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Firth AJ, Nakasu PYS, Fennell PS, Hallett JP. An Ionic Liquid-Based Biorefinery Approach for Duckweed Utilization. ACS SUSTAINABLE RESOURCE MANAGEMENT 2024; 1:842-856. [PMID: 38807756 PMCID: PMC11129354 DOI: 10.1021/acssusresmgt.3c00008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 04/06/2024] [Accepted: 04/08/2024] [Indexed: 05/30/2024]
Abstract
This study establishes a foundation for the ionic liquid (IL) pretreatment of duckweed biomass. An optimized IL-based process was designed to exploit the unique properties of duckweed including efficient metal removal, potential starch accumulation, and protein accumulation. Two ILs, namely, dimethylethanolammonium formate ([DMEtA][HCOO]) and N,N-dimethylbutylammonium hydrogen sulfate ([DMBA][HSO4]), were investigated for the pretreatment of two duckweed species (Spirodela polyrhiza and Lemna minor). The evaluation focused on starch recovery, sugar release, protein recovery, and metal extraction capabilities. [DMEtA][HCOO] demonstrated near-quantitative starch recoveries at 120 °C, while [DMBA][HSO4] showed similar performance at 90 °C within a reaction time of 2 h. Saccharification yields for most pulps exceeded 90% after 8 h of hydrolysis, outperforming "traditional" lignocellulosic biomasses such as miscanthus or sugarcane bagasse. Approximately 50 and 80 wt % of the protein were solubilized in [DMEtA][HCOO] and [DMBA][HSO4], respectively, while the remaining protein distributed between the pulp and lignin. However, the solubilized protein in the IL could not be recovered due to its low molecular weight. Regarding metal extraction, [DMEtA][HCOO] demonstrated higher efficiency, achieving 81% removal of Ni from Lemna minor's pulps, whereas [DMBA][HSO4] extracted only 28% of Ni with slightly higher pulp concentrations. These findings indicate the need for further optimization in concurrent metal extraction using ILs.
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Affiliation(s)
- Anton
E. J. Firth
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Pedro Y. S. Nakasu
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Paul S. Fennell
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Jason P. Hallett
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, United Kingdom
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Yang J, Zhao X, Wang X, Xia M, Ba S, Lim BL, Hou H. Biomonitoring of heavy metals and their phytoremediation by duckweeds: Advances and prospects. ENVIRONMENTAL RESEARCH 2024; 245:118015. [PMID: 38141920 DOI: 10.1016/j.envres.2023.118015] [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: 08/30/2023] [Revised: 12/13/2023] [Accepted: 12/21/2023] [Indexed: 12/25/2023]
Abstract
Heavy metals (HMs) contamination of water bodies severely threatens human and ecosystem health. There is growing interest in the use of duckweeds for HMs biomonitoring and phytoremediation due to their fast growth, low cultivation costs, and excellent HM uptake efficiency. In this review, we summarize the current state of knowledge on duckweeds and their suitability for HM biomonitoring and phytoremediation. Duckweeds have been used for phytotoxicity assays since the 1930s. Some toxicity tests based on duckweeds have been listed in international guidelines. Duckweeds have also been recognized for their ability to facilitate HM phytoremediation in aquatic environments. Large-scale screening of duckweed germplasm optimized for HM biomonitoring and phytoremediation is still essential. We further discuss the morphological, physiological, and molecular effects of HMs on duckweeds. However, the existing data are clearly insufficient, especially in regard to dissection of the transcriptome, metabolome, proteome responses and molecular mechanisms of duckweeds under HM stresses. We also evaluate the influence of environmental factors, exogenous substances, duckweed community composition, and HM interactions on their HM sensitivity and HM accumulation, which need to be considered in practical application scenarios. Finally, we identify challenges and propose approaches for improving the effectiveness of duckweeds for bioremediation from the aspects of selection of duckweed strain, cultivation optimization, engineered duckweeds. We foresee great promise for duckweeds as phytoremediation agents, providing environmentally safe and economically efficient means for HM removal. However, the primary limiting issue is that so few researchers have recognized the outstanding advantages of duckweeds. We hope that this review can pique the interest and attention of more researchers.
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Affiliation(s)
- Jingjing Yang
- The State Key Laboratory of Freshwater Ecology and Biotechnology, The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
| | - Xuyao Zhao
- The State Key Laboratory of Freshwater Ecology and Biotechnology, The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
| | - Xiaoyu Wang
- The State Key Laboratory of Freshwater Ecology and Biotechnology, The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
| | - Manli Xia
- The State Key Laboratory of Freshwater Ecology and Biotechnology, The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
| | - Sang Ba
- Center for Carbon Neutrality in the Third Pole of the Earth, Tibet University, Lhasa, 850000, China; Laboratory of Tibetan Plateau Wetland and Watershed Ecosystem, College of Science, Tibet University, Lhasa, 850000, China.
| | - Boon Leong Lim
- School of Biological Sciences, University of Hong Kong, Hong Kong, China; HKU Shenzhen Institute of Research and Innovation, Shenzhen, China; State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China.
| | - Hongwei Hou
- The State Key Laboratory of Freshwater Ecology and Biotechnology, The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
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Irfan M, Mészáros I, Szabó S, Oláh V. Comparative Phytotoxicity of Metallic Elements on Duckweed Lemna gibba L. Using Growth- and Chlorophyll Fluorescence Induction-Based Endpoints. PLANTS (BASEL, SWITZERLAND) 2024; 13:215. [PMID: 38256768 PMCID: PMC10821045 DOI: 10.3390/plants13020215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/06/2024] [Accepted: 01/07/2024] [Indexed: 01/24/2024]
Abstract
In this study, we exposed a commonly used duckweed species-Lemna gibba L.-to twelve environmentally relevant metals and metalloids under laboratory conditions. The phytotoxic effects were evaluated in a multi-well-plate-based experimental setup by means of the chlorophyll fluorescence imaging method. This technique allowed the simultaneous measuring of the growth and photosynthetic parameters in the same samples. The inhibition of relative growth rates (based on frond number and area) and photochemical efficiency (Fv/Fo and Y(II)) were both calculated from the obtained chlorophyll fluorescence images. In the applied test system, growth-inhibition-based phytotoxicity endpoints proved to be more sensitive than chlorophyll-fluorescence-based ones. Frond area growth inhibition was the most responsive parameter with a median EC50 of 1.75 mg L-1, while Fv/Fo, the more responsive chlorophyll-fluorescence-based endpoint, resulted in a 5.34 mg L-1 median EC50 for the tested metals. Ag (EC50 0.005-1.27 mg L-1), Hg (EC50 0.24-4.87 mg L-1) and Cu (EC50 0.37-1.86 mg L-1) were the most toxic elements among the tested ones, while As(V) (EC50 47.15-132.18 mg L-1), Cr(III) (EC50 6.22-19.92 mg L-1), Se(VI) (EC50 1.73-10.39 mg L-1) and Zn (EC50 3.88-350.56 mg L-1) were the least toxic ones. The results highlighted that multi-well-plate-based duckweed phytotoxicity assays may reduce space, time and sample volume requirements compared to the standard duckweed growth inhibition tests. These benefits, however, come with lowered test sensitivity. Our multi-well-plate-based test setup resulted in considerably higher median EC50 (3.21 mg L-1) for frond-number-based growth inhibition than the 0.683 mg L-1 median EC50 derived from corresponding data from the literature with standardized Lemna-tests. Under strong acute phytotoxicity, frond parts with impaired photochemical functionality may become undetectable by chlorophyll fluorometers. Consequently, the plant parts that are still detectable display a virtually higher average photosynthetic performance, leading to an underestimation of phytotoxicity. Nevertheless, multi-well-plate-based duckweed phytotoxicity assays, combined with chlorophyll fluorescence imaging, offer definite advantages in the rapid screening of large sample series or multiple species/clones. As chlorophyll fluorescence images provide information both on the photochemical performance of the test plants and their morphology, a joint analysis of the two endpoint groups is recommended in multi-well-plate-based duckweed phytotoxicity assays to maximize the information gained from the tests.
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Affiliation(s)
- Muhammad Irfan
- Department of Botany, Institute of Biology and Ecology, Faculty of Science and Technology, University of Debrecen, Egyetem Square 1, H-4032 Debrecen, Hungary; (M.I.); (I.M.)
| | - Ilona Mészáros
- Department of Botany, Institute of Biology and Ecology, Faculty of Science and Technology, University of Debrecen, Egyetem Square 1, H-4032 Debrecen, Hungary; (M.I.); (I.M.)
| | - Sándor Szabó
- Department of Biology, Institute of Environmental Sciences, University of Nyiregyhaza, H-4401 Nyiregyhaza, Hungary
| | - Viktor Oláh
- Department of Botany, Institute of Biology and Ecology, Faculty of Science and Technology, University of Debrecen, Egyetem Square 1, H-4032 Debrecen, Hungary; (M.I.); (I.M.)
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Adomako MO, Yu FH. Effects of resource availability on the growth, Cd accumulation, and photosynthetic efficiency of three hyperaccumulator plant species. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 345:118762. [PMID: 37591095 DOI: 10.1016/j.jenvman.2023.118762] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 07/26/2023] [Accepted: 08/09/2023] [Indexed: 08/19/2023]
Abstract
Plants that hyperaccumulate heavy metals such as cadmium (Cd) are important agents of phytoremediation. Availability of resources such as light, nutrients, and water can affect heavy metal accumulation by plants, but the responses of hyperaccumulators to different levels of resource availability remain little studied. To test such responses, three Cd hyperaccumulators, Solanum nigrum, Bidens pilosa, and Taraxacum mongolicum, were grown in Cd-contaminated soil; subjected to three levels of light, nutrient, or water availability; and measured for growth, Cd accumulation, and photosynthetic efficiency. All three species accumulated more total biomass and grew taller if given high than low water or light (each P < 0.001). Species accumulated four to eight times more Cd (190-309 versus 24-68 μg Cd g-1 mass) under high than low light. High water availability increased Cd accumulation by 89% in B. pilosa but decreased it by 31% and 40% in S. nigrum and B. pilosa, respectively. Effects of nutrients on both growth and accumulation varied between species; Cd accumulation by S. nigrum and T. mongolicum was respectively 14% and 54% lower at high than low nutrients, while it was 130% higher in B. pilosa. Light but not water or nutrient availability affected effective and maximum quantum yields and electron transport rate. Findings from this study suggest that low levels of light may constrain phytoremediation of Cd in soil and that testing species of Cd hyperaccumulators individually for responses to levels of water and nutrients will inform selection of species for phytoremediation.
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Affiliation(s)
- Michael Opoku Adomako
- Institute of Wetland Ecology & Clone Ecology/Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, Taizhou, 318000, Zhejiang, China
| | - Fei-Hai Yu
- Institute of Wetland Ecology & Clone Ecology/Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, Taizhou, 318000, Zhejiang, China.
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Varga M, Žuna Pfeiffer T, Begović L, Mlinarić S, Horvatić J, Miloloža T, Štolfa Čamagajevac I. Physiological Response of Nutrient-Stressed Lemna gibba to Pulse Colloidal Silver Treatment. PLANTS (BASEL, SWITZERLAND) 2023; 12:1367. [PMID: 36987055 PMCID: PMC10055381 DOI: 10.3390/plants12061367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/23/2023] [Accepted: 03/17/2023] [Indexed: 06/19/2023]
Abstract
Wastewater is a source of many environmental pollutants and potentially high concentrations of essential plant nutrients. Site-specific nutrient levels may influence the response of exposed plants to a chemical stressor. In the present study, we focused on the responses of model aquatic macrophyte swollen duckweed (Lemna gibba L.) to a short pulse exposure and a commercially available colloidal silver product as a potential environmental chemical stressor, combined with two levels of total nitrogen and phosphorus nutrition. Treatment with the commercially available colloidal silver product caused oxidative stress in L. gibba plants under both high and low nutrient levels. Plants grown and treated under high nutrient levels showed lower levels of lipid peroxidation and hydrogen peroxide accumulation, as well as higher levels of photosynthetic pigment content in comparison to treated plants under low nutrient levels. Higher free radical scavenging activity for plants treated with silver in combination with high nutrient levels resulted in better overall protection from silver-induced oxidative stress. The results showed that external nutrient levels significantly affected the L. gibba plant's response to the colloidal silver presence in the environment and that nutrient levels should be considered in the assessment of potential environmental impact for contaminants.
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