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Schiml VC, Walter JM, Hagen LH, Varnai A, Bergaust LL, De Leon AVP, Elsgaard L, Bakken LR, Arntzen MØ. Microbial consortia driving (ligno)cellulose transformation in agricultural woodchip bioreactors. Appl Environ Microbiol 2024; 90:e0174224. [PMID: 39526802 DOI: 10.1128/aem.01742-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2024] [Accepted: 10/08/2024] [Indexed: 11/16/2024] Open
Abstract
Freshwater ecosystems can be largely affected by neighboring agriculture fields where potential fertilizer nitrate run-off may leach into surrounding water bodies. To counteract this eutrophic driver, farmers in certain areas are utilizing denitrifying woodchip bioreactors (WBRs) in which a consortium of microorganisms convert the nitrate into nitrogen gases in anoxia, fueled by the degradation of lignocellulose. Polysaccharide-degrading strategies have been well described for various aerobic and anaerobic systems, including the use of carbohydrate-active enzymes, utilization of lytic polysaccharide monooxygenases (LPMOs) and other redox enzymes, as well as the use of cellulosomes and polysaccharide utilization loci (PULs). However, for denitrifying microorganisms, the lignocellulose-degrading strategies remain largely unknown. Here, we have applied a combination of enrichment techniques, gas measurements, multi-omics approaches, and amplicon sequencing of fungal ITS and procaryotic 16S rRNA genes to identify microbial drivers for lignocellulose transformation in woodchip bioreactors and their active enzymes. Our findings highlight a microbial community enriched for (ligno)cellulose-degrading denitrifiers with key players from the taxa Giesbergeria, Cellulomonas, Azonexus, and UBA5070 (Fibrobacterota). A wide substrate specificity is observed among the many expressed carbohydrate-active enzymes (CAZymes) including PULs from Bacteroidetes. This suggests a broad degradation of lignocellulose subfractions, including enzymes with auxiliary activities whose functionality is still puzzling under strict anaerobic conditions. IMPORTANCE Freshwater ecosystems face significant threats from agricultural runoff, which can lead to eutrophication and subsequent degradation of water quality. One solution to mitigate this issue is using denitrifying woodchip bioreactors (WBRs), where microorganisms convert nitrate into nitrogen gases utilizing lignocellulose as a carbon source. Despite the well-documented polysaccharide-degrading strategies in various systems, the mechanisms employed by denitrifying microorganisms in WBRs remain largely unexplored. This study fills a critical knowledge gap by revealing the degrading strategies of denitrifying microbial communities in WBRs. By integrating state-of-the-art techniques, we have identified key microbial drivers including Giesbergeria, Cellulomonas, Azonexus, and UBA5070 (Fibrobacterota) playing significant roles in lignocellulose transformation and showcasing a broad substrate specificity and complex metabolic capability. Our findings advance the understanding of microbial ecology in WBRs and by revealing the enzymatic activities, this research may inform efforts to improve water quality, protect aquatic ecosystems, and reduce greenhouse gas emissions from WBRs.
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Affiliation(s)
- Valerie C Schiml
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Juline M Walter
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Live H Hagen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Aniko Varnai
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Linda L Bergaust
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Arturo Vera Ponce De Leon
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
- Faculty of Biosciences, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Lars Elsgaard
- Department of Agroecology, Aarhus University, Tjele, Denmark
| | - Lars R Bakken
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Magnus Ø Arntzen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
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Gan X, Hu H, Fu Q, Zhu J. Nitrate reduction coupling with As(III) oxidation in neutral As-contaminated paddy soil preserves nitrogen, reduces N 2O emissions and alleviates As toxicity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169360. [PMID: 38104836 DOI: 10.1016/j.scitotenv.2023.169360] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 11/29/2023] [Accepted: 12/11/2023] [Indexed: 12/19/2023]
Abstract
In arsenic (As)-contaminated paddy soil, microbial-driven nitrate (NO3-) reduction coupled with arsenite (As(III)) oxidation can reduce As toxicity, but the whereabouts of NO3- remain unclear. In this study, the experiments were established using selective streptomycin (STP) and cyclohexylamine to inhibit bacterial and fungal functional responses, respectively, and metagenomic sequencing techniques were used to explain the biological mechanisms of NO3- reduction coupled with As(III) oxidation in neutral As-contaminated paddy soil. The results indicated that fungal denitrification resulted in stronger nitrous oxide (N2O) emissions (321.6 μg kg-1) than bacterial denitrification (175.9 μg kg-1) in neutral As-contaminated paddy soil, but NO3- reduction coupled with As(III) oxidation reduced the N2O emissions. Only adding STP led to ammonium (NH4+) generation (17.7 mg kg-1), and simultaneously more NH4+ appeared in NO3- reduction coupled with As(III) oxidation; this may be because it improved the electron transfer efficiency by 18.2 %. Achromobacter was involved in denitrification coupled with As(III) oxidation. Burkholderiales was responsible for NO3- reduction to NH4+ coupled with As(III) oxidation. This study provided a theoretical basis for NO3- reduction coupled with As(III) oxidation reducing N2O emissions, promoting the reduction of NO3- to NH4+, and reducing As toxicity in paddy soil.
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Affiliation(s)
- Xuelian Gan
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural Affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Hongqing Hu
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural Affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Qingling Fu
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural Affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
| | - Jun Zhu
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural Affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
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Xu MJ, Cui YW, Huang MQ, Sui Y. Simultaneous inorganic nitrogen and phosphate removal by aerobic-heterotrophic fungus Fusarium keratoplasticum FSP1: Performance, pathway and application. BIORESOURCE TECHNOLOGY 2024; 393:130141. [PMID: 38040316 DOI: 10.1016/j.biortech.2023.130141] [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: 09/26/2023] [Revised: 11/15/2023] [Accepted: 11/28/2023] [Indexed: 12/03/2023]
Abstract
Fungi with multiple contaminant removal function have rarely been studied. Here, a novel fungal strain Fusarium keratoplasticum FSP1, which was isolated from halophilic granular sludge, is reported for first time to perform simultaneous nitrogen and phosphate removal. The strain showed wide adaptability under C/N ratios of 30-35, salinities of 0 %-3 % (m/v), and pH of 7.5-9.5. The maximum removal rates of ammonium, nitrate and nitrite were 4.43, 4.01 and 2.97 mg N/L/h. The nitrogen balance, enzyme activity and substrate conversion experiments demonstrated a single strain FSP1 can assimilate inorganic nitrogen and convert inorganic nitrogen to gaseous nitrogen through heterotrophic nitrification or aerobic denitrification. About 39 %-42 % of the degraded phosphorus was in the extracellular polymeric substances (EPS). Orthophosphate was the main phosphorus species in the cell, whereas phosphate monoester and diester were in the EPS. The novel strain FSP1 is a potential candidate for wastewater treatment.
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Affiliation(s)
- Meng-Jiao Xu
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China
| | - You-Wei Cui
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China.
| | - Mei-Qi Huang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China
| | - Yuan Sui
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China
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Jiang JP, Leng S, Liao YF, Liu X, Li DX, Chu C, Yu XY, Liu CH. The potential role of subseafloor fungi in driving the biogeochemical cycle of nitrogen under anaerobic conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 897:165374. [PMID: 37422230 DOI: 10.1016/j.scitotenv.2023.165374] [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: 04/29/2023] [Revised: 07/01/2023] [Accepted: 07/05/2023] [Indexed: 07/10/2023]
Abstract
Fungi represent the dominant eukaryotic group of organisms in anoxic marine sedimentary ecosystems, ranging from a few centimeters to ~ 2.5 km below seafloor. However, little is known about how fungi can colonize anaerobic subseafloor environments for tens of millions of years and whether they play a role in elemental biogeochemical cycles. Based on metabolite detection, isotope tracer and gene analysis, we examined the anaerobic nitrogen conversion pathways of 19 fungal species (40 strains) isolated from1.3 to 2.5 km coal-bearing sediments below seafloor. Our results show for the first time that almost all fungi possess anaerobic denitrification, dissimilatory nitrate reduction to ammonium (DNRA), and nitrification pathways, but not anaerobic ammonium oxidation (anammox). Moreover, the distribution of fungi with different nitrogen-conversion abilities in subseafloor sediments was mainly determined by in situ temperature, CaCO3, and inorganic carbon contents. These findings suggest that fungi have multiple nitrogen transformation processes to cope with their requirements for a variety of nitrogen sources in nutrient deficient anaerobic subseafloor sedimentary environments.
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Affiliation(s)
- Jun-Peng Jiang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Shuang Leng
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Yi-Fan Liao
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Xuan Liu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Dong-Xu Li
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Chen Chu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Xiang-Yang Yu
- Jiangsu Key Laboratory for Food Quality, Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
| | - Chang-Hong Liu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China.
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Lee S, Cho M, Sadowsky MJ, Jang J. Denitrifying Woodchip Bioreactors: A Microbial Solution for Nitrate in Agricultural Wastewater-A Review. J Microbiol 2023; 61:791-805. [PMID: 37594681 DOI: 10.1007/s12275-023-00067-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/04/2023] [Accepted: 07/05/2023] [Indexed: 08/19/2023]
Abstract
Nitrate (NO3-) is highly water-soluble and considered to be the main nitrogen pollutants leached from agricultural soils. Its presence in aquatic ecosystems is reported to cause various environmental and public health problems. Bioreactors containing microbes capable of transforming NO3- have been proposed as a means to remediate contaminated waters. Woodchip bioreactors (WBRs) are continuous flow, reactor systems located below or above ground. Below ground systems are comprised of a trench filled with woodchips, or other support matrices. The nitrate present in agricultural drainage wastewater passing through the bioreactor is converted to harmless dinitrogen gas (N2) via the action of several bacteria species. The WBR has been suggested as one of the most cost-effective NO3--removing strategy among several edge-of-field practices, and has been shown to successfully remove NO3- in several field studies. NO3- removal in the WBR primarily occurs via the activity of denitrifying microorganisms via enzymatic reactions sequentially reducing NO3- to N2. While previous woodchip bioreactor studies have focused extensively on its engineering and hydrological aspects, relatively fewer studies have dealt with the microorganisms playing key roles in the technology. This review discusses NO3- pollution cases originating from intensive farming practices and N-cycling microbial metabolisms which is one biological solution to remove NO3- from agricultural wastewater. Moreover, here we review the current knowledge on the physicochemical and operational factors affecting microbial metabolisms resulting in removal of NO3- in WBR, and perspectives to enhance WBR performance in the future.
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Affiliation(s)
- Sua Lee
- Division of Biotechnology and Advanced Institute of Environment and Bioscience, Jeonbuk National University, Iksan, Jeonbuk, 54596, Republic of Korea
| | - Min Cho
- Division of Biotechnology and Advanced Institute of Environment and Bioscience, Jeonbuk National University, Iksan, Jeonbuk, 54596, Republic of Korea
| | - Michael J Sadowsky
- BioTechnology Institute, Department of Soil, Water and Climate, and Department of Microbial and Plant Biology, University of Minnesota, St. Paul, MN, 55108, USA
| | - Jeonghwan Jang
- Division of Biotechnology and Advanced Institute of Environment and Bioscience, Jeonbuk National University, Iksan, Jeonbuk, 54596, Republic of Korea.
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6
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Tabraiz S, Aiswarya NM, Taneja H, Narayanan RA, Ahmed A. Biofilm-based simultaneous nitrification, denitrification, and phosphorous uptake in wastewater by Neurospora discreta. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 324:116363. [PMID: 36208511 DOI: 10.1016/j.jenvman.2022.116363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 09/14/2022] [Accepted: 09/22/2022] [Indexed: 06/16/2023]
Abstract
Biological removal of nitrogen and phosphorous from wastewater conventionally involves multiple processing steps to satisfy the differing oxygen requirements of the microbial species involved. In this work, simultaneous nitrification, denitrification, and phosphorous removal from synthetic wastewater were achieved by the fungus Neurospora discreta in a single-step, biofilm-based, aerobic process. The concentrations of carbon, nitrogen, and phosphorous in the synthetic wastewater were systematically varied to investigate their effects on nutrient removal rates and biofilm properties. Biofilm growth was significantly (p < 0.05) affected by carbon and nitrogen, but not by phosphorous concentration. Scanning electron microscopy revealed the effects of nutrients on biofilm microstructure, which in turn correlated with nutrient removal efficiencies. The carbohydrate and protein content in the biofilm matrix decreased with increasing carbon and nitrogen concentrations but increased with increasing phosphorous concentration in the wastewater. High removal efficiencies of carbon (96%), ammonium (86%), nitrate (100%), and phosphorus (82%) were achieved under varying nutrient conditions. Interestingly, decreasing the phosphorus concentration increased the nitrification and denitrification rates, and decreasing the nitrogen concentration increased the phosphorus removal rates significantly (p < 0.05). Correlations between biofilm properties and nutrient removal rates were also evaluated in this study.
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Affiliation(s)
- Shamas Tabraiz
- Section of Natural and Applied Sciences, Canterbury Christ Church University, UK
| | - N M Aiswarya
- Department of Physics, Birla Institute of Technology and Science Pilani, Hyderabad Campus, India
| | - Himani Taneja
- Section of Natural and Applied Sciences, Canterbury Christ Church University, UK
| | - R Aravinda Narayanan
- Department of Physics, Birla Institute of Technology and Science Pilani, Hyderabad Campus, India
| | - Asma Ahmed
- Section of Natural and Applied Sciences, Canterbury Christ Church University, UK.
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Chen Z, Fei YH, Liu WS, Ding K, Lu J, Cai X, Cui T, Tang YT, Wang S, Chao Y, Qiu R. Untangling microbial diversity and assembly patterns in rare earth element mine drainage in South China. WATER RESEARCH 2022; 225:119172. [PMID: 36191530 DOI: 10.1016/j.watres.2022.119172] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 09/23/2022] [Accepted: 09/24/2022] [Indexed: 06/16/2023]
Abstract
Ion-adsorption rare earth element (REE) deposits are the main reservoirs of REEs worldwide, and are widely exploited in South China. Microbial diversity is essential for maintaining the performance and function of mining ecosystems. Investigating the ecological patterns underlying the REE mine microbiome is essential to understand ecosystem responses to environmental changes and to improve the bioremediation of mining areas. We applied 16S rRNA and ITS gene sequence analyses to investigate the composition characteristics of prokaryotic (bacteria, archaea) and fungal communities in a river impacted by REE acid mine drainage (REE-AMD). The river formed a unique micro-ecosystem, including the main prokaryotic taxa of Proteobacteria, Acidobacteria, Crenarchaeota, and Euryarchaeota, as well as the main fungal taxa of Ascomycota, Basidiomycota, and Chytridiomycota. Analysis of microbial diversity showed that, unlike prokaryotic communities that responded drastically to pollution disturbances, fungal communities were less affected by REE-AMD, but fluctuated significantly in different seasons. Ecological network analysis revealed that fungal communities have lower connectivity and centrality, and higher modularity than prokaryotic networks, indicating that fungal communities have more stable network structures. The introduction of REE-AMD mainly reduced the complexity of the community network and the number of keystone species, while the proportion of negative prokaryotic-fungal associations in the network increased. Ecological process analysis revealed that, compared to the importance of environmental selection for prokaryotes, stochastic processes might have contributed primarily to fungal communities in REE mining areas. These findings confirm that the different assembly mechanisms of prokaryotic and fungal communities are key to the differences in their responses to environmental perturbations. The findings also provide the first insights into microbiota assembly patterns in REE-AMD and important ecological knowledge for the formation and development of microbial communities in REE mining areas.
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Affiliation(s)
- Ziwu Chen
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China; National-level Nanchang Economic and Technical Development Zone, Nanchang 330000, China
| | - Ying-Heng Fei
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Wen-Shen Liu
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Provincial Engineering Research Center for Heavy Metal Contaminated Soil Remediation, Sun Yat-sen University, Guangzhou 510275, China
| | - Kengbo Ding
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Provincial Engineering Research Center for Heavy Metal Contaminated Soil Remediation, Sun Yat-sen University, Guangzhou 510275, China
| | - Jianan Lu
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Xuan Cai
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Tuantuan Cui
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Ye-Tao Tang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Provincial Engineering Research Center for Heavy Metal Contaminated Soil Remediation, Sun Yat-sen University, Guangzhou 510275, China
| | - Shizhong Wang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Provincial Engineering Research Center for Heavy Metal Contaminated Soil Remediation, Sun Yat-sen University, Guangzhou 510275, China
| | - Yuanqing Chao
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Provincial Engineering Research Center for Heavy Metal Contaminated Soil Remediation, Sun Yat-sen University, Guangzhou 510275, China.
| | - Rongliang Qiu
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Provincial Engineering Research Center for Heavy Metal Contaminated Soil Remediation, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Laboratory for Lingnan Modern Agriculture, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China
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Identification of Exoenzymes Secreted by Entomopathogenic Fungus Beauveria pseudobassiana RGM 2184 and Their Effect on the Degradation of Cocoons and Pupae of Quarantine Pest Lobesia botrana. J Fungi (Basel) 2022; 8:jof8101083. [PMID: 36294649 PMCID: PMC9605004 DOI: 10.3390/jof8101083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 09/29/2022] [Accepted: 10/06/2022] [Indexed: 11/07/2022] Open
Abstract
Beauveria pseudobassiana RGM 2184 has shown 80% maximum efficacy against the pest Lobesia botrana in the autumn and winter seasons. This suggests that the strain possesses an interesting battery of enzymes that are cold-adapted to penetrate the thick and hydrophobic cocoon of L. botrana. In this study, screening of the proteolytic, lipolytic, and chitinolytic activity of enzyme extracts secreted by the RGM 2184 strain was carried out in various culture media. The enzyme extracts with the highest activity were subjected to zymography and mass spectrometry. These analyses allowed the identification of two proteases, two lipases, and three chitinases. Comparative analysis indicated that the degree of similarity between these enzymes was substantially reduced when the highest degree of taxonomic relatedness between RGM 2184 and the entomopathogenic fungus strain was at the family level. These results suggest that there is a wide variety of exoenzymes in entomopathogenic fungi species belonging to the order Hypocreales. On the other hand, exoenzyme extract exposure of cocoons and pupae of L. botrana provoked damage at 10 °C. Additionally, an analysis of the amino acid composition of the RGM 2184 exoenzyme grouped them close to the cold-adapted protein cluster. These results support the use of this strain to control pests in autumn and winter. Additionally, these antecedents can form a scaffold for the future characterization of these exoenzymes along with the optimization of the strain’s biocontrol ability by overexpressing them.
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Salo M, Bomberg M. Sulfate-reducing bioreactors subjected to high sulfate loading rate or acidity: variations in microbial consortia. AMB Express 2022; 12:95. [PMID: 35841424 PMCID: PMC9288570 DOI: 10.1186/s13568-022-01438-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 07/06/2022] [Indexed: 12/01/2022] Open
Abstract
Sulfate-reducing bioreactors are used in e.g. the mining industry to remove sulfate and harmful metals from process waters. These bioreactors are expected to be run for extended periods of time and may experience variations in the influent quality, such as increasing sulfate loading rate and decrease in pH, while being expected to function optimally. In this study we followed the sulfate removal rate and variation in microbial communities over a period of up to 333 days in three different up-flow anaerobic sludge blanket (UASB) bioreactors being submitted to increasing sulfate loading rate or decreasing pH. Sodium lactate was used as the sole carbon source and electron donor. All three bioreactors contained highly diverse microbial communities containing archaea, fungi and bacteria. Sulfurospirillum and Desulfovibrio were the most prominent bacterial genera detected in the bioreactors receiving the highest sulfate loading rates, and the greatest relative abundance of methanogenic archaea and the fungal genus Cadophora coincided with the highest sulfate reduction rates. In contrast, Sulfuricurvum was dominant in the bioreactor receiving influent with alternating pH, but its relative abundance receded in response to low pH of the influent. All bioreactors showed excellent sulfate removal even under extreme conditions in addition to unique responses in the microbial communities under changing operational conditions. This shows that a high diversity in the microbial consortia in the bioreactors could make the sulfate removal process less sensitive to changing operational conditions, such as variations in influent sulfate loading rate and pH. Influents with high sulfate loading rate or low pH were successfully treated. Microbial consortia showed versatility and adaption to changing operation. Unknown interactions among microbial groups makes interpretation challenging.
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Affiliation(s)
- Marja Salo
- VTT Technical Research Centre of Finland Ltd, P.O.Box 1000, 02044, Espoo, Finland.
| | - Malin Bomberg
- VTT Technical Research Centre of Finland Ltd, P.O.Box 1000, 02044, Espoo, Finland
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10
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Genome Sequence of Linnemannia hyalina Strain SCG-10, a Cold-Adapted and Nitrate-Reducing Fungus Isolated from Cornfield Soil in Minnesota, USA. Microbiol Resour Announc 2021; 10:e0069221. [PMID: 34528820 PMCID: PMC8444964 DOI: 10.1128/mra.00692-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report here the genome sequence of Linnemannia hyalina strain SCG-10, a cold-adapted and nitrate-reducing fungus isolated from soil. The genome of strain SCG-10 (51.6 Mbp) contained 12,693 protein-coding sequences.
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11
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Jéglot A, Audet J, Sørensen SR, Schnorr K, Plauborg F, Elsgaard L. Microbiome Structure and Function in Woodchip Bioreactors for Nitrate Removal in Agricultural Drainage Water. Front Microbiol 2021; 12:678448. [PMID: 34421841 PMCID: PMC8377596 DOI: 10.3389/fmicb.2021.678448] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 07/21/2021] [Indexed: 11/13/2022] Open
Abstract
Woodchip bioreactors are increasingly used to remove nitrate (NO3–) from agricultural drainage water in order to protect aquatic ecosystems from excess nitrogen. Nitrate removal in woodchip bioreactors is based on microbial processes, but the microbiomes and their role in bioreactor efficiency are generally poorly characterized. Using metagenomic analyses, we characterized the microbiomes from 3 full-scale bioreactors in Denmark, which had been operating for 4–7 years. The microbiomes were dominated by Proteobacteria and especially the genus Pseudomonas, which is consistent with heterotrophic denitrification as the main pathway of NO3– reduction. This was supported by functional gene analyses, showing the presence of the full suite of denitrification genes from NO3– reductases to nitrous oxide reductases. Genes encoding for dissimilatory NO3– reduction to ammonium were found only in minor proportions. In addition to NO3– reducers, the bioreactors harbored distinct functional groups, such as lignocellulose degrading fungi and bacteria, dissimilatory sulfate reducers and methanogens. Further, all bioreactors harbored genera of heterotrophic iron reducers and anaerobic iron oxidizers (Acidovorax) indicating a potential for iron-mediated denitrification. Ecological indices of species diversity showed high similarity between the bioreactors and between the different positions along the flow path, indicating that the woodchip resource niche was important in shaping the microbiome. This trait may be favorable for the development of common microbiological strategies to increase the NO3– removal from agricultural drainage water.
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Affiliation(s)
- Arnaud Jéglot
- Department of Agroecology, Aarhus University, Aarhus, Denmark.,Centre for Water Technology (WATEC), Aarhus University, Aarhus, Denmark
| | - Joachim Audet
- Centre for Water Technology (WATEC), Aarhus University, Aarhus, Denmark.,Department of Bioscience, Aarhus University, Silkeborg, Denmark
| | | | | | - Finn Plauborg
- Department of Agroecology, Aarhus University, Aarhus, Denmark.,Centre for Water Technology (WATEC), Aarhus University, Aarhus, Denmark
| | - Lars Elsgaard
- Department of Agroecology, Aarhus University, Aarhus, Denmark
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