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Lu J, Mu X, Zhang S, Song Y, Ma Y, Luo M, Duan R. Coupling of submerged macrophytes and epiphytic biofilms reduced methane emissions from wetlands: Evidenced by an antibiotic inhibition experiment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 904:166710. [PMID: 37652383 DOI: 10.1016/j.scitotenv.2023.166710] [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: 06/22/2023] [Revised: 08/24/2023] [Accepted: 08/28/2023] [Indexed: 09/02/2023]
Abstract
Wetlands are the largest natural methane source, but how submerged macrophytes affect methane emission remains controversial. In this study, the impacts of submerged macrophytes on methane fluxes, water purification, and epiphytic microbial community dynamics were investigated in simulated wetlands (with and without Hydrilla verticillata) treated with norfloxacin (NOR) for 24 days. Mean methane fluxes were significantly lower in treatments with Hydrilla verticillata (56.84-90.94 mg/m2/h) than bulks (65.96-113.21 mg/m2/h) (p < 0.05) during the experiment regardless of NOR. The relative conductivity (REC) values, H2O2, and malondialdehyde (MDA) contents increased in plant leaves, while water nutrients removal rates decreased with increasing NOR concentration at the same sampling time. The partial least squares path model analysis revealed that plant physiological indices and water nutrients positively affected methane fluxes (0.72 and 0.49, p < 0.001). According to illumina sequencing results of 16S rRNA and pmoA genes, α-proteobacteria (type II) and γ-proteobacteria (type I) were the dominant methanotroph classes in all epiphytic biofilms. The ratio of type I/type II methanotrophs and pmoA gene abundance in epiphytic biofilm was considerably lower in treatment with 16 mg/L NOR than without it (p < 0.05). pmoA gene abundance was negatively correlated with methane fluxes (p < 0.05). Additionally, the assembly of epiphytic bacterial community was mainly governed by deterministic processes, while stochastic dispersal limitation was the primary assembly process in the epiphytic methanotrophic community under NOR stress. The deterministic process gained more importance with time both in bacterial and methanotrophic community assembly. Network analysis revealed that relationships among bacteria in epiphytic biofilms weakened with time but associations among methanotrophic members were enhanced under NOR stress over time. It could be concluded that submerged macrophytes-epiphytic biofilms symbiotic system exhibited potential prospects to reduce methane emissions from wetlands under reasonable management.
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Affiliation(s)
- Jianhui Lu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
| | - Xiaoying Mu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
| | - Songhe Zhang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China.
| | - Yingying Song
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
| | - Yu Ma
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
| | - Min Luo
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
| | - Rufei Duan
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
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Barros-Rodríguez A, García-Gálvez C, Pacheco P, Kalyuzhnaya MG, Manzanera M. Isolation of Methane Enriched Bacterial Communities and Application as Wheat Biofertilizer under Drought Conditions: An Environmental Contribution. PLANTS (BASEL, SWITZERLAND) 2023; 12:2487. [PMID: 37447048 DOI: 10.3390/plants12132487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 06/23/2023] [Accepted: 06/27/2023] [Indexed: 07/15/2023]
Abstract
The search for methanotrophs as plant-growth-promoting rhizobacteria (PGPR) presents an important contribution to mitigating the impact of global warming by restoring the natural soil potential for consuming methane while benefiting plants during droughts. Our in silico simulations suggest that water, produced as a byproduct of methane oxidation, can satisfy the cell growth requirement. In addition to water, methanotrophs can produce metabolites that stimulate plant growth. Considering this, we proposed that applying methanotrophs as PGPR can alleviate the effect of droughts on crops, while stimulating atmospheric methane consumption. In this work, we isolated a series of methanotrophic communities from the rhizospheres of different crops, including Italian sweet pepper and zucchini, using an atmosphere enriched with pure methane gas, to determine their potential for alleviating drought stress in wheat plants. Subsequently, 23 strains of nonmethanotrophic bacteria present in the methanotrophic communities were isolated and characterized. We then analyzed the contribution of the methane-consuming consortia to the improvement of plant growth under drought conditions, showing that some communities contributed to increases in the wheat plants' lengths and weights, with statistically significant differences according to ANOVA models. Furthermore, we found that the presence of methane gas can further stimulate the plant-microbe interactions, resulting in larger plants and higher drought tolerance.
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Affiliation(s)
- Adoración Barros-Rodríguez
- Institute for Water Research and Department of Microbiology, University of Granada, 18071 Granada, Spain
- VitaNtech Biotechnology S.L., 18008 Granada, Spain
| | - Carlos García-Gálvez
- Institute for Water Research and Department of Microbiology, University of Granada, 18071 Granada, Spain
- VitaNtech Biotechnology S.L., 18008 Granada, Spain
| | - Pamela Pacheco
- Institute for Water Research and Department of Microbiology, University of Granada, 18071 Granada, Spain
| | | | - Maximino Manzanera
- Institute for Water Research and Department of Microbiology, University of Granada, 18071 Granada, Spain
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Yang L, Zhang S, Lv X, Liu Y, Guo S, Hu X, Manirakiza B. Vallisneria natans decreased CH 4 fluxes in wetlands: Interactions among plant physiological status, nutrients and epiphytic bacterial community. ENVIRONMENTAL RESEARCH 2023; 224:115547. [PMID: 36822529 DOI: 10.1016/j.envres.2023.115547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/13/2023] [Accepted: 02/21/2023] [Indexed: 06/18/2023]
Abstract
Submerged macrophytes provide niches for epiphytic microbes (including aerobic methanotrophs) growth. However, little is known about the impacts of submerged macrophytes growth status and nutrients loadings on methanotroph community and methane release in wetlands. In the present study, methane fluxes, bacterial and methanotroph community in epiphytic biofilm, and environmental parameters were investigated during Vallisneria natans senescence in wetlands under low (VnL) and high (VnH) nutrients for seven weeks. Relative conductivity and concentration of H2O2, total chlorophyll and malondialdehyde were higher in leaves of V. natans in VnH than VnL at the same sampling time. Nutrients loading increased methane fluxes in treatments with or without (Control) macrophytes, while healthy V. natans plants reduced the methane flux and nutrients concentration in water columns. CH4 fluxes were positively correlated to temperature and COD (p < 0.05). Methane oxidation rates were 3.04-31.68 μmol methane mg-1 fresh weight of V. natans leaves - epiphytic biofilm within 1 h. Proteobacteria, Cyanobacteria, Bacteroidetes, Verrucomicrobia, Planctomycetes, Actinobacteria and Acidobacteria were dominant phylum in all epiphytic biofilms. The mean abundances of pmoA/16S rRNA were higher in VnL than VnH. According to Illumina sequencing results of pmoA gene, γ-proteobacteria and α-proteobacteria were the dominant methanotroph class in epiphytic biofilm from VnH and VnL, respectively. Among seven detected methanotrophic genera, Methylomonas was significantly higher in VnH than VnL. Network analysis revealed that there were much closer relationships between the environmental parameters and epiphytic bacterial community in VnH than in VnL. COD and MDA were negatively correlated with Methyloglobulus, Methylosarcina, Methylobacter and Methylocystis, but positively correlated with Methylomonas and Methylosinus. This study highlights that methanotrophs in epiphytic biofilm play important roles in methane-oxidizing, which can be affected by plant physiological status and environmental parameters.
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Affiliation(s)
- Liu Yang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, PR China; College of Environment, Hohai University, Nanjing, 210098, PR China
| | - Songhe Zhang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, PR China; College of Environment, Hohai University, Nanjing, 210098, PR China.
| | - Xin Lv
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, PR China; College of Environment, Hohai University, Nanjing, 210098, PR China
| | - Yuansi Liu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, PR China; College of Environment, Hohai University, Nanjing, 210098, PR China
| | - Shaozhuang Guo
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, PR China; College of Environment, Hohai University, Nanjing, 210098, PR China
| | - Xiuren Hu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, PR China; College of Environment, Hohai University, Nanjing, 210098, PR China
| | - Benjamin Manirakiza
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, PR China; College of Environment, Hohai University, Nanjing, 210098, PR China
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Zhu J, Li Y, Huang M, Xu D, Zhang Y, Zhou Q, Wu Z, Wang C. Restoration effects of submerged macrophytes on methane production and oxidation potential of lake sediments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 866:161218. [PMID: 36584953 DOI: 10.1016/j.scitotenv.2022.161218] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 06/17/2023]
Abstract
The restoration of submerged macrophytes is an important step in lake ecosystem restoration, during which artificially assisted measures have been widely used for macrophyte recolonization. Compared with natural restoration, the impact of artificially assisted methods on methane (CH4) production and oxidation of lake sediments remains unclear. Therefore, after the restoration of submerged macrophytes in some parts of West Lake (Hangzhou, China), sediment samples from West Lake were collected according to restoration methods and plant coverage. The CH4 production potential, oxidation potential, and microbial community structure in the sediment were discussed through whole-lake sample analysis and resampling verification from typical lake areas. From the analysis of the whole lake, the average daily CH4 production potential (ADP) of artificially restored lake areas (0.12 μg g-1 d-1) was significantly lower than that of the naturally restored lake areas (0.52 μg g-1 d-1). From the resampling analysis of typical lake areas, the ADP of naturally restored lake areas was 1.8 times that of artificially restored lake areas (P < 0.01). Although there was no significant difference in the CH4 oxidation potential between the two restoration methods, the presence of submerged macrophytes significantly increased the abundance of the dominant methanotroph Methylocaldum in the sediment, and the rate of increase in the abundance of the dominant methanotroph Methylosinus was significantly higher in artificially assisted restoration than in natural restoration. This study revealed that the artificially assisted restoration of submerged macrophytes reduced the potential for CH4 production and increased the abundance of dominant methanotrophs in the lake sediment, which would be beneficial for the reduction of CH4 emissions during lake ecological restoration and environmental management.
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Affiliation(s)
- Jianglong Zhu
- Faculty of Resources and Environmental Science, Hubei University, No. 368 Youyi Avenue, Wuchang District, Wuhan 430062, China; Hubei Key Laboratory of Regional Development and Environmental Response, Hubei University, No. 368 Youyi Avenue, Wuchang District, Wuhan 430062, China
| | - Yahua Li
- China University of Geosciences, No. 388 Lumo Road, Hongshan District, Wuhan 430074, China
| | - Minghui Huang
- China University of Geosciences, No. 388 Lumo Road, Hongshan District, Wuhan 430074, China
| | - Dong Xu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, No. 7 Donghu South Road, Wuchang District, Wuhan 430072, China
| | - Yi Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, No. 7 Donghu South Road, Wuchang District, Wuhan 430072, China
| | - Qiaohong Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, No. 7 Donghu South Road, Wuchang District, Wuhan 430072, China
| | - Zhenbin Wu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, No. 7 Donghu South Road, Wuchang District, Wuhan 430072, China
| | - Chuan Wang
- Faculty of Resources and Environmental Science, Hubei University, No. 368 Youyi Avenue, Wuchang District, Wuhan 430062, China; Hubei Key Laboratory of Regional Development and Environmental Response, Hubei University, No. 368 Youyi Avenue, Wuchang District, Wuhan 430062, China; State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, No. 7 Donghu South Road, Wuchang District, Wuhan 430072, China.
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Yurimoto H, Sakai Y. Interaction between C1-microorganisms and plants: contribution to the global carbon cycle and microbial survival strategies in the phyllosphere. Biosci Biotechnol Biochem 2022; 87:1-6. [PMID: 36367545 DOI: 10.1093/bbb/zbac176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/02/2022] [Indexed: 11/13/2022]
Abstract
C1-microorganisms that can utilize C1-compounds, such as methane and methanol, are ubiquitous in nature, and contribute to drive the global carbon cycle between two major greenhouse gases, CO2 and methane. Plants emit C1-compounds from their leaves and provide habitats for C1-microorganisms. Among C1-microorganisms, Methylobacterium spp., representative of methanol-utilizing methylotrophic bacteria, predominantly colonize the phyllosphere and are known to promote plant growth. This review summarizes the interactions between C1-mircroorganisms and plants that affect not only the fixation of C1-compounds produced by plants but also CO2 fixation by plants. We also describe our recent understanding of the survival strategy of C1-microorganisms in the phyllosphere and the application of Methylobacterium spp. to improve rice crop yield.
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Affiliation(s)
- Hiroya Yurimoto
- D ivision of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto, Japan
| | - Yasuyoshi Sakai
- D ivision of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto, Japan
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Manirakiza B, Zhang S, Addo FG, Isabwe A, Nsabimana A. Exploring microbial diversity and ecological function of epiphytic and surface sediment biofilm communities in a shallow tropical lake. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 808:151821. [PMID: 34808175 DOI: 10.1016/j.scitotenv.2021.151821] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 11/14/2021] [Accepted: 11/16/2021] [Indexed: 06/13/2023]
Abstract
Microbial communities in epiphytic biofilms and surface sediments play a vital role in the biogeochemical cycles of the major chemical elements in freshwater. However, little is known about the diversity, composition, and ecological functions of microbial communities in shallow tropical lakes dominated by aquatic macrophytes. In this study, epiphytic bacterial and eukaryotic biofilm communities on submerged and floating macrophytes and surface sediments were investigated in Lake Rumira, Rwanda in August and November 2019. High-throughput sequencing data revealed that members of the phyla, including Firmicutes, Proteobacteria, Cyanobacteria, Actinobacteria, Chloroflexi, Bacteriodetes, Verrumicrobia, and Myxomycota, dominated bacterial communities, while the microeukaryotic communities were dominated by Unclassified (uncl) SAR(Stramenopiles, Alveolata, Rhizaria), Rotifers, Ascomycota, Gastrotricha, Platyhelminthes, Chloroplastida, and Arthropoda. Interestingly, the eukaryotic OTUs (operational taxonomic units) number and Shannon indices were significantly higher in sediments and epiphytic biofilms on Eicchornia crassipes than Ceratophyllum demersum (p < 0.05), while no differences were observed in bacterial OTUs number and Shannon values among substrates. Redundancy analysis (RDA) showed that water temperature, pH, dissolved oxygen (DO), total nitrogen (TN), and electrical conductivity (EC) were the most important abiotic factors closely related to the microbial community on C. demersum and E. crassipes. Furthermore, co-occurrence networks analysis (|r| > 0.7, p < 0.05) and functional prediction revealed more complex interactions among microbes on C. demersum than on E. crassipes and sediments, and those interactions include cross-feeding, parasitism, symbiosis, and predatism among organisms in biofilms. These results suggested that substrate-type and environmental factors were the strong driving forces of microbial diversity in epiphytic biofilms and surface sediments, thus shedding new insights into microbial community diversity in epiphytic biofilms and surface sediments and its ecological role in tropical lacustrine ecosystems.
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Affiliation(s)
- Benjamin Manirakiza
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, College of Environment, Hohai University, Nanjing 210098, China; University of Rwanda (UR), College of Science and Technology (CST), Department of Biology, P.O. Box 3900, Kigali, Rwanda
| | - Songhe Zhang
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, College of Environment, Hohai University, Nanjing 210098, China.
| | - Felix Gyawu Addo
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, College of Environment, Hohai University, Nanjing 210098, China
| | - Alain Isabwe
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Antoine Nsabimana
- University of Rwanda (UR), College of Science and Technology (CST), Department of Biology, P.O. Box 3900, Kigali, Rwanda
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Wang S, Sun P, Zhang G, Gray N, Dolfing J, Esquivel-Elizondo S, Peñuelas J, Wu Y. Contribution of periphytic biofilm of paddy soils to carbon dioxide fixation and methane emissions. Innovation (N Y) 2022; 3:100192. [PMID: 34950915 PMCID: PMC8672048 DOI: 10.1016/j.xinn.2021.100192] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 11/23/2021] [Indexed: 10/26/2022] Open
Abstract
Rice paddies are major contributors to anthropogenic greenhouse gas emissions via methane (CH4) flux. The accurate quantification of CH4 emissions from rice paddies remains problematic, in part due to uncertainties and omissions in the contribution of microbial aggregates on the soil surface to carbon fluxes. Herein, we comprehensively evaluated the contribution of one form of microbial aggregates, periphytic biofilm (PB), to carbon dioxide (CO2) and CH4 emissions from paddies distributed across three climatic zones, and quantified the pathways that drive net CH4 production as well as CO2 fixation. We found that PB accounted for 7.1%-38.5% of CH4 emissions and 7.2%-12.7% of CO2 fixation in the rice paddies. During their growth phase, PB fixed CO2 and increased the redox potential, which promoted aerobic CH4 oxidation. During the decay phase, PB degradation reduced redox potential and increased soil organic carbon availability, which promoted methanogenic microbial community growth and metabolism and increased CH4 emissions. Overall, PB acted as a biotic converter of atmospheric CO2 to CH4, and aggravated carbon emissions by up to 2,318 kg CO2 equiv ha-1 season-1. Our results provide proof-of-concept evidence for the discrimination of the contributions of surface microbial aggregates (i.e., PB) from soil microbes, and a profound foundation for the estimation and simulation of carbon fluxes in a potential novel approach to the mitigation of CH4 emissions by manipulating PB growth.
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Affiliation(s)
- Sichu Wang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China.,Zigui Three Gorges Reservoir Ecosystem, Observation and Research Station of Ministry of Water Resources of the People's Republic of China, Shuitianba Zigui, Yichang 443605, China.,College of Advanced Agricultural Science, University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Pengfei Sun
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China.,Zigui Three Gorges Reservoir Ecosystem, Observation and Research Station of Ministry of Water Resources of the People's Republic of China, Shuitianba Zigui, Yichang 443605, China
| | - Guangbin Zhang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China
| | - Neil Gray
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Jan Dolfing
- Faculty of Energy and Environment, Northumbria University, Newcastle upon Tyne NE1 8QH, UK
| | - Sofia Esquivel-Elizondo
- Department of Microbiome Science, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, 72076 Tübingen, Germany
| | - Josep Peñuelas
- Consejo Superior de Investigaciones Científicas (CSIC), Global Ecology Unit, Centre for Ecological Research and Forestry Applications (CREAF)-CSIC-Universitat Autonoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Catalonia, Spain
| | - Yonghong Wu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China.,Zigui Three Gorges Reservoir Ecosystem, Observation and Research Station of Ministry of Water Resources of the People's Republic of China, Shuitianba Zigui, Yichang 443605, China
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Acosta K, Appenroth KJ, Borisjuk L, Edelman M, Heinig U, Jansen MAK, Oyama T, Pasaribu B, Schubert I, Sorrels S, Sree KS, Xu S, Michael TP, Lam E. Return of the Lemnaceae: duckweed as a model plant system in the genomics and postgenomics era. THE PLANT CELL 2021; 33:3207-3234. [PMID: 34273173 PMCID: PMC8505876 DOI: 10.1093/plcell/koab189] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 06/18/2021] [Indexed: 05/05/2023]
Abstract
The aquatic Lemnaceae family, commonly called duckweed, comprises some of the smallest and fastest growing angiosperms known on Earth. Their tiny size, rapid growth by clonal propagation, and facile uptake of labeled compounds from the media were attractive features that made them a well-known model for plant biology from 1950 to 1990. Interest in duckweed has steadily regained momentum over the past decade, driven in part by the growing need to identify alternative plants from traditional agricultural crops that can help tackle urgent societal challenges, such as climate change and rapid population expansion. Propelled by rapid advances in genomic technologies, recent studies with duckweed again highlight the potential of these small plants to enable discoveries in diverse fields from ecology to chronobiology. Building on established community resources, duckweed is reemerging as a platform to study plant processes at the systems level and to translate knowledge gained for field deployment to address some of society's pressing needs. This review details the anatomy, development, physiology, and molecular characteristics of the Lemnaceae to introduce them to the broader plant research community. We highlight recent research enabled by Lemnaceae to demonstrate how these plants can be used for quantitative studies of complex processes and for revealing potentially novel strategies in plant defense and genome maintenance.
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Affiliation(s)
- Kenneth Acosta
- Department of Plant Biology, Rutgers the State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Klaus J Appenroth
- Plant Physiology, Matthias Schleiden Institute, University of Jena, Jena 07737, Germany
| | - Ljudmilla Borisjuk
- The Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben D-06466, Germany
| | - Marvin Edelman
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Uwe Heinig
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Marcel A K Jansen
- School of Biological, Earth and Environmental Sciences, Environmental Research Institute, University College Cork, Cork T23 TK30, Ireland
| | - Tokitaka Oyama
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Buntora Pasaribu
- Department of Plant Biology, Rutgers the State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Ingo Schubert
- The Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben D-06466, Germany
| | - Shawn Sorrels
- Department of Plant Biology, Rutgers the State University of New Jersey, New Brunswick, NJ 08901, USA
| | - K Sowjanya Sree
- Department of Environmental Science, Central University of Kerala, Periye 671320, India
| | - Shuqing Xu
- Institute for Evolution and Biodiversity, University of Münster, Münster 48149, Germany
| | | | - Eric Lam
- Author for correspondence: (E.L.), (T.P.M.)
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Zhang Y, Huang M, Zheng F, Guo S, Song X, Liu S, Li S, Zou J. Decreased Methane Emissions Associated with Methanogenic and Methanotrophic Communities in a Pig Manure Windrow Composting System under Calcium Superphosphate Amendment. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:6244. [PMID: 34207733 PMCID: PMC8296093 DOI: 10.3390/ijerph18126244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 06/01/2021] [Accepted: 06/02/2021] [Indexed: 11/18/2022]
Abstract
With the rapid growth of livestock breeding, manure composting has evolved to be an important source of atmospheric methane (CH4) which accelerates global warming. Calcium superphosphate (CaSSP), as a commonly used fertilizer, was proposed to be effective in reducing CH4 emissions from manure composting, but the intrinsic biological mechanism remains unknown. Methanogens and methanotrophs both play a key role in mediating CH4 fluxes, therefore we hypothesized that the CaSSP-mediated reduction in CH4 emissions was attributed to the shift of methanogens and methanotrophs, which was regulated by physicochemical parameter changes. To test this hypothesis, a 60-day pig manure windrow composting experiment was conducted to investigate the response of CH4 emissions to CaSSP amendment, with a close linkage to methanogenic and methanotrophic communities. Results showed that CaSSP amendment significantly reduced CH4 emissions by 49.5% compared with the control over the whole composting period. The decreased mcrA gene (encodes the α-subunit of methyl-coenzyme M reductase) abundance in response to CaSSP amendment suggested that the CH4 emissions were reduced primarily due to the suppressed microbial CH4 production. Illumina MiSeq sequencing analysis showed that the overall distribution pattern of methanogenic and methanotrophic communities were significantly affected by CaSSP amendment. Particularly, the relative abundance of Methanosarcina that is known to be a dominant group for CH4 production, significantly decreased by up to 25.3% accompanied with CaSSP addition. Only Type I methanotrophs was detected in our study and Methylocaldum was the dominant methanotrophs in this composting system; in detail, CaSSP amendment increased the relative abundance of OTUs belong to Methylocaldum and Methylobacter. Moreover, the increased SO42- concentration and decreased pH acted as two key factors influencing the methanogenic and methanotrophic composition, with the former has a negative effect on methanogenesis growth and can later promote CH4 oxidation at a low level. This study deepens our understanding of the interaction between abiotic factors, function microbiota and greenhouse gas (GHG) emissions, as well as provides implication for practically reducing composting GHG emissions.
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Affiliation(s)
- Yihe Zhang
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; (Y.Z.); (M.H.); (F.Z.); (S.G.); (S.L.); (J.Z.)
| | - Mengyuan Huang
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; (Y.Z.); (M.H.); (F.Z.); (S.G.); (S.L.); (J.Z.)
| | - Fengwei Zheng
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; (Y.Z.); (M.H.); (F.Z.); (S.G.); (S.L.); (J.Z.)
| | - Shumin Guo
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; (Y.Z.); (M.H.); (F.Z.); (S.G.); (S.L.); (J.Z.)
| | - Xiuchao Song
- Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China;
| | - Shuwei Liu
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; (Y.Z.); (M.H.); (F.Z.); (S.G.); (S.L.); (J.Z.)
- Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing 210095, China
| | - Shuqing Li
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; (Y.Z.); (M.H.); (F.Z.); (S.G.); (S.L.); (J.Z.)
- Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing 210095, China
| | - Jianwen Zou
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; (Y.Z.); (M.H.); (F.Z.); (S.G.); (S.L.); (J.Z.)
- Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing 210095, China
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10
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Tu Q, Lu Y, Zhao Y, Duan C, Huang J, Fang Y, Li B, Zhao H. Long-term effect of sediment on the performance of a pilot-scale duckweed-based waste stabilization pond. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 770:145216. [PMID: 33513505 DOI: 10.1016/j.scitotenv.2021.145216] [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: 09/27/2020] [Revised: 01/09/2021] [Accepted: 01/12/2021] [Indexed: 06/12/2023]
Abstract
Duckweed-based waste stabilization ponds (DWPs) have been widely used in wastewater treatment. However, the effects of sediment, an essential component of DWPs, on their performance have rarely been studied. In this study, two pilot-scale DWPs (12 m2) with sediment (DPS) and without sediment (DP) were evaluated over more than 1 year to determine the effects of sediment on duckweed growth, wastewater treatment, and greenhouse gas (GHG) production and emission in DWPs. The results indicated that the annual average duckweed growth rate were comparable, but protein content, carbon (C) and nitrogen (N) recovery rates of duckweed were slightly higher in the DPS than in the DP. Meanwhile, the dissolved oxygen (DO) and oxidation reduction potential (ORP), removal efficiencies of COD, TP, TN, NH4+-N, and turbidity of pond water from the DPS were significantly lower than for DP. More importantly, the DPS had considerably higher CH4 production/emission and global warming potential (GWP) than the DP, even though more than 90% of CH4 released from the sediment was consumed during its passage through the water column and duckweed layer. Sediment increased the recoveries of C and N by 7.94% and 8.82%, respectively. Influencing degree for COD, TP, TN, NH4+-N and turbidity were -27.92%, -20.98%, -22.61%, -24.13% and -14.91%, respectively; for pond water DO and ORP, the values were - 35.68% and -44.59%, respectively; and for CO2, CH4 and N2O emission and "combined GWP", they were 21.66%, 271.67%, -8.47% and 178.02%, respectively. Thus, this study indicates that sediment formed in the DWPs has a multi-faced effect on the performance of a DWP. In particular, sediment has an unfavourable effect on the wastewater treatment and the GHGs mitigation, but a favourable effect on the protein content and the C and N recoveries in duckweed.
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Affiliation(s)
- Qi Tu
- School of Ecology and Environmental Science & Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, Yunnan University, Kunming 650091, China
| | - Yifeng Lu
- School of Ecology and Environmental Science & Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, Yunnan University, Kunming 650091, China
| | - Yonggui Zhao
- School of Ecology and Environmental Science & Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, Yunnan University, Kunming 650091, China.
| | - Changqun Duan
- School of Ecology and Environmental Science & Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, Yunnan University, Kunming 650091, China
| | - Jun Huang
- Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences (CAS), Chengdu 610041, China
| | - Yang Fang
- Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences (CAS), Chengdu 610041, China
| | - Bo Li
- College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China
| | - Hai Zhao
- Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences (CAS), Chengdu 610041, China.
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11
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Physiology of Methylotrophs Living in the Phyllosphere. Microorganisms 2021; 9:microorganisms9040809. [PMID: 33921272 PMCID: PMC8069551 DOI: 10.3390/microorganisms9040809] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/02/2021] [Accepted: 04/07/2021] [Indexed: 01/06/2023] Open
Abstract
Methanol is abundant in the phyllosphere, the surface of the above-ground parts of plants, and its concentration oscillates diurnally. The phyllosphere is one of the major habitats for a group of microorganisms, the so-called methylotrophs, that utilize one-carbon (C1) compounds, such as methanol and methane, as their sole source of carbon and energy. Among phyllospheric microorganisms, methanol-utilizing methylotrophic bacteria, known as pink-pigmented facultative methylotrophs (PPFMs), are the dominant colonizers of the phyllosphere, and some of them have recently been shown to have the ability to promote plant growth and increase crop yield. In addition to PPFMs, methanol-utilizing yeasts can proliferate and survive in the phyllosphere by using unique molecular and cellular mechanisms to adapt to the stressful phyllosphere environment. This review describes our current understanding of the physiology of methylotrophic bacteria and yeasts living in the phyllosphere where they are exposed to diurnal cycles of environmental conditions.
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12
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Valach AC, Kasak K, Hemes KS, Anthony TL, Dronova I, Taddeo S, Silver WL, Szutu D, Verfaillie J, Baldocchi DD. Productive wetlands restored for carbon sequestration quickly become net CO2 sinks with site-level factors driving uptake variability. PLoS One 2021; 16:e0248398. [PMID: 33765085 PMCID: PMC7993764 DOI: 10.1371/journal.pone.0248398] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 02/26/2021] [Indexed: 11/22/2022] Open
Abstract
Inundated wetlands can potentially sequester substantial amounts of soil carbon (C) over the long-term because of slow decomposition and high primary productivity, particularly in climates with long growing seasons. Restoring such wetlands may provide one of several effective negative emission technologies to remove atmospheric CO2 and mitigate climate change. However, there remains considerable uncertainty whether these heterogeneous ecotones are consistent net C sinks and to what degree restoration and management methods affect C sequestration. Since wetland C dynamics are largely driven by climate, it is difficult to draw comparisons across regions. With many restored wetlands having different functional outcomes, we need to better understand the importance of site-specific conditions and how they change over time. We report on 21 site-years of C fluxes using eddy covariance measurements from five restored fresh to brackish wetlands in a Mediterranean climate. The wetlands ranged from 3 to 23 years after restoration and showed that several factors related to restoration methods and site conditions altered the magnitude of C sequestration by affecting vegetation cover and structure. Vegetation established within two years of re-flooding but followed different trajectories depending on design aspects, such as bathymetry-determined water levels, planting methods, and soil nutrients. A minimum of 55% vegetation cover was needed to become a net C sink, which most wetlands achieved once vegetation was established. Established wetlands had a high C sequestration efficiency (i.e. the ratio of net to gross ecosystem productivity) comparable to upland ecosystems but varied between years undergoing boom-bust growth cycles and C uptake strength was susceptible to disturbance events. We highlight the large C sequestration potential of productive inundated marshes, aided by restoration design and management targeted to maximise vegetation extent and minimise disturbance. These findings have important implications for wetland restoration, policy, and management practitioners.
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Affiliation(s)
- Alex C. Valach
- Ecosystem Science Division, Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, United States of America
| | - Kuno Kasak
- Ecosystem Science Division, Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, United States of America
- Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia
| | - Kyle S. Hemes
- Ecosystem Science Division, Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, United States of America
- Woods Institute for the Environment, Stanford University, Stanford, CA, United States of America
| | - Tyler L. Anthony
- Ecosystem Science Division, Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, United States of America
| | - Iryna Dronova
- Ecosystem Science Division, Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, United States of America
- Department of Landscape Architecture and Environmental Planning, University of California, Berkeley, CA, United States of America
| | - Sophie Taddeo
- Department of Landscape Architecture and Environmental Planning, University of California, Berkeley, CA, United States of America
| | - Whendee L. Silver
- Ecosystem Science Division, Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, United States of America
| | - Daphne Szutu
- Ecosystem Science Division, Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, United States of America
| | - Joseph Verfaillie
- Ecosystem Science Division, Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, United States of America
| | - Dennis D. Baldocchi
- Ecosystem Science Division, Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, United States of America
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13
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Meruvu H, Wu H, Jiao Z, Wang L, Fei Q. From nature to nurture: Essence and methods to isolate robust methanotrophic bacteria. Synth Syst Biotechnol 2020; 5:173-178. [PMID: 32637670 PMCID: PMC7327766 DOI: 10.1016/j.synbio.2020.06.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/03/2020] [Accepted: 06/18/2020] [Indexed: 02/07/2023] Open
Abstract
Methanotrophic bacteria are entities with innate biocatalytic potential to biofilter and oxidize methane into simpler compounds concomitantly conserving energy, which can contribute to copious industrial applications. The future and efficacy of such industrial applications relies upon acquiring and/or securing robust methanotrophs with taxonomic and phenotypic diversity. Despite several dramatic advances, isolation of robust methanotrophs is still a long-way challenging task with several lacunae to be filled in sequentially. Methanotrophs with high tolerance to methane can be isolated and cultivated by mimicking natural environs, and adopting strategies like adaptive metabolic evolution. This review summarizes existent and innovative methods for methanotrophic isolation and purification, and their respective applications. A comprehensive description of new insights shedding light upon how to isolate and concomitantly augment robust methanotrophic metabolism in an orchestrated fashion follows.
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Affiliation(s)
- Haritha Meruvu
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Hui Wu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Ziyue Jiao
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Liyan Wang
- Luoyang TMAXTREE Biotechnology Co., Ltd., Luoyang, China
| | - Qiang Fei
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, China
- Shaanxi Key Laboratory of Energy Chemical Process Intensification, Xi'an Jiaotong University, Xi'an, China
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14
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Ishizawa H, Kuroda M, Inoue D, Morikawa M, Ike M. Community dynamics of duckweed-associated bacteria upon inoculation of plant growth-promoting bacteria. FEMS Microbiol Ecol 2020; 96:5843272. [DOI: 10.1093/femsec/fiaa101] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 05/22/2020] [Indexed: 01/05/2023] Open
Abstract
ABSTRACT
Plant growth-promoting bacteria (PGPB) have recently been demonstrated as a promising agent to improve wastewater treatment and biomass production efficiency of duckweed hydrocultures. With a view to their reliable use in aqueous environments, this study analysed the plant colonization dynamics of PGPB and the ecological consequences for the entire duckweed-associated bacterial community. A PGPB strain, Aquitalea magnusonii H3, was inoculated to duckweed at different cell densities or timings in the presence of three environmental bacterial communities. The results showed that strain H3 improved duckweed growth by 11.7–32.1% in five out of nine experiments. Quantitative-PCR and amplicon sequencing analyses showed that strain H3 successfully colonized duckweed after 1 and 3 d of inoculation in all cultivation tests. However, it significantly decreased in number after 7 d, and similar bacterial communities were observed on duckweed regardless of H3 inoculation. Predicted metagenome analysis suggested that genes related to bacterial chemotactic motility and surface attachment systems are consistently enriched through community assembly on duckweed. Taken together, strain H3 dominantly colonized duckweed for a short period and improved duckweed growth. However, the inoculation of the PGPB did not have a lasting impact due to the strong resilience of the natural duckweed microbiome.
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Affiliation(s)
- Hidehiro Ishizawa
- Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University , 2-1 Suita, Osaka, Japan
| | - Masashi Kuroda
- Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University , 2-1 Suita, Osaka, Japan
| | - Daisuke Inoue
- Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University , 2-1 Suita, Osaka, Japan
| | - Masaaki Morikawa
- Division of Biosphere Science, Graduate School of Environmental Science, Hokkaido University, N10 W5 Sapporo, Hokkaido, Japan
| | - Michihiko Ike
- Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University , 2-1 Suita, Osaka, Japan
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15
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Faheem M, Shabbir S, Zhao J, Kerr PG, Sultana N, Jia Z. Enhanced Adsorptive Bioremediation of Heavy Metals (Cd 2+, Cr 6+, Pb 2+) by Methane-Oxidizing Epipelon. Microorganisms 2020; 8:microorganisms8040505. [PMID: 32244762 PMCID: PMC7232255 DOI: 10.3390/microorganisms8040505] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 03/28/2020] [Accepted: 03/30/2020] [Indexed: 12/01/2022] Open
Abstract
Cadmium (Cd), chromium (Cr) and lead (Pb) are heavy metals that have been classified as priority pollutants in aqueous environment while methane-oxidizing bacteria as a biofilter arguably consume up to 90% of the produced methane in the same aqueous environment before it escapes into the atmosphere. However, the underlying kinetics and active methane oxidizers are poorly understood for the hotspot of epipelon that provides a unique micro-ecosystem containing diversified guild of microorganisms including methane oxidizers for potential bioremediation of heavy metals. In the present study, the Pb2+, Cd2+and Cr6+ bioremediation potential of epipelon biofilm was assessed under both high (120,000 ppm) and near-atmospheric (6 ppm) methane concentrations. Epipelon biofilm demonstrated a high methane oxidation activity following microcosm incubation amended with a high concentration of methane, accompanied by the complete removal of 50 mg L−1 Pb2+ and 50 mg L−1 Cd2+ (14 days) and partial (20%) removal of 50 mg L−1 Cr6+ after 20 days. High methane dose stimulated a faster (144 h earlier) heavy metal removal rate compared to near-atmospheric methane concentrations. DNA-based stable isotope probing (DNA-SIP) following 13CH4 microcosm incubation revealed the growth and activity of different phylotypes of methanotrophs during the methane oxidation and heavy metal removal process. High throughput sequencing of 13C-labelled particulate methane monooxygenase gene pmoA and 16S rRNA genes revealed that the prevalent active methane oxidizers were type I affiliated methanotrophs, i.e., Methylobacter. Type II methanotrophs including Methylosinus and Methylocystis were also labeled only under high methane concentrations. These results suggest that epipelon biofilm can serve as an important micro-environment to alleviate both methane emission and the heavy metal contamination in aqueous ecosystems with constant high methane fluxes.
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Affiliation(s)
- Muhammad Faheem
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; (M.F.); (J.Z.); (N.S.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sadaf Shabbir
- College of Environment, Hohai University, Nanjing 210098, China;
| | - Jun Zhao
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; (M.F.); (J.Z.); (N.S.)
| | - Philip G. Kerr
- School of Biomedical Science, Charles Sturt University, Wagga Wagga, NSW 2678, Australia;
| | - Nasrin Sultana
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; (M.F.); (J.Z.); (N.S.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhongjun Jia
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; (M.F.); (J.Z.); (N.S.)
- Correspondence:
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