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Sahabudin E, Kubo S, Yuzir MAM, Othman N, Nadia Md Akhir F, Suzuki K, Yoneda K, Maeda Y, Suzuki I, Hara H, Iwamoto K. The cadmium tolerance and bioaccumulation mechanism of Tetratostichococcus sp. P1: insight from transcriptomics analysis. Bioengineered 2024; 15:2314888. [PMID: 38375815 PMCID: PMC11633185 DOI: 10.1080/21655979.2024.2314888] [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: 12/16/2023] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 02/21/2024] Open
Abstract
Cadmium (Cd) has become a severe issue in relatively low concentration and attracts expert attention due to its toxicity, accumulation, and biomagnification in living organisms. Cd does not have a biological role and causes serious health issues. Therefore, Cd pollutants should be reduced and removed from the environment. Microalgae have great potential for Cd absorption for waste treatment since they are more environmentally friendly than existing treatment methods and have strong metal sorption selectivity. This study evaluated the tolerance and ability of the microalga Tetratostichococcus sp. P1 to remove Cd ions under acidic conditions and reveal mechanisms based on transcriptomics analysis. The results showed that Tetratostichococcus sp. P1 had a high Cd tolerance that survived under the presence of Cd up to 100 µM, and IC50, the half-maximal inhibitory concentration value, was 57.0 μM, calculated from the change in growth rate based on the chlorophyll content. Long-term Cd exposure affected the algal morphology and photosynthetic pigments of the alga. Tetratostichococcus sp. P1 removed Cd with a maximum uptake of 1.55 mg g-1 dry weight. Transcriptomic analysis revealed the upregulation of the expression of genes related to metal binding, such as metallothionein. Group A, Group B transporters and glutathione, were also found upregulated. While the downregulation of the genes were related to photosynthesis, mitochondria electron transport, ABC-2 transporter, polysaccharide metabolic process, and cell division. This research is the first study on heavy metal bioremediation using Tetratostichococcus sp. P1 and provides a new potential microalga strain for heavy metal removal in wastewater.[Figure: see text]Abbreviations:BP: Biological process; bZIP: Basic Leucine Zipper; CC: Cellular component; ccc1: Ca (II)-sensitive cross complementary 1; Cd: Cadmium; CDF: Cation diffusion facilitator; Chl: Chlorophyll; CTR: Cu TRansporter families; DAGs: Directed acyclic graphs; DEGs: Differentially expressed genes; DVR: Divinyl chlorophyllide, an 8-vinyl-reductase; FPN: FerroportinN; FTIR: Fourier transform infrared; FTR: Fe TRansporter; GO: Gene Ontology; IC50: Growth half maximal inhibitory concentration; ICP: Inductively coupled plasma; MF: molecular function; NRAMPs: Natural resistance-associated aacrophage proteins; OD: Optical density; RPKM: Reads Per Kilobase of Exon Per Million Reads Mapped; VIT1: Vacuolar iron transporter 1 families; ZIPs: Zrt-, Irt-like proteins.
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Affiliation(s)
- Eri Sahabudin
- Department of Chemical and Environmental Engineering, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Kuala Lumpur, Malaysia
| | - Shohei Kubo
- Graduate School of Science and Technology, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Muhamad Ali Muhammad Yuzir
- Department of Chemical and Environmental Engineering, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Kuala Lumpur, Malaysia
| | - Nor’azizi Othman
- Department of Chemical and Environmental Engineering, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Kuala Lumpur, Malaysia
| | - Fazrena Nadia Md Akhir
- Department of Chemical and Environmental Engineering, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Kuala Lumpur, Malaysia
| | - Kengo Suzuki
- Department of Chemical and Environmental Engineering, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Kuala Lumpur, Malaysia
- Euglena Co. Ltd, Minato‑ku, Japan
- Microalgae Production Control Technology Laboratory, Yokohama, Kanagawa, Japan
| | - Kohei Yoneda
- Institute of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yoshiaki Maeda
- Institute of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Iwane Suzuki
- Institute of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Hirofumi Hara
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Japan
| | - Koji Iwamoto
- Department of Chemical and Environmental Engineering, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Kuala Lumpur, Malaysia
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Lu X, Qiu S, Li Z, Ge S. Pathways, challenges, and strategies for enhancing anaerobic production of short-chain and medium-chain carboxylic acids from algal slurry derived from wastewater. BIORESOURCE TECHNOLOGY 2024; 413:131528. [PMID: 39321935 DOI: 10.1016/j.biortech.2024.131528] [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: 04/12/2024] [Revised: 08/28/2024] [Accepted: 09/22/2024] [Indexed: 09/27/2024]
Abstract
Algal slurry (AS) generated from microalgae-based wastewater treatment processes holds significant potential for carboxylic acids production through anaerobic digestion (AD), which have emerged as promising products due to their high energy density, great economic value, and versatile applications. A comprehensive analysis of the pathways and optimization strategies for producing short-chain (SCCAs) and medium-chain (MCCAs) carboxylic acids using AS substrates is presented in this review. It begins by introducing and comparing two types of microalgae-based wastewater treatment processes: the microalgae process and the microalgal-bacterial consortia process. Afterwards, the review systematically examines the metabolic pathways involved in SCCAs and MCCAs production using AS substrates. Moreover, pretreatment strategies for enhancing the release of organic matter are critically discussed. Ultimately, specific emphasis is placed on addressing technical challenges and discussing future perspectives. This review provides a deeper understanding of the mechanisms and strategies involved in carboxylic acids production from wastewater-generated AS.
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Affiliation(s)
- Xiyang Lu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China
| | - Shuang Qiu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China
| | - Zimu Li
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China
| | - Shijian Ge
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China.
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Pathom-Aree W, Sattayawat P, Inwongwan S, Cheirsilp B, Liewtrakula N, Maneechote W, Rangseekaew P, Ahmad F, Mehmood MA, Gao F, Srinuanpan S. Microalgae growth-promoting bacteria for cultivation strategies: Recent updates and progress. Microbiol Res 2024; 286:127813. [PMID: 38917638 DOI: 10.1016/j.micres.2024.127813] [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: 04/10/2024] [Revised: 06/02/2024] [Accepted: 06/17/2024] [Indexed: 06/27/2024]
Abstract
Microalgae growth-promoting bacteria (MGPB), both actinobacteria and non-actinobacteria, have received considerable attention recently because of their potential to develop microalgae-bacteria co-culture strategies for improved efficiency and sustainability of the water-energy-environment nexus. Owing to their diverse metabolic pathways and ability to adapt to diverse conditions, microalgal-MGPB co-cultures could be promising biological systems under uncertain environmental and nutrient conditions. This review proposes the recent updates and progress on MGPB for microalgae cultivation through co-culture strategies. Firstly, potential MGPB strains for microalgae cultivation are introduced. Following, microalgal-MGPB interaction mechanisms and applications of their co-cultures for biomass production and wastewater treatment are reviewed. Moreover, state-of-the-art studies on synthetic biology and metabolic network analysis, along with the challenges and prospects of opting these approaches for microalgal-MGPB co-cultures are presented. It is anticipated that these strategies may significantly improve the sustainability of microalgal-MGPB co-cultures for wastewater treatment, biomass valorization, and bioproducts synthesis in a circular bioeconomy paradigm.
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Affiliation(s)
- Wasu Pathom-Aree
- Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Excellence in Microbial Diversity and Sustainable Utilization, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Pachara Sattayawat
- Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Excellence in Microbial Diversity and Sustainable Utilization, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Sahutchai Inwongwan
- Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Excellence in Microbial Diversity and Sustainable Utilization, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Benjamas Cheirsilp
- Program of Biotechnology, Center of Excellence in Innovative Biotechnology for Sustainable Utilization of Bioresources, Faculty of Agro-Industry, Prince of Songkla University, Songkhla 90110, Thailand
| | - Naruepon Liewtrakula
- Program of Biotechnology, Center of Excellence in Innovative Biotechnology for Sustainable Utilization of Bioresources, Faculty of Agro-Industry, Prince of Songkla University, Songkhla 90110, Thailand
| | - Wageeporn Maneechote
- Program of Biotechnology, Center of Excellence in Innovative Biotechnology for Sustainable Utilization of Bioresources, Faculty of Agro-Industry, Prince of Songkla University, Songkhla 90110, Thailand; Office of Research Administration, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Pharada Rangseekaew
- Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Excellence in Microbial Diversity and Sustainable Utilization, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Fiaz Ahmad
- Key Laboratory for Space Bioscience & Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, China
| | - Muhammad Aamer Mehmood
- Bioenergy Research Center, Department of Bioinformatics & Biotechnology, Government College University Faisalabad, Faisalabad 38000, Pakistan
| | - Fengzheng Gao
- Sustainable Food Processing Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, Zurich 8092, Switzerland; Laboratory of Nutrition and Metabolic Epigenetics, Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach 8603, Switzerland
| | - Sirasit Srinuanpan
- Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Excellence in Microbial Diversity and Sustainable Utilization, Chiang Mai University, Chiang Mai 50200, Thailand; Office of Research Administration, Chiang Mai University, Chiang Mai 50200, Thailand; Biorefinery and Bioprocess Engineering Research Cluster, Chiang Mai University, Chiang Mai 50200, Thailand.
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Ferrari M, Marieschi M, Cozza R, Torelli A. Phytochelatin Synthase: An In Silico Comparative Analysis in Cyanobacteria and Eukaryotic Microalgae. PLANTS (BASEL, SWITZERLAND) 2024; 13:2165. [PMID: 39124283 PMCID: PMC11314372 DOI: 10.3390/plants13152165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Revised: 07/09/2024] [Accepted: 08/01/2024] [Indexed: 08/12/2024]
Abstract
Phytochelatins (PCs) are small cysteine-rich peptides involved in metal detoxification, not genetically encoded but enzymatically synthesized by phytochelatin synthases (PCSs) starting from glutathione. The constitutive PCS expression even in the absence of metal contamination, the wide phylogenetic distribution and the similarity between PCSs and the papain-type cysteine protease catalytic domain suggest a wide range of functions for PCSs. These proteins, widely studied in land plants, have not been fully analyzed in algae and cyanobacteria, although these organisms are the first to cope with heavy-metal stress in aquatic environments and can be exploited for phytoremediation. To fill this gap, we compared the features of the PCS proteins of different cyanobacterial and algal taxa by phylogenetic linkage. The analyzed sequences fall into two main, already known groups of PCS-like proteins. Contrary to previous assumptions, they are not classed as prokaryotic and eukaryotic sequences, but rather as sequences characterized by the alternative presence of asparagine and aspartic/glutamic acid residues in proximity of the catalytic cysteine. The presence of these enzymes with peculiar features suggests differences in their post-translational regulation related to cell/environmental requirements or different cell functions rather than to differences due to their belonging to different phylogenetic taxa.
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Affiliation(s)
- Michele Ferrari
- Department of Biology, Ecology and Earth Science, University of Calabria, Arcavacata di Rende, 87036 Cosenza, Italy; (M.F.); (R.C.)
| | - Matteo Marieschi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Viale delle Scienze 11/A, 43124 Parma, Italy;
| | - Radiana Cozza
- Department of Biology, Ecology and Earth Science, University of Calabria, Arcavacata di Rende, 87036 Cosenza, Italy; (M.F.); (R.C.)
| | - Anna Torelli
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Viale delle Scienze 11/A, 43124 Parma, Italy;
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Chen D, Wang G, Chen C, Feng Z, Jiang Y, Yu H, Li M, Chao Y, Tang Y, Wang S, Qiu R. The interplay between microalgae and toxic metal(loid)s: mechanisms and implications in AMD phycoremediation coupled with Fe/Mn mineralization. JOURNAL OF HAZARDOUS MATERIALS 2023; 454:131498. [PMID: 37146335 DOI: 10.1016/j.jhazmat.2023.131498] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 04/10/2023] [Accepted: 04/24/2023] [Indexed: 05/07/2023]
Abstract
Acid mine drainage (AMD) is low-pH with high concentration of sulfates and toxic metal(loid)s (e.g. As, Cd, Pb, Cu, Zn), thereby posing a global environmental problem. For decades, microalgae have been used to remediate metal(loid)s in AMD, as they have various adaptive mechanisms for tolerating extreme environmental stress. Their main phycoremediation mechanisms are biosorption, bioaccumulation, coupling with sulfate-reducing bacteria, alkalization, biotransformation, and Fe/Mn mineral formation. This review summarizes how microalgae cope with metal(loid) stress and their specific mechanisms of phycoremediation in AMD. Based on the universal physiological characteristics of microalgae and the properties of their secretions, several Fe/Mn mineralization mechanisms induced by photosynthesis, free radicals, microalgal-bacterial reciprocity, and algal organic matter are proposed. Notably, microalgae can also reduce Fe(III) and inhibit mineralization, which is environmentally unfavorable. Therefore, the comprehensive environmental effects of microalgal co-occurring and cyclical opposing processes must be carefully considered. Using chemical and biological perspectives, this review innovatively proposes several specific processes and mechanisms of Fe/Mn mineralization that are mediated by microalgae, providing a theoretical basis for the geochemistry of metal(loid)s and natural attenuation of pollutants in AMD.
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Affiliation(s)
- Daijie Chen
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China
| | - Guobao Wang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China; Guangdong Provincial Key Laboratory for Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510006, China
| | - Chiyu Chen
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China
| | - Zekai Feng
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China
| | - Yuanyuan Jiang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China
| | - Hang Yu
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China
| | - Mengyao Li
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China
| | - Yuanqing Chao
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China; Guangdong Provincial Key Laboratory for Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510006, China
| | - Yetao Tang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China; Guangdong Provincial Key Laboratory for Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510006, China
| | - Shizhong Wang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China; Guangdong Provincial Key Laboratory for Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510006, China.
| | - Rongliang Qiu
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Agricultural & Rural Pollution Abatement and Environmental Safety, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
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6
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Seregin IV, Kozhevnikova AD. Phytochelatins: Sulfur-Containing Metal(loid)-Chelating Ligands in Plants. Int J Mol Sci 2023; 24:2430. [PMID: 36768751 PMCID: PMC9917255 DOI: 10.3390/ijms24032430] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 01/28/2023] Open
Abstract
Phytochelatins (PCs) are small cysteine-rich peptides capable of binding metal(loid)s via SH-groups. Although the biosynthesis of PCs can be induced in vivo by various metal(loid)s, PCs are mainly involved in the detoxification of cadmium and arsenic (III), as well as mercury, zinc, lead, and copper ions, which have high affinities for S-containing ligands. The present review provides a comprehensive account of the recent data on PC biosynthesis, structure, and role in metal(loid) transport and sequestration in the vacuoles of plant cells. A comparative analysis of PC accumulation in hyperaccumulator plants, which accumulate metal(loid)s in their shoots, and in the excluders, which accumulate metal(loid)s in their roots, investigates the question of whether the endogenous PC concentration determines a plant's tolerance to metal(loid)s. Summarizing the available data, it can be concluded that PCs are not involved in metal(loid) hyperaccumulation machinery, though they play a key role in metal(loid) homeostasis. Unraveling the physiological role of metal(loid)-binding ligands is a fundamental problem of modern molecular biology, plant physiology, ionomics, and toxicology, and is important for the development of technologies used in phytoremediation, biofortification, and phytomining.
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Affiliation(s)
- Ilya V. Seregin
- K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya St., 35, 127276 Moscow, Russia
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Synergy between microalgae and microbiome in polluted waters. Trends Microbiol 2023; 31:9-21. [PMID: 35985939 DOI: 10.1016/j.tim.2022.06.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 06/24/2022] [Accepted: 06/27/2022] [Indexed: 11/22/2022]
Abstract
Microalga-microbiome interactions are central to both health and disease of aquatic environments. Despite impressive advances in deciphering how microorganisms participate in and impact aquatic ecosystems, the evolution and ecological involvement of microalgae and the microbiome in polluted waters are typically studied independently. Here, the phycosphere (i.e., the consortia of microalgae and the related microbiome) is regarded as an independent and integrated life form, and we summarize the survival strategies exhibited by this symbiont when exposed to anthropogenic pollution. We highlight the cellular strategies and discuss the modulation at the transcriptional and population levels, which reciprocally alters community structure or genome composition for medium-term acclimation or long-term adaptation. We propose a 'PollutantBiome' concept to help the understanding of microalga-microbiome interactions and development of beneficial microbial synthetic communities for pollutant remediation.
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Abbew AW, Amadu AA, Qiu S, Champagne P, Adebayo I, Anifowose PO, Ge S. Understanding the influence of free nitrous acid on microalgal-bacterial consortium in wastewater treatment: A critical review. BIORESOURCE TECHNOLOGY 2022; 363:127916. [PMID: 36087656 DOI: 10.1016/j.biortech.2022.127916] [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: 07/12/2022] [Revised: 08/31/2022] [Accepted: 09/04/2022] [Indexed: 06/15/2023]
Abstract
Microalgal-bacterial consortium (MBC) constitutes a sustainable and efficient alternative to the conventional activated sludge process for wastewater treatment (WWT). Recently, integrating the MBC process with nitritation (i.e., shortcut MBC) has been proposed to achieve added benefits of reduced carbon and aeration requirements. In the shortcut MBC system, nitrite or free nitrous acid (FNA) accumulation exerts antimicrobial influences that disrupt the stable process performance. In this review, the formation and interactions that influence the performance of the MBC were firstly summarized. Then the influence of FNA on microalgal and bacterial monocultures and related mechanisms together with the knowledge gaps of FNA influence on the shortcut MBC were highlighted. Other challenges and future perspectives that impact the scale-up of the shortcut MBC for WWT were illustrated. A potential roadmap is proposed on how to maximize the stable operation of the shortcut MBC system for sustainable WWT and high-value biomass production.
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Affiliation(s)
- Abdul-Wahab Abbew
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China
| | - Ayesha Algade Amadu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China
| | - Shuang Qiu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China
| | - Pascale Champagne
- Department of Chemistry, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Ismaeel Adebayo
- School of Chemical Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China
| | - Peter Oluwaseun Anifowose
- School of Science, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China
| | - Shijian Ge
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China.
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Díaz S, Aguilera Á, de Figueras CG, de Francisco P, Olsson S, Puente-Sánchez F, González-Pastor JE. Heterologous Expression of the Phytochelatin Synthase CaPCS2 from Chlamydomonas acidophila and Its Effect on Different Stress Factors in Escherichia coli. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19137692. [PMID: 35805349 PMCID: PMC9265389 DOI: 10.3390/ijerph19137692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/19/2022] [Accepted: 06/21/2022] [Indexed: 11/19/2022]
Abstract
Phytochelatins (PCs) are cysteine-rich small peptides, enzymatically synthesized from reduced glutathione (GSH) by cytosolic enzyme phytochelatin synthase (PCS). The open reading frame (ORF) of the phytochelatin synthase CaPCS2 gene from the microalgae Chlamydomonas acidophila was heterologously expressed in Escherichia coli strain DH5α, to analyze its role in protection against various abiotic agents that cause cellular stress. The transformed E. coli strain showed increased tolerance to exposure to different heavy metals (HMs) and arsenic (As), as well as to acidic pH and exposure to UVB, salt, or perchlorate. In addition to metal detoxification activity, new functions have also been reported for PCS and PCs. According to the results obtained in this work, the heterologous expression of CaPCS2 in E. coli provides protection against oxidative stress produced by metals and exposure to different ROS-inducing agents. However, the function of this PCS is not related to HM bioaccumulation.
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Affiliation(s)
- Silvia Díaz
- Department of Genetics, Physiology and Microbiology, Faculty of Biology, C. José Antonio Novais, 12, Universidad Complutense de Madrid (UCM), 28040 Madrid, Spain
- Correspondence:
| | - Ángeles Aguilera
- Department of Molecular Biology, Centro de Astrobiología (CSIC-INTA), Carretera de Ajalvir, km 4, Torrejón de Ardoz, 28850 Madrid, Spain; (Á.A.); (C.G.d.F.); (P.d.F.); (J.E.G.-P.)
| | - Carolina G. de Figueras
- Department of Molecular Biology, Centro de Astrobiología (CSIC-INTA), Carretera de Ajalvir, km 4, Torrejón de Ardoz, 28850 Madrid, Spain; (Á.A.); (C.G.d.F.); (P.d.F.); (J.E.G.-P.)
| | - Patricia de Francisco
- Department of Molecular Biology, Centro de Astrobiología (CSIC-INTA), Carretera de Ajalvir, km 4, Torrejón de Ardoz, 28850 Madrid, Spain; (Á.A.); (C.G.d.F.); (P.d.F.); (J.E.G.-P.)
| | - Sanna Olsson
- Department of Forest Ecology and Genetics, Forest Research Centre (INIA, CSIC), Carretera de La Coruña, km 7.5, 28040 Madrid, Spain;
| | - Fernando Puente-Sánchez
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Lennart Hjelms väg 9, 756 51 Uppsala, Sweden;
| | - José Eduardo González-Pastor
- Department of Molecular Biology, Centro de Astrobiología (CSIC-INTA), Carretera de Ajalvir, km 4, Torrejón de Ardoz, 28850 Madrid, Spain; (Á.A.); (C.G.d.F.); (P.d.F.); (J.E.G.-P.)
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Iqbal K, Saxena A, Pande P, Tiwari A, Chandra Joshi N, Varma A, Mishra A. Microalgae-bacterial granular consortium: Striding towards sustainable production of biohydrogen coupled with wastewater treatment. BIORESOURCE TECHNOLOGY 2022; 354:127203. [PMID: 35462016 DOI: 10.1016/j.biortech.2022.127203] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/13/2022] [Accepted: 04/18/2022] [Indexed: 06/14/2023]
Abstract
Anthropogenic activities have drastically affected the environment, leading to increased waste accumulation in atmospheric bodies, including water. Wastewater treatment is an energy-consuming process and typically requires thousands of kilowatt hours of energy. This enormous energy demand can be fulfilled by utilizing the microbial electrolysis route to breakdown organic pollutants in wastewater which produces clean water and biohydrogen as a by-product of the reaction. Microalgae are the promising microorganism for the biohydrogen production, and it has been investigated that the interaction between microalgae and bacteria can be used to boost the yield of biohydrogen. Consortium of algae and bacteria resulting around 50-60% more biohydrogen production compared to the biohydrogen production of algae and bacteria separately. This review summarises the recent development in different microalgae-bacteria granular consortium systems successfully employed for biohydrogen generation. We also discuss the limitations in biohydrogen production and factors affecting its production from wastewater.
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Affiliation(s)
- Khushboo Iqbal
- Amity Institute of Microbial Technology, Amity University Uttar Pradesh, Noida 201301, India
| | - Abhishek Saxena
- Diatom Research Laboratory, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh 201301, India
| | - Priyanshi Pande
- Amity Institute of Microbial Technology, Amity University Uttar Pradesh, Noida 201301, India
| | - Archana Tiwari
- Diatom Research Laboratory, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh 201301, India
| | - Naveen Chandra Joshi
- Amity Institute of Microbial Technology, Amity University Uttar Pradesh, Noida 201301, India
| | - Ajit Varma
- Amity Institute of Microbial Technology, Amity University Uttar Pradesh, Noida 201301, India
| | - Arti Mishra
- Amity Institute of Microbial Technology, Amity University Uttar Pradesh, Noida 201301, India.
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11
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Manikandan A, Suresh Babu P, Shyamalagowri S, Kamaraj M, Muthukumaran P, Aravind J. Emerging role of microalgae in heavy metal bioremediation. J Basic Microbiol 2021; 62:330-347. [PMID: 34724223 DOI: 10.1002/jobm.202100363] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/27/2021] [Accepted: 10/17/2021] [Indexed: 12/16/2022]
Abstract
Microalgae have been publicized for their diversified dominance responsiveness and bioaccumulation potential toward pollutants in an ecosystem. Also, algal's incredible capability as biocatalysts in environmental appliances has been well elucidated owing to their robustness and simple nutritional demand. Additionally, microalgae can deliver various collections of bio-based chemical compounds helpful for diversified applications, especially as green alternatives. The environment has been contaminated with various polluting agents; one principal polluting agent is heavy metals which are carcinogenic and show toxicity even in minimal quantity, cause unsatisfactory threats to the environmental ecosystem, including human and animal health. There is a prominent tendency to apply microalgae in the phytoremediation of heavy metals compounds because of its vast benefits, including great accessibility, cost-effective, excellent toxic metal eliminating efficiency, and nontoxic to the ecosystem. This review uncovers the most recent advancements and mechanisms associated with the bioremediation process and biosorption interaction of substantial harmful synthetic compounds processing microalgae species. Furthermore, future challenges and prospects in the utilization of microalgae in heavy metals bioremediation are also explored. The current review aims to give valuable information to aid the advancement of robust and proficient future microalgae-based heavy metal bioremediation innovations and summarizing a wide range of benefits socioeconomic scope to be employed in heavy metal compound removal in environment system.
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Affiliation(s)
- Arumugam Manikandan
- Industrial Biotechnology, Bharath Institute of Higher Education and Research, Chennai, Tamil Nadu, India
| | - Palanisamy Suresh Babu
- Department of Biotechnology, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences (SIMATS), Thandalam, Chennai, Tamil Nadu, India.,Faculty of Pharmaceutical Sciences, UCSI University, Cheras, Kuala Lumpur, Malaysia
| | | | - Murugesan Kamaraj
- Department of Biotechnology, College of Biological and Chemical Engineering, Addis Ababa Science and Technology University, Addis Ababa, Ethiopia
| | - Peraman Muthukumaran
- Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, India
| | - Jeyaseelan Aravind
- Department of Civil Engineering, Environmental Research, Dhirajlal Gandhi College of Technology, Kamalapuram Sikkanampatty, Omalur, Salem, India
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12
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Tripathi S, Poluri KM. Heavy metal detoxification mechanisms by microalgae: Insights from transcriptomics analysis. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 285:117443. [PMID: 34090077 DOI: 10.1016/j.envpol.2021.117443] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/07/2021] [Accepted: 05/20/2021] [Indexed: 05/20/2023]
Abstract
Heavy metal pollution in ecosystem is a global threat. The associated toxicity and carcinogenic nature of heavy metals/metalloids such as mercury, cadmium, lead, and arsenic are imposing a severe risk to both ecological diversity and human lives. Harnessing the adaptive feature of microalgae for remediating toxic heavy metal has reached a milestone in past few decades. Transcriptomics analyses have provided mechanistic insights to map the dynamics of cellular events under heavy metal stress, thus deciphering the strategic responses of microalgae. Here, the present review comprehensively addresses the elicited molecular responses of microalgae to detoxify the heavy metal stress. The review highlights the intricate role of biochemical components and signaling networks mediating stress responsive transitions of microalgae at physiological level. Furthermore, the differential gene expression signifying the transporters involved in uptake, distribution/sequestration, and efflux of heavy metal has also been reviewed. In a nutshell, this study provided a comprehensive understanding of the molecular mechanisms adopted by microalgae at transcriptome level to nullify the oxidative stress while detoxifying the heavy metals.
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Affiliation(s)
- Shweta Tripathi
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, Uttarakhand, India
| | - Krishna Mohan Poluri
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, Uttarakhand, India; Centre for Transportation Systems, Indian Institute of Technology Roorkee, Roorkee, 247667, Uttarakhand, India.
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13
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You X, Xu N, Yang X, Sun W. Pollutants affect algae-bacteria interactions: A critical review. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 276:116723. [PMID: 33611207 DOI: 10.1016/j.envpol.2021.116723] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 02/05/2021] [Accepted: 02/08/2021] [Indexed: 06/12/2023]
Abstract
With increasing concerns on the ecological risks of pollutants, many efforts have been devoted to revealing the toxic effects of pollutants on algae or bacteria in their monocultures. However, how pollutants affect algae and bacteria in their cocultures is still elusive but crucial due to its more environmental relevance. The present review outlines the interactions between algae and bacteria, reveals the influential mechanisms of pollutants (including pesticides, metals, engineered nanomaterials, pharmaceutical and personal care products, and aromatic pollutants) to algae and bacteria in their coexisted systems, and puts forward prospects for further advancing toxic studies in algal-bacterial systems. Pollutants affect the physiological and ecological functions of bacteria and algae by interfering with their relationships. Cell-to-cell adhesion, substrate exchange and biodegradation of organic pollutants, enhancement of signal transduction, and horizontal transfer of tolerance genes are important defense strategies in algal-bacterial systems to cope with pollution stress. Developing suitable algal-bacterial models, identifying cross-kingdom signaling molecules, and deciphering the horizontal transfer of pollutant resistant genes between algae and bacteria under pollution stress are the way forward to fully exploit the risks of pollutants in natural aquatic environments.
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Affiliation(s)
- Xiuqi You
- College of Environmental Sciences and Engineering, Peking University, State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, International Joint Laboratory for Regional Pollution Control, Ministry of Education, Beijing, 100871, China
| | - Nan Xu
- Shenzhen Key Laboratory for Heavy Metal Pollution Control and Reutilization, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Xi Yang
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, 810016, China
| | - Weiling Sun
- College of Environmental Sciences and Engineering, Peking University, State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, International Joint Laboratory for Regional Pollution Control, Ministry of Education, Beijing, 100871, China.
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14
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Chen R, Huangfu L, Lu Y, Fang H, Xu Y, Li P, Zhou Y, Xu C, Huang J, Yang Z. Adaptive innovation of green plants by horizontal gene transfer. Biotechnol Adv 2020; 46:107671. [PMID: 33242576 DOI: 10.1016/j.biotechadv.2020.107671] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 11/18/2020] [Accepted: 11/20/2020] [Indexed: 12/16/2022]
Abstract
Horizontal gene transfer (HGT) refers to the movement of genetic material between distinct species by means other than sexual reproduction. HGT has contributed tremendously to the genome plasticity and adaptive evolution of prokaryotes and certain unicellular eukaryotes. The evolution of green plants from chlorophyte algae to angiosperms and from water to land represents a process of adaptation to diverse environments, which has been facilitated by acquisition of genetic material from other organisms. In this article, we review the occurrence of HGT in major lineages of green plants, including chlorophyte and charophyte green algae, bryophytes, lycophytes, ferns, and seed plants. In addition, we discuss the significance of horizontally acquired genes in the adaptive innovations of green plants and their potential applications to crop breeding and improvement.
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Affiliation(s)
- Rujia Chen
- Jiangsu Key Laboratory of Crop Genetics and Physiology, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Agricultural College of Yangzhou University, Yangzhou 225009, China; Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China
| | - Liexiang Huangfu
- Jiangsu Key Laboratory of Crop Genetics and Physiology, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Agricultural College of Yangzhou University, Yangzhou 225009, China; Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China
| | - Yue Lu
- Jiangsu Key Laboratory of Crop Genetics and Physiology, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Agricultural College of Yangzhou University, Yangzhou 225009, China; Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China
| | - Huimin Fang
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China
| | - Yang Xu
- Jiangsu Key Laboratory of Crop Genetics and Physiology, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Agricultural College of Yangzhou University, Yangzhou 225009, China; Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China
| | - Pengcheng Li
- Jiangsu Key Laboratory of Crop Genetics and Physiology, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Agricultural College of Yangzhou University, Yangzhou 225009, China; Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China
| | - Yong Zhou
- Jiangsu Key Laboratory of Crop Genetics and Physiology, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Agricultural College of Yangzhou University, Yangzhou 225009, China; Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China
| | - Chenwu Xu
- Jiangsu Key Laboratory of Crop Genetics and Physiology, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Agricultural College of Yangzhou University, Yangzhou 225009, China; Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China.
| | - Jinling Huang
- Department of Biology, East Carolina University, Greenville, NC 28590, USA; State Key Laboratory of Crop Stress Adaptation and Improvement, Key Laboratory of Plant Stress Biology, School of Life Sciences, Henan University, Kaifeng 475004, China; Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China.
| | - Zefeng Yang
- Jiangsu Key Laboratory of Crop Genetics and Physiology, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Agricultural College of Yangzhou University, Yangzhou 225009, China; Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China.
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15
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Lund PA, De Biase D, Liran O, Scheler O, Mira NP, Cetecioglu Z, Fernández EN, Bover-Cid S, Hall R, Sauer M, O'Byrne C. Understanding How Microorganisms Respond to Acid pH Is Central to Their Control and Successful Exploitation. Front Microbiol 2020; 11:556140. [PMID: 33117305 PMCID: PMC7553086 DOI: 10.3389/fmicb.2020.556140] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 08/21/2020] [Indexed: 12/20/2022] Open
Abstract
Microbes from the three domains of life, Bacteria, Archaea, and Eukarya, share the need to sense and respond to changes in the external and internal concentrations of protons. When the proton concentration is high, acidic conditions prevail and cells must respond appropriately to ensure that macromolecules and metabolic processes are sufficiently protected to sustain life. While, we have learned much in recent decades about the mechanisms that microbes use to cope with acid, including the unique challenges presented by organic acids, there is still much to be gained from developing a deeper understanding of the effects and responses to acid in microbes. In this perspective article, we survey the key molecular mechanisms known to be important for microbial survival during acid stress and discuss how this knowledge might be relevant to microbe-based applications and processes that are consequential for humans. We discuss the research approaches that have been taken to investigate the problem and highlight promising new avenues. We discuss the influence of acid on pathogens during the course of infections and highlight the potential of using organic acids in treatments for some types of infection. We explore the influence of acid stress on photosynthetic microbes, and on biotechnological and industrial processes, including those needed to produce organic acids. We highlight the importance of understanding acid stress in controlling spoilage and pathogenic microbes in the food chain. Finally, we invite colleagues with an interest in microbial responses to low pH to participate in the EU-funded COST Action network called EuroMicropH and contribute to a comprehensive database of literature on this topic that we are making publicly available.
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Affiliation(s)
- Peter A Lund
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Daniela De Biase
- Department of Medico-Surgical Sciences and Biotechnologies, Laboratory affiliated to the Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Sapienza University of Rome, Latina, Italy
| | - Oded Liran
- Department of Plant Sciences, MIGAL - Galilee Research Institute, Kiryat-Shemona, Israel
| | - Ott Scheler
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Nuno Pereira Mira
- Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Zeynep Cetecioglu
- Department of Chemical Engineering, KTH Royal Institute of Technology, Stockholm, Sweden
| | | | - Sara Bover-Cid
- IRTA, Food Safety Programme, Finca Camps i Armet, Monells, Spain
| | - Rebecca Hall
- School of Biosciences, Kent Fungal Group, University of Kent, Canterbury, United Kingdom
| | - Michael Sauer
- Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Conor O'Byrne
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, NUI Galway, Galway, Ireland
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16
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Eukaryotic and Prokaryotic Phytochelatin Synthases Differ Less in Functional Terms Than Previously Thought: A Comparative Analysis of Marchantia polymorpha and Geitlerinema sp. PCC 7407. PLANTS 2020; 9:plants9070914. [PMID: 32698350 PMCID: PMC7411734 DOI: 10.3390/plants9070914] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/12/2020] [Accepted: 07/16/2020] [Indexed: 12/12/2022]
Abstract
This paper reports functional studies on the enzyme phytochelatin synthase in the liverwort Marchantia polymorpha and the cyanobacterium Geitlerinema sp. strain PCC 7407. In vitro activity assays in control samples (cadmium-untreated) showed that phytochelatin synthase was constitutively expressed in both organisms. In the presence of 100 µM cadmium, in both the liverwort and the cyanobacterium, the enzyme was promptly activated in vitro, and produced phytochelatins up to the oligomer PC4. Likewise, in vivo exposure to 10–36 µM cadmium for 6-120 h induced in both organisms phytochelatin synthesis up to PC4. Furthermore, the glutathione (GSH) levels in M. polymorpha were constitutively low (compared with the average content in higher plants), but increased considerably under cadmium stress. Conversely, the GSH levels in Geitlerinema sp. PCC 7407 were constitutively high, but were halved under metal treatments. At odds with former papers, our results demonstrate that, as in M. polymorpha and other plants, the cyanobacterial phytochelatin synthase exposed to cadmium possesses manifest transpeptidasic activity, being able to synthesize phytochelatins with a degree of oligomerization higher than PC2. Therefore, prokaryotic and eukaryotic phytochelatin synthases differ less in functional terms than previously thought.
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17
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Vosolsobě S, Skokan R, Petrášek J. The evolutionary origins of auxin transport: what we know and what we need to know. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:3287-3295. [PMID: 32246155 DOI: 10.1093/jxb/eraa169] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 04/02/2020] [Indexed: 05/24/2023]
Abstract
Auxin, represented by indole-3-acetic acid (IAA), has for a long time been studied mainly with respect to the development of land plants, and recent evidence confirms that canonical nuclear auxin signaling is a land plant apomorphy. Increasing sequential and physiological data show that the presence of auxin transport machinery pre-dates the emergence of canonical signaling. In this review, we summarize the present state of knowledge regarding the origins of auxin transport in the green lineage (Viridiplantae), integrating both data from wet lab experiments and sequence evidence on the presence of PIN-FORMED (PIN), PIN-LIKES (PILS), and AUXIN RESISTANT 1/LIKE-AUX1 (AUX1/LAX) homologs. We discuss a high divergence of auxin carrier homologs among algal lineages and emphasize the urgent need for the establishment of good molecular biology models from within the streptophyte green algae. We further postulate and discuss two hypotheses for the ancestral role of auxin in the green lineage. First, auxin was present as a by-product of cell metabolism and the evolution of its transport was stimulated by the need for IAA sequestration and cell detoxification. Second, auxin was primarily a signaling compound, possibly of bacterial origin, and its activity in the pre-plant green algae was a consequence of long-term co-existence with bacteria in shared ecological consortia.
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Affiliation(s)
- Stanislav Vosolsobě
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Czech Republic
- The Czech Academy of Sciences, Institute of Experimental Botany, Rozvojová, Czech Republic
| | - Roman Skokan
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Czech Republic
- The Czech Academy of Sciences, Institute of Experimental Botany, Rozvojová, Czech Republic
| | - Jan Petrášek
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Czech Republic
- The Czech Academy of Sciences, Institute of Experimental Botany, Rozvojová, Czech Republic
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18
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Balzano S, Sardo A, Blasio M, Chahine TB, Dell’Anno F, Sansone C, Brunet C. Microalgal Metallothioneins and Phytochelatins and Their Potential Use in Bioremediation. Front Microbiol 2020; 11:517. [PMID: 32431671 PMCID: PMC7216689 DOI: 10.3389/fmicb.2020.00517] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/10/2020] [Indexed: 01/02/2023] Open
Abstract
The persistence of heavy metals (HMs) in the environment causes adverse effects to all living organisms; HMs accumulate along the food chain affecting different levels of biological organizations, from cells to tissues. HMs enter cells through transporter proteins and can bind to enzymes and nucleic acids interfering with their functioning. Strategies used by microalgae to minimize HM toxicity include the biosynthesis of metal-binding peptides that chelate metal cations inhibiting their activity. Metal-binding peptides include genetically encoded metallothioneins (MTs) and enzymatically produced phytochelatins (PCs). A number of techniques, including genetic engineering, focus on increasing the biosynthesis of MTs and PCs in microalgae. The present review reports the current knowledge on microalgal MTs and PCs and describes the state of art of their use for HM bioremediation and other putative biotechnological applications, also emphasizing on techniques aimed at increasing the cellular concentrations of MTs and PCs. In spite of the broad metabolic and chemical diversity of microalgae that are currently receiving increasing attention by biotechnological research, knowledge on MTs and PCs from these organisms is still limited to date.
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Affiliation(s)
- Sergio Balzano
- Stazione Zoologica Anton Dohrn Napoli (SZN), Naples, Italy
- NIOZ Royal Netherlands Institute for Sea Research, Den Burg, Netherlands
| | - Angela Sardo
- Stazione Zoologica Anton Dohrn Napoli (SZN), Naples, Italy
| | - Martina Blasio
- Stazione Zoologica Anton Dohrn Napoli (SZN), Naples, Italy
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Yu Z, Zhang T, Zhu Y. Whole-genome re-sequencing and transcriptome reveal cadmium tolerance related genes and pathways in Chlamydomonas reinhardtii. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 191:110231. [PMID: 31981954 DOI: 10.1016/j.ecoenv.2020.110231] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 01/16/2020] [Accepted: 01/17/2020] [Indexed: 06/10/2023]
Abstract
Cadmium (Cd), a common environmental toxic contaminant, is easily accumulated in living organisms, leading to numerous harmful effects. Chlamydomonas reinhardtii, a unicellular eukaryotic green algae strain, is a very suitable candidate for bioremediation of Cd-contaminated water. However, for the poor resistance to Cd, application of C. reinhardtii was restricted and genes mediating Cd tolerance in C. reinhardtii remain unclear. In this paper, adaptive laboratory evolution was performed with algae constant exposure to Cd over 420-day at environmentally relevant concentrations to select C. reinhardtii strains with high tolerance to Cd. Physiological indicators, such as cell proliferation, photosynthetic pigment contents and photosynthetic activity of photosystem were detected to evaluate the Cd tolerance of selected algae strain ALE0.5. Then, whole-genome re-sequencing and transcriptome were applied to identify the genes related to Cd tolerance. Genes involved in photosynthesis (PSBP1), glutathione metabolism (CHLREDRAFT_167073, GPX5) and calcium transport (CHLREDRAFT_189266, CHLREDRAFT_191203, CHLREDRAFT_187187, CSE1) were related to Cd tolerance in C. reinhardtii. This study provides a basis for obtaining transgenic C. reinhardtii strains with high Cd tolerance used for bioremediation of Cd pollution in the future.
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Affiliation(s)
- Zhen Yu
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China; School of Grain Science and Technology, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Teng Zhang
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Yi Zhu
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.
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20
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Toxicity, Physiological, and Ultrastructural Effects of Arsenic and Cadmium on the Extremophilic Microalga Chlamydomonas acidophila. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17051650. [PMID: 32138382 PMCID: PMC7084474 DOI: 10.3390/ijerph17051650] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 02/20/2020] [Accepted: 02/24/2020] [Indexed: 01/23/2023]
Abstract
The cytotoxicity of cadmium (Cd), arsenate (As(V)), and arsenite (As(III)) on a strain of Chlamydomonas acidophila, isolated from the Rio Tinto, an acidic environment containing high metal(l)oid concentrations, was analyzed. We used a broad array of methods to produce complementary information: cell viability and reactive oxygen species (ROS) generation measures, ultrastructural observations, transmission electron microscopy energy dispersive x-ray microanalysis (TEM-XEDS), and gene expression. This acidophilic microorganism was affected differently by the tested metal/metalloid: It showed high resistance to arsenic while Cd was the most toxic heavy metal, showing an LC50 = 1.94 µM. Arsenite was almost four-fold more toxic (LC50= 10.91 mM) than arsenate (LC50 = 41.63 mM). Assessment of ROS generation indicated that both arsenic oxidation states generate superoxide anions. Ultrastructural analysis of exposed cells revealed that stigma, chloroplast, nucleus, and mitochondria were the main toxicity targets. Intense vacuolization and accumulation of energy reserves (starch deposits and lipid droplets) were observed after treatments. Electron-dense intracellular nanoparticle-like formation appeared in two cellular locations: inside cytoplasmic vacuoles and entrapped into the capsule, around each cell. The chemical nature (Cd or As) of these intracellular deposits was confirmed by TEM-XEDS. Additionally, they also contained an unexpected high content in phosphorous, which might support an essential role of poly-phosphates in metal resistance.
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21
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Dean AP, Hartley A, McIntosh OA, Smith A, Feord HK, Holmberg NH, King T, Yardley E, White KN, Pittman JK. Metabolic adaptation of a Chlamydomonas acidophila strain isolated from acid mine drainage ponds with low eukaryotic diversity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 647:75-87. [PMID: 30077857 DOI: 10.1016/j.scitotenv.2018.07.445] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 07/30/2018] [Accepted: 07/30/2018] [Indexed: 06/08/2023]
Abstract
The diversity and biological characteristics of eukaryotic communities within acid mine drainage (AMD) sites is less well studied than for prokaryotic communities. Furthermore, for many eukaryotic extremophiles the potential mechanisms of adaptation are unclear. This study describes an evaluation of eight highly acidic (pH 1.6-3.1) and one moderately acidic (pH 5.6) metal-rich acid mine drainage ponds at a disused copper mine. The severity of AMD pollution on eukaryote biodiversity was examined, and while the most species-rich site was less acidic, biodiversity did not only correlate with pH but also with the concentration of dissolved and particulate metals. Acid-tolerant microalgae were present in all ponds, including the species Chlamydomonas acidophila, abundance of which was high in one very metal-rich and highly acidic (pH 1.6) pond, which had a particularly high PO4-P concentration. The C. acidophila strain named PM01 had a broad-range pH tolerance and tolerance to high concentrations of Cd, Cu and Zn, with bioaccumulation of these metals within the cell. Comparison of metal tolerance between the isolated strain and other C. acidophila strains previously isolated from different acidic environments found that the new strain exhibited much higher Cu tolerance, suggesting adaptation by C. acidophila PM01 to excess Cu. An analysis of the metabolic profile of the strains in response to increasing concentrations of Cu suggests that this tolerance by PM01 is in part due to metabolic adaptation and changes in protein content and secondary structure.
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Affiliation(s)
- Andrew P Dean
- School of Science and the Environment, Manchester Metropolitan University, Oxford Road, Manchester M1 5GD, UK
| | - Antoni Hartley
- School of Earth and Environmental Sciences, Faculty of Science and Engineering, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Owen A McIntosh
- School of Earth and Environmental Sciences, Faculty of Science and Engineering, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Alyssa Smith
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Helen K Feord
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Nicolas H Holmberg
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Thomas King
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Ellen Yardley
- Department of Geography, University of Sheffield, Sheffield S10 2TN, UK
| | - Keith N White
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK; School of Earth and Environmental Sciences, Faculty of Science and Engineering, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Jon K Pittman
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK; School of Earth and Environmental Sciences, Faculty of Science and Engineering, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK.
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Puente-Sánchez F, Díaz S, Penacho V, Aguilera A, Olsson S. Basis of genetic adaptation to heavy metal stress in the acidophilic green alga Chlamydomonas acidophila. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2018; 200:62-72. [PMID: 29727772 DOI: 10.1016/j.aquatox.2018.04.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 04/24/2018] [Accepted: 04/25/2018] [Indexed: 05/26/2023]
Abstract
To better understand heavy metal tolerance in Chlamydomonas acidophila, an extremophilic green alga, we assembled its transcriptome and measured transcriptomic expression before and after Cd exposure in this and the neutrophilic model microalga Chlamydomonas reinhardtii. Genes possibly related to heavy metal tolerance and detoxification were identified and analyzed as potential key innovations that enable this species to live in an extremely acid habitat with high levels of heavy metals. In addition we provide a data set of single orthologous genes from eight green algal species as a valuable resource for comparative studies including eukaryotic extremophiles. Our results based on differential gene expression, detection of unique genes and analyses of codon usage all indicate that there are important genetic differences in C. acidophila compared to C. reinhardtii. Several efflux family proteins were identified as candidate key genes for adaptation to acid environments. This study suggests for the first time that exposure to cadmium strongly increases transposon expression in green algae, and that oil biosynthesis genes are induced in Chlamydomonas under heavy metal stress. Finally, the comparison of the transcriptomes of several acidophilic and non-acidophilic algae showed that the Chlamydomonas genus is polyphyletic and that acidophilic algae have distinctive aminoacid usage patterns.
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MESH Headings
- Actins/genetics
- Actins/metabolism
- Adaptation, Physiological/drug effects
- Cadmium/metabolism
- Cadmium/toxicity
- Carboxylic Ester Hydrolases/classification
- Carboxylic Ester Hydrolases/genetics
- Chlamydomonas/classification
- Chlamydomonas/drug effects
- Chlamydomonas/metabolism
- Dioxygenases/classification
- Dioxygenases/genetics
- Drug Tolerance/genetics
- Metals, Heavy/metabolism
- Metals, Heavy/toxicity
- Phylogeny
- Plant Proteins/classification
- Plant Proteins/genetics
- RNA, Plant/chemistry
- RNA, Plant/isolation & purification
- RNA, Plant/metabolism
- RNA, Ribosomal, 18S/genetics
- RNA, Ribosomal, 18S/metabolism
- Sequence Analysis, RNA
- Transcriptome/drug effects
- Water Pollutants, Chemical/chemistry
- Water Pollutants, Chemical/metabolism
- Water Pollutants, Chemical/toxicity
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Affiliation(s)
- Fernando Puente-Sánchez
- Systems Biology Program, Centro Nacional de Biotecnología (CNB-CSIC), Calle Darwin 3, 28049, Madrid, Spain
| | - Silvia Díaz
- Department of Physiology, Genetics and Microbiology, Complutense University of Madrid (UCM), Calle José Antonio Novais 12, 28040 Madrid, Spain
| | - Vanessa Penacho
- Bioarray, S.L. Parque Científico y Empresarial de la UMH, Edificio Quorum III, Avenida de la Universidad s/n, 03202 Elche, Alicante, Spain
| | - Angeles Aguilera
- Centro de Astrobiología (CSIC-INTA), Carretera de Ajalvir Km 4, 28850 Torrejón de Ardoz, Madrid, Spain
| | - Sanna Olsson
- INIA Forest Research Centre (INIA-CIFOR), Department Forest Ecology and Genetics, Carretera de la Coruña km 7.5, 28040 Madrid, Spain; Department Agricultural Sciences, P.O. Box 27, 00014 University of Helsinki, Finland.
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23
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Fontanini D, Andreucci A, Ruffini Castiglione M, Basile A, Sorbo S, Petraglia A, Degola F, Bellini E, Bruno L, Varotto C, Sanità di Toppi L. The phytochelatin synthase from Nitella mucronata (Charophyta) plays a role in the homeostatic control of iron(II)/(III). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2018; 127:88-96. [PMID: 29554573 DOI: 10.1016/j.plaphy.2018.03.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 03/10/2018] [Accepted: 03/12/2018] [Indexed: 06/08/2023]
Abstract
Although some charophytes (sister group to land plants) have been shown to synthesize phytochelatins (PCs) in response to cadmium (Cd), the functional characterization of their phytochelatin synthase (PCS) is still completely lacking. To investigate the metal response and the presence of PCS in charophytes, we focused on the species Nitella mucronata. A 40 kDa immunoreactive PCS band was revealed in mono-dimensional western blot by using a polyclonal antibody against Arabidopsis thaliana PCS1. In two-dimensional western blot, the putative PCS showed various spots with acidic isoelectric points, presumably originated by post-translational modifications. Given the PCS constitutive expression in N. mucronata, we tested its possible involvement in the homeostasis of metallic micronutrients, using physiological concentrations of iron (Fe) and zinc (Zn), and verified its role in the detoxification of a non-essential metal, such as Cd. Neither in vivo nor in vitro exposure to Zn resulted in PCS activation and PC significant biosynthesis, while Fe(II)/(III) and Cd were able to activate the PCS in vitro, as well as to induce PC accumulation in vivo. While Cd toxicity was evident from electron microscopy observations, the normal morphology of cells and organelles following Fe treatments was preserved. The overall results support a function of PCS and PCs in managing Fe homeostasis in the carophyte N. mucronata.
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Affiliation(s)
| | | | | | - Adriana Basile
- Department of Biology, University of Naples "Federico II", Naples, Italy
| | - Sergio Sorbo
- CeSMA, Microscopy Section, University of Naples "Federico II", Naples, Italy
| | - Alessandro Petraglia
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Francesca Degola
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Erika Bellini
- Department of Biology, University of Pisa, Pisa, Italy; Department of Biology, University of Rome "Tor Vergata", Rome, Italy
| | - Laura Bruno
- Department of Biology, University of Rome "Tor Vergata", Rome, Italy
| | - Claudio Varotto
- Department of Biodiversity and Molecular Ecology, "Edmund Mach" Foundation, S. Michele all'Adige (TN), Italy
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24
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Abinandan S, Subashchandrabose SR, Venkateswarlu K, Megharaj M. Microalgae-bacteria biofilms: a sustainable synergistic approach in remediation of acid mine drainage. Appl Microbiol Biotechnol 2018; 102:1131-1144. [PMID: 29260261 DOI: 10.1007/s00253-017-8693-] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 12/03/2017] [Accepted: 12/04/2017] [Indexed: 05/28/2023]
Abstract
Microalgae and bacteria offer a huge potential in delving interest to study and explore various mechanisms under extreme environments. Acid mine drainage (AMD) is one such environment which is extremely acidic containing copious amounts of heavy metals and poses a major threat to the ecosystem. Despite its extreme conditions, AMD is the habitat for several microbes and their activities. The use of various chemicals in prevention of AMD formation and conventional treatment in a larger scale is not feasible under different geological conditions. It implies that microbe-mediated approach is a viable and sustainable alternative technology for AMD remediation. Microalgae in biofilms play a pivotal role in such bioremediation as they maintain mutualism with heterotrophic bacteria. Synergistic approach of using microalgae-bacteria biofilms provides supportive metabolites from algal biomass for growth of bacteria and mediates remediation of AMD. However, by virtue of their physiology and capabilities of metal removal, non-acidophilic microalgae can be acclimated for use in AMD remediation. A combination of selective acidophilic and non-acidophilic microalgae together with bacteria, all in the form of biofilms, may be very effective for bioremediation of metal-contaminated waters. The present review critically examines the nature of mutualistic interactions established between microalgae and bacteria in biofilms and their role in removal of metals from AMDs, and consequent biomass production for the yield of biofuel. Integration of microalgal-bacterial consortia in fuel cells would be an attractive emerging approach of microbial biotechnology for AMD remediation.
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Affiliation(s)
- Sudharsanam Abinandan
- Global Centre for Environmental Remediation (GCER), Faculty of Science, University of Newcastle, ATC Building, University Drive, Callaghan, NSW, 2308, Australia
| | - Suresh R Subashchandrabose
- Global Centre for Environmental Remediation (GCER), Faculty of Science, University of Newcastle, ATC Building, University Drive, Callaghan, NSW, 2308, Australia
- Cooperative Research Centre for Contamination Assessment and Remediation of Environment (CRC CARE), University of Newcastle, ATC Building, University Drive, Callaghan, NSW, 2308, Australia
| | - Kadiyala Venkateswarlu
- Formerly Department of Microbiology, Sri Krishnadevaraya University, Anantapur, 515055, India
| | - Mallavarapu Megharaj
- Global Centre for Environmental Remediation (GCER), Faculty of Science, University of Newcastle, ATC Building, University Drive, Callaghan, NSW, 2308, Australia.
- Cooperative Research Centre for Contamination Assessment and Remediation of Environment (CRC CARE), University of Newcastle, ATC Building, University Drive, Callaghan, NSW, 2308, Australia.
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25
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Microalgae-bacteria biofilms: a sustainable synergistic approach in remediation of acid mine drainage. Appl Microbiol Biotechnol 2017; 102:1131-1144. [PMID: 29260261 DOI: 10.1007/s00253-017-8693-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 12/03/2017] [Accepted: 12/04/2017] [Indexed: 10/18/2022]
Abstract
Microalgae and bacteria offer a huge potential in delving interest to study and explore various mechanisms under extreme environments. Acid mine drainage (AMD) is one such environment which is extremely acidic containing copious amounts of heavy metals and poses a major threat to the ecosystem. Despite its extreme conditions, AMD is the habitat for several microbes and their activities. The use of various chemicals in prevention of AMD formation and conventional treatment in a larger scale is not feasible under different geological conditions. It implies that microbe-mediated approach is a viable and sustainable alternative technology for AMD remediation. Microalgae in biofilms play a pivotal role in such bioremediation as they maintain mutualism with heterotrophic bacteria. Synergistic approach of using microalgae-bacteria biofilms provides supportive metabolites from algal biomass for growth of bacteria and mediates remediation of AMD. However, by virtue of their physiology and capabilities of metal removal, non-acidophilic microalgae can be acclimated for use in AMD remediation. A combination of selective acidophilic and non-acidophilic microalgae together with bacteria, all in the form of biofilms, may be very effective for bioremediation of metal-contaminated waters. The present review critically examines the nature of mutualistic interactions established between microalgae and bacteria in biofilms and their role in removal of metals from AMDs, and consequent biomass production for the yield of biofuel. Integration of microalgal-bacterial consortia in fuel cells would be an attractive emerging approach of microbial biotechnology for AMD remediation.
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Acidophilic green algal genome provides insights into adaptation to an acidic environment. Proc Natl Acad Sci U S A 2017; 114:E8304-E8313. [PMID: 28893987 DOI: 10.1073/pnas.1707072114] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Some microalgae are adapted to extremely acidic environments in which toxic metals are present at high levels. However, little is known about how acidophilic algae evolved from their respective neutrophilic ancestors by adapting to particular acidic environments. To gain insights into this issue, we determined the draft genome sequence of the acidophilic green alga Chlamydomonas eustigma and performed comparative genome and transcriptome analyses between Ceustigma and its neutrophilic relative Chlamydomonas reinhardtii The results revealed the following features in Ceustigma that probably contributed to the adaptation to an acidic environment. Genes encoding heat-shock proteins and plasma membrane H+-ATPase are highly expressed in Ceustigma This species has also lost fermentation pathways that acidify the cytosol and has acquired an energy shuttle and buffering system and arsenic detoxification genes through horizontal gene transfer. Moreover, the arsenic detoxification genes have been multiplied in the genome. These features have also been found in other acidophilic green and red algae, suggesting the existence of common mechanisms in the adaptation to acidic environments.
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