contaminated drinking water, fish, and crop plants or through recreational activities. In earlier studies, cyanobacterial cells have been shown to accumulate on leafy plants after spray irrigation with cyanobacteria-containing water, and microcystin (MC) has been detected in the plant root system after irrigation with MC-containing water. This paper reports a series of experiments where lysis of cyanobacteria in abstracted lake water was induced by the use of hydrogen peroxide and the fate of released MCs was followed. The hydrogen peroxide-treated water was then used for spray irrigation of cultivated spinach and possible toxin accumulation in the plants was monitored. The water abstracted from Lake Köyliönjärvi, SW Finland, contained fairly low concentrations of intracellular MC prior to the hydrogen peroxide treatment (0.04 μg L-1 in July to 2.4 μg L-1 in September 2014). Hydrogen peroxide at sufficient doses was able to lyse cyanobacteria efficiently but released MCs were still present even after the application of the highest hydrogen peroxide dose of 20 mg L-1. No traces of MC were detected in the spinach leaves. The viability of moving phytoplankton and zooplankton was also monitored after the application of hydrogen peroxide. Hydrogen peroxide at 10 mg L-1 or higher had a detrimental effect on the moving phytoplankton and zooplankton.
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Affiliation(s)
- Lisa Spoof
- Åbo Akademi University, Faculty of Science and Engineering, Biochemistry, Tykistökatu 6A, 20520, Turku, Finland
| | - Sauli Jaakkola
- Pyhäjärvi Institute, Sepäntie 7, 27500, Kauttua, Finland
| | - Tamara Važić
- Faculty of Sciences, Department of Biology and Ecology, University of Novi Sad, Trg Dositeja Obradovića 2, Novi Sad, 21000, Serbia
| | - Kerstin Häggqvist
- Åbo Akademi University, Faculty of Science and Engineering, Biochemistry, Tykistökatu 6A, 20520, Turku, Finland
| | - Terhi Kirkkala
- Department of Chemistry, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland
| | | | - Teija Kirkkala
- Pyhäjärvi Institute, Sepäntie 7, 27500, Kauttua, Finland
| | - Zorica Svirčev
- Åbo Akademi University, Faculty of Science and Engineering, Biochemistry, Tykistökatu 6A, 20520, Turku, Finland
- Faculty of Sciences, Department of Biology and Ecology, University of Novi Sad, Trg Dositeja Obradovića 2, Novi Sad, 21000, Serbia
| | - Jussi Meriluoto
- Åbo Akademi University, Faculty of Science and Engineering, Biochemistry, Tykistökatu 6A, 20520, Turku, Finland.
- Faculty of Sciences, Department of Biology and Ecology, University of Novi Sad, Trg Dositeja Obradovića 2, Novi Sad, 21000, Serbia.
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The Effect of a Combined Hydrogen Peroxide-MlrA Treatment on the Phytoplankton Community and Microcystin Concentrations in a Mesocosm Experiment in Lake Ludoš. Toxins (Basel) 2019; 11:toxins11120725. [PMID: 31835838 PMCID: PMC6950535 DOI: 10.3390/toxins11120725] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/02/2019] [Accepted: 12/05/2019] [Indexed: 01/04/2023] Open
Abstract
Harmful cyanobacteria and their toxic metabolites constitute a big challenge for the production of safe drinking water. Microcystins (MC), chemically stable hepatotoxic heptapeptides, have often been involved in cyanobacterial poisoning incidents. A desirable solution for cyanobacterial management in lakes and ponds would eliminate both excess cyanobacteria and the MC that they potentially produce and release upon lysis. Hydrogen peroxide (H2O2) has recently been advocated as an efficient means of lysing cyanobacteria in lakes and ponds, however H2O2 (at least when used at typical concentrations) cannot degrade MC in environmental waters. Therefore, mesocosm experiments combining the cyanobacteria-lysing effect of H2O2 and the MC-degrading capacity of the enzyme MlrA were set up in the highly eutrophic Lake Ludoš (Serbia). The H2O2 treatment decreased the abundance of the dominant cyanobacterial taxa Limnothrix sp., Aphanizomenon flos-aquae, and Planktothrix agardhii. The intracellular concentration of MC was reduced/eliminated by H2O2, yet the reduction of the extracellular MC could only be accomplished by supplementation with MlrA. However, as H2O2 was found to induce the expression of mcyB and mcyE genes, which are involved in MC biosynthesis, the use of H2O2 as a safe cyanobacteriocide still requires further investigation. In conclusion, the experiments showed that the combined use of H2O2 and MlrA is promising in the elimination of both excess cyanobacteria and their MC in environmental waters.
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Xu Q, Fan J, Yan H, Ahmad S, Zhao Z, Yin C, Liu X, Liu Y, Zhang H. Structural basis of microcystinase activity for biodegrading microcystin-LR. CHEMOSPHERE 2019; 236:124281. [PMID: 31310980 DOI: 10.1016/j.chemosphere.2019.07.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 06/20/2019] [Accepted: 07/02/2019] [Indexed: 06/10/2023]
Abstract
Microcystinase (MlrA) catalyzes the first and most important biodegradation step of hepatotoxic microcystin-LR (MC-LR) produced and released from cyanobacterial cells, and the underlying catalytic mechanism is not completely understood yet. MlrA was postulated previously to be a metalloprotease with an active site of H260AIH263NE265, a variant of the common metal-binding motif of HEXXH. Through comparison with representative modes in HEXXH-containing metalloproteases, molecular dynamics simulation, homology modeling, and docking, the active sites of MlrA involved in the MC-LR biodegradation by Sphingomonas sp. USTB-05 were predicted. Site-directed mutants of MlrA were constructed for verification then. The results show that MlrA is likely not a metalloprotease, but a glutamate protease belonging to type II CAAX prenyl endopeptidases. Combined with the biodegradation of MC-LR by MlrA and its mutants, a complete enzymatic mechanism for MC-LR biodegradation by MlrA is proposed: Glu172 and His205 activate a water molecule facilitating a nucleophilic attack on the Adda-Arg peptide bond of MC-LR; Trp176 and Trp201 contact the carboxylate side chain of Glu172and, by raising its pKa potentially, accelerate the reaction rates; His260 and Asn264 (located in the previous postulated active center of H260AIH263NE265) function as an oxyanion hole to stabilize the transition states. This study reveals the enzymatic mechanism of MlrA for catalyzing MC-LR in both the representative modes and the experiments of site-directed mutagenesis.
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Affiliation(s)
- Qianqian Xu
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083, Beijing, China
| | - Jinhui Fan
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083, Beijing, China
| | - Hai Yan
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083, Beijing, China.
| | - Shahbaz Ahmad
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083, Beijing, China
| | - Zhenzhen Zhao
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083, Beijing, China
| | - Chunhua Yin
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083, Beijing, China
| | - Xiaolu Liu
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083, Beijing, China
| | - Yang Liu
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083, Beijing, China
| | - Haiyang Zhang
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083, Beijing, China.
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Silva MOD, Desmond P, Derlon N, Morgenroth E, Pernthaler J. Source Community and Assembly Processes Affect the Efficiency of Microbial Microcystin Degradation on Drinking Water Filtration Membranes. Front Microbiol 2019; 10:843. [PMID: 31057530 PMCID: PMC6482319 DOI: 10.3389/fmicb.2019.00843] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 04/02/2019] [Indexed: 01/14/2023] Open
Abstract
Microbial biofilms in gravity-driven membrane (GDM) filtration systems can efficiently degrade the cyanotoxin microcystin (MC), but it is unclear if this function depends on the presence of MC-producing cyanobacteria in the source water habitat. We assessed the removal of MC from added Microcystis aeruginosa biomass in GDMs fed with water from a lake with regular blooms of toxic cyanobacteria (ExpL) or from a stream without such background (ExpS). While initial MC removal was exclusively due to abiotic processes, significantly higher biological MC removal was observed in ExpL. By contrast, there was no difference in MC degradation capacity between lake and stream bacteria in separately conducted liquid enrichments on pure MC. Co-occurrence network analysis revealed a pronounced modularity of the biofilm communities, with a clear hierarchic distinction according to feed water origin and treatment type. Genotypes in the network modules associated with ExpS had significantly more links to each other, indicating that these biofilms had assembled from a more coherent source community. In turn, signals for stochastic community assembly were stronger in ExpL biofilms. We propose that the less "tightly knit" ExpL biofilm assemblages allowed for the better establishment of facultatively MC degrading bacteria, and thus for higher overall functional efficiency.
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Affiliation(s)
- Marisa O. D. Silva
- Limnological Station, Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Peter Desmond
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
- Institute of Environmental Engineering, ETH Zurich, Institute of Environmental Engineering, Zurich, Switzerland
| | - Nicolas Derlon
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Eberhard Morgenroth
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
- Institute of Environmental Engineering, ETH Zurich, Institute of Environmental Engineering, Zurich, Switzerland
| | - Jakob Pernthaler
- Limnological Station, Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
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15
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Ding Q, Liu K, Xu K, Sun R, Zhang J, Yin L, Pu Y. Further Understanding of Degradation Pathways of Microcystin-LR by an Indigenous Sphingopyxis sp. in Environmentally Relevant Pollution Concentrations. Toxins (Basel) 2018; 10:toxins10120536. [PMID: 30558170 PMCID: PMC6315713 DOI: 10.3390/toxins10120536] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 12/03/2018] [Accepted: 12/12/2018] [Indexed: 11/16/2022] Open
Abstract
Microcystin-LR (MC-LR) is the most widely distributed microcystin (MC) that is hazardous to environmental safety and public health, due to high toxicity. Microbial degradation is regarded as an effective and environment-friendly method to remove it, however, the performance of MC-degrading bacteria in environmentally relevant pollution concentrations of MC-LR and the degradation pathways remain unclear. In this study, one autochthonous bacterium, Sphingopyxis sp. m6 which exhibited high MC-LR degradation ability, was isolated from Lake Taihu, and the degrading characteristics in environmentally relevant pollution concentrations were demonstrated. In addition, degradation products were identified by utilizing the full scan mode of UPLC-MS/MS. The data illustrated that strain m6 could decompose MC-LR (1–50 μg/L) completely within 4 h. The degradation rates were significantly affected by temperatures, pH and MC-LR concentrations. Moreover, except for the typical degradation products of MC-LR (linearized MC-LR, tetrapeptide, and Adda), there were 8 different products identified, namely, three tripeptides (Adda-Glu-Mdha, Glu-Mdha-Ala, and Leu-MeAsp-Arg), three dipeptides (Glu-Mdha, Mdha-Ala, and MeAsp-Arg) and two amino acids (Leu, and Arg). To our knowledge, this is the first report of Mdha-Ala, MeAsp-Arg, and Leu as MC-LR metabolites. This study expanded microbial degradation pathways of MC-LR, which lays a foundation for exploring degradation mechanisms and eliminating the pollution of microcystins (MCs).
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Affiliation(s)
- Qin Ding
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education of China, School of Public Health, Southeast University, Nanjing 210009, China.
| | - Kaiyan Liu
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education of China, School of Public Health, Southeast University, Nanjing 210009, China.
| | - Kai Xu
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education of China, School of Public Health, Southeast University, Nanjing 210009, China.
| | - Rongli Sun
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education of China, School of Public Health, Southeast University, Nanjing 210009, China.
| | - Juan Zhang
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education of China, School of Public Health, Southeast University, Nanjing 210009, China.
| | - Lihong Yin
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education of China, School of Public Health, Southeast University, Nanjing 210009, China.
| | - Yuepu Pu
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education of China, School of Public Health, Southeast University, Nanjing 210009, China.
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16
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The Effect of Organic Carbon Addition on the Community Structure and Kinetics of Microcystin-Degrading Bacterial Consortia. WATER 2018. [DOI: 10.3390/w10111523] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Microcystin (MC), a hepatotoxin that is associated with cyanobacterial blooms in freshwater lakes, threatens the quality of drinking water resources. Biodegradation of MC using biofiltration is emerging as a cost-effective solution for drinking water treatment. This study reports isolation of five MC-degrading microbial consortia and investigation of their community structure and kinetics in the presence or absence of a readily-bioavailable organic carbon source. The results indicated that the presence of a bioavailable organic carbon source caused: (1) the proliferation of community members previously unobserved in each consortium cultured without ethanol; (2) a shift in abundance of representative taxa; (3) a fluctuation in genera affiliated with MC-biodegradation; and, (4) a unique response in simulated diversity among consortia. These changes to each microbial consortium were paralleled by a significant decline in MC degradation kinetics. Overall, this study highlights the importance of integrating environmental conditions into the design and operation of biofiltration systems for MC biodegradation.
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17
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Yang F, Guo J, Huang F, Massey IY, Huang R, Li Y, Wen C, Ding P, Zeng W, Liang G. Removal of Microcystin-LR by a Novel Native Effective Bacterial Community Designated as YFMCD4 Isolated from Lake Taihu. Toxins (Basel) 2018; 10:toxins10090363. [PMID: 30205544 PMCID: PMC6162702 DOI: 10.3390/toxins10090363] [Citation(s) in RCA: 27] [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: 08/07/2018] [Revised: 09/02/2018] [Accepted: 09/05/2018] [Indexed: 11/25/2022] Open
Abstract
Microcystin-LR (MC-LR) is the most toxic and frequently detected monocyclic heptapeptide hepatotoxin produced by cyanobacteria, which poses a great threat to the natural ecosystem and public health. It is very important to seek environment-friendly and cost-efficient methods to remove MC-LR in water. In this study, the MC-degrading capacities of a novel indigenous bacterial community designated as YFMCD4 and the influence of environmental factors including various temperatures, MC concentrations and pH on the MC-degrading activities were investigated utilizing high-performance liquid chromatography (HPLC). In addition, the MC-degrading mechanism of YFMCD4 was also studied using HPLC coupled with a mass spectrometry equipped with electrospray ionization interface (HPLC-ESI-MS). The data showed MC-LR was completely removed at the maximum rate of 0.5 µg/(mL·h) under the optimal condition by YFMCD4. Two pure bacterial strains Alcaligenes faecalis and Stenotrophomonas acidaminiohila were isolated from YFMCD4 degraded MC-LR at a slower rate. The MC-degrading rates of YFMCD4 were significantly affected by different temperatures, pH and MC-LR concentrations. Two intermediates of a tetrapeptide and Adda appeared in the degradation process. These results illustrate that the novel YFMCD4 is one of the highest effective MC-degrading bacterial community, which can completely remove MC-LR and possesses a significant potential to treat water bodies contaminated by MC-LR.
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Affiliation(s)
- Fei Yang
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, 110 Xiangya Road, Changsha 410078, China.
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health Southeast University, Nanjing 210009, China.
- Key laboratory of Hunan Province for Water Environment and Agriculture Product Safety, Central South University, Changsha 410083, China.
| | - Jian Guo
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, 110 Xiangya Road, Changsha 410078, China.
| | - Feiyu Huang
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, 110 Xiangya Road, Changsha 410078, China.
| | - Isaac Yaw Massey
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, 110 Xiangya Road, Changsha 410078, China.
| | - Ruixue Huang
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, 110 Xiangya Road, Changsha 410078, China.
| | - Yunhui Li
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health Southeast University, Nanjing 210009, China.
| | - Cong Wen
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, 110 Xiangya Road, Changsha 410078, China.
| | - Ping Ding
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, 110 Xiangya Road, Changsha 410078, China.
| | - Weiming Zeng
- Key Laboratory of Biometallurgy, Ministry of Education, School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China.
| | - Geyu Liang
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health Southeast University, Nanjing 210009, China.
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18
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Dexter J, Dziga D, Lv J, Zhu J, Strzalka W, Maksylewicz A, Maroszek M, Marek S, Fu P. Heterologous expression of mlrA in a photoautotrophic host - Engineering cyanobacteria to degrade microcystins. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 237:926-935. [PMID: 29454496 DOI: 10.1016/j.envpol.2018.01.071] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 01/15/2018] [Accepted: 01/21/2018] [Indexed: 05/08/2023]
Abstract
In this report, we establish proof-of-principle demonstrating for the first time genetic engineering of a photoautotrophic microorganism for bioremediation of naturally occurring cyanotoxins. In model cyanobacterium Synechocystis sp. PCC 6803 we have heterologously expressed Sphingopyxis sp. USTB-05 microcystinase (MlrA) bearing a 23 amino acid N-terminus secretion peptide from native Synechocystis sp. PCC 6803 PilA (sll1694). The resultant whole cell biocatalyst displayed about 3 times higher activity against microcystin-LR compared to a native MlrA host (Sphingomonas sp. ACM 3962), normalized for optical density. In addition, MlrA activity was found to be almost entirely located in the cyanobacterial cytosolic fraction, despite the presence of the secretion tag, with crude cellular extracts showing MlrA activity comparable to extracts from MlrA expressing E. coli. Furthermore, despite approximately 9.4-fold higher initial MlrA activity of a whole cell E. coli biocatalyst, utilization of a photoautotrophic chassis resulted in prolonged stability of MlrA activity when cultured under semi-natural conditions (using lake water), with the heterologous MlrA biocatalytic activity of the E. coli culture disappearing after 4 days, while the cyanobacterial host displayed activity (3% of initial activity) after 9 days. In addition, the cyanobacterial cell density was maintained over the duration of this experiment while the cell density of the E. coli culture rapidly declined. Lastly, failure to establish a stable cyanobacterial isolate expressing native MlrA (without the N-terminus tag) via the strong cpcB560 promoter draws attention to the use of peptide tags to positively modulate expression of potentially toxic proteins.
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Affiliation(s)
- Jason Dexter
- College of Life Science and Technology, Beijing University of Chemical Technology, 15, Beisanhuan East Road, Chaoyang District, Beijing 100029, China; Cyanoworks, LLC, 1771 Haskell Rd., Olean, NY 14760, USA.
| | - Dariusz Dziga
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 31-007 Kraków, Poland.
| | - Jing Lv
- New Energy Research Center, China University of Petroleum (Beijing), 18 Fuxue Road, Changping District, Beijing 102249, China.
| | - Junqi Zhu
- College of Life Science and Technology, Beijing University of Chemical Technology, 15, Beisanhuan East Road, Chaoyang District, Beijing 100029, China.
| | - Wojciech Strzalka
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 31-007 Kraków, Poland.
| | - Anna Maksylewicz
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 31-007 Kraków, Poland.
| | - Magdalena Maroszek
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 31-007 Kraków, Poland.
| | - Sylwia Marek
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 31-007 Kraków, Poland.
| | - Pengcheng Fu
- College of Life Science and Technology, Beijing University of Chemical Technology, 15, Beisanhuan East Road, Chaoyang District, Beijing 100029, China.
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19
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Morón-López J, Nieto-Reyes L, El-Shehawy R. Assessment of the influence of key abiotic factors on the alternative microcystin degradation pathway(s) (mlr -): A detailed comparison with the mlr route (mlr +). THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 599-600:1945-1953. [PMID: 28549370 DOI: 10.1016/j.scitotenv.2017.04.042] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 04/06/2017] [Accepted: 04/06/2017] [Indexed: 06/07/2023]
Abstract
Cyanobacterial proliferation and toxin production in water bodies around the world have led to global concern about the control of these issues. Indigenous bacteria have been shown to degrade the cyanotoxin microcystin (MC) in natural environments. The mlr cluster has been widely used as a marker for microcystin biodegradation; however, recent studies have shown that alternative pathway(s) also contribute to the natural removal of MCs in the ecosystem. The main objective of this study is to provide initial insights concerning how key abiotic factors affect the rate of MC biodegradation via alternative pathway(s) and to provide a detailed comparison with the mlr+ pathway. Our results show that nutrient inputs and previous exposure to MCs trigger changes in the rate of MC degradation via alternative pathway(s), while temperature does not produce any significant change. Our results further indicate that the alternative pathway(s) may be less efficient at degrading MCs than the mlr+ pathway, suggesting the importance of microbial diversity in determining the half-life of MCs in the water column.
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20
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A Novel and Native Microcystin-Degrading Bacterium of Sphingopyxis sp. Isolated from Lake Taihu. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14101187. [PMID: 28984840 PMCID: PMC5664688 DOI: 10.3390/ijerph14101187] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 09/28/2017] [Accepted: 09/30/2017] [Indexed: 11/22/2022]
Abstract
A native, highly efficient microcystin-LR (MC-LR)-degrading bacterium named a7 was isolated from Lake Taihu and identified as Sphingopyxis sp. by 16S rDNA sequence analysis. The strain a7 could totally degrade MC-LR at a rate of 3.33 mg/(L·h), as detected by high-performance liquid chromatography (HPLC). The mlrA, mlrC, and mlrD genes were detected in the strain a7 by sequence analysis. Tetrapeptide and Adda—which are the middle metabolites of MC-LR—were analyzed via liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) during degradation. These metabolites were degraded completely, which suggested that the native Sphingopyxis sp. a7 was highly efficient in MC-LR degradation under bench conditions. Thus, strain a7 exhibited a significant potential application for bioremediation in water bodies contaminated by MC-LR produced by harmful cyanobacterial blooms.
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21
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Wang R, Li J, Jiang Y, Lu Z, Li R, Li J. Heterologous expression of mlrA gene originated from Novosphingobium sp. THN1 to degrade microcystin-RR and identify the first step involved in degradation pathway. CHEMOSPHERE 2017; 184:159-167. [PMID: 28586656 DOI: 10.1016/j.chemosphere.2017.05.086] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 05/03/2017] [Accepted: 05/13/2017] [Indexed: 06/07/2023]
Abstract
Information on the catalytic role of mlrA gene-encoded enzyme (MlrA) in microcystin-RR (MC-RR) biodegradation was limited. This study succeeded in expressing mlrA homolog of Novosphingobium sp. THN1 in heterologous host for the first time, by constructing a recombinant bacterium. Mass spectrometric analysis showed that the recombinant MlrA hydrolyzed MC-RR into linear intermediate product by cleaving the peptide bond between Adda and arginine residue, greatly detoxifying MC-RR. This finding clearly manifested that the MlrA homolog of THN1 strain possesses its original catalytic function, and ring-opening constituted the first step in MC-RR biodegradation pathway of THN1 strain. Moreover, MC-RR degradation by intact recombinant cells and cell-free crude enzyme (CE) from recombinant was compared. Results exhibited that intact recombinant was able to degrade 20 μg mL-1 MC-RR more quickly than CE, with the maximum rate of 9.22 μg mL-1 h-1 in the first 8 h. Thus, this study provided new insights on the catalytic activity and roles of MlrA originated from THN1 strain in MC-RR biodegradation process, which lay a foundation for efficiently removing and detoxifying MC-RR, and exploring downstream steps in MC-RR biodegradation pathway of THN1 strain.
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Affiliation(s)
- Ruiping Wang
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
| | - Jieming Li
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
| | - Yongguang Jiang
- Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Sciences, Shenzhen University, Shenzhen, Guangdong 518060, China
| | - Zhijiang Lu
- Department of Irrigation and Drainage, China Institute of Water Resources and Hydropower Research, Beijing 100048, China
| | - Renhui Li
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Ji Li
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
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22
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Li J, Li R, Li J. Current research scenario for microcystins biodegradation - A review on fundamental knowledge, application prospects and challenges. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 595:615-632. [PMID: 28407581 DOI: 10.1016/j.scitotenv.2017.03.285] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 03/26/2017] [Accepted: 03/31/2017] [Indexed: 05/20/2023]
Abstract
Microcystins (MCs) are common cyanotoxins produced by harmful cyanobacterial blooms (HCBs) and severely threaten human and ecosystems health. Biodegradation is an efficient and sustainable biological strategy for MCs removal. Many novel findings in fundamental knowledge and application potential of MC-biodegradation have been documented. Little effort has devoted to summarize and comment recent research progress on MC-biodegradation, and discuss the research problems and gaps. This review deals with current research scenario in aerobic and anaerobic biodegradation for MCs. Diverse organisms capable of degrading MCs are encapsulated. Enzymatic mechanisms and influence factors regulating aerobic and anaerobic MC-biodegradation are summarized and discussed, which are essential for assessing and reducing MC-risks during HCBs episodes. Also, we propose some ideas to solve the challenges and bottleneck problems in practical application of MC-biodegradation, and discuss research gaps and promising research methods which deserve special attention. This review may provide new insights on future direction of MC-biodegradation research, in order to further broaden its application prospects for bioremediation.
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Affiliation(s)
- Jieming Li
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
| | - Renhui Li
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Ji Li
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
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23
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D'Anglada LV. Editorial on the special issue “harmful algal blooms (HABs) and public health: progress and current challenges”. Toxins (Basel) 2016; 7:4437-41. [PMID: 26837093 PMCID: PMC4663512 DOI: 10.3390/toxins7114437] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Lesley V D'Anglada
- U.S. Environmental Protection Agency, Office of Science and Technology, Office of Water, 1200 Pennsylvania Ave., N.W., Washington, DC 20460, USA.
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