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You X, Wang S, Chen J. Magnetic biochar accelerates microbial succession and enhances assimilatory nitrate reduction during pig manure composting. Environ Int 2024; 184:108469. [PMID: 38324928 DOI: 10.1016/j.envint.2024.108469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 01/30/2024] [Accepted: 01/30/2024] [Indexed: 02/09/2024]
Abstract
Biochar promotes microbial metabolic activities and reduces N2O on aerobic composting. However, the effects of magnetic biochar (MBC) on the microbial succession and N2O emissions during pig manure composting remain unclear. Herein, a 42-day composting experiment was conducted with five treatment regimes: pig manure without biochar (CK), 5 % pig manure-based biochar (5 % PBC), 2 % MBC (2 % MBC), 5 % MBC (5 % MBC) and 7.5 % MBC (7.5 % MBC)), to clarify the variation in functional microorganisms and genes associated with nitrogen and direct interspecies electron transfer via metagenomics. Fourier-transform infrared spectroscopy showed that MBC possessed more stable aromatic structures than pig manure-based biochar (PBC), indicating its greater potential for nitrous oxide reduction. MBC treatments were more effective in composting organic matter and improving the carbon/nitrogen ratio than PBC. The microbial composition during composting varied significantly, with the dominant phyla shifting from Firmicutes to Proteobacteria, Actinobacteria, and Bacteroidota. Network and hierarchical clustering analyses showed that the MBC treatment enhanced the interactions of dominant microbes (Proteobacteria and Bacteroidota) and accelerated the composting process. The biochar addition accelerated assimilatory nitrate reduction and slowed dissimilatory nitrate reduction and denitrification. The Mantel test demonstrated that magnetic biochar potentially helped regulate composting nutrients and affected functional nitrogen genes. These findings shed light on the role of MBC in mitigating greenhouse gas emissions during aerobic composting.
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Affiliation(s)
- Xinxin You
- Institute of Eco-environmental Sciences, Wenzhou Academy of Agricultural Sciences, Wenzhou 325006, PR China; Southern Zhejiang Key Laboratory of Crop Breeding, Wenzhou Academy of Agricultural Sciences, Wenzhou 325006, PR China; The State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, PR China.
| | - Sheng Wang
- Institute of Eco-environmental Sciences, Wenzhou Academy of Agricultural Sciences, Wenzhou 325006, PR China
| | - Junhui Chen
- The State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, PR China
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Wang X, Xiang B, Li J, Zhang M, Frostegard A, Bakken L, Zhang X. Using adaptive and aggressive N 2O-reducing bacteria to augment digestate fertilizer for mitigating N 2O emissions from agricultural soils. Sci Total Environ 2023; 903:166284. [PMID: 37586512 DOI: 10.1016/j.scitotenv.2023.166284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 08/09/2023] [Accepted: 08/11/2023] [Indexed: 08/18/2023]
Abstract
Nitrous oxide (N2O) emitted from agricultural soils destroys stratospheric ozone and contributes to global warming. A promising approach to reduce emissions is fertilizing the soil using organic wastes augmented by non-denitrifying N2O-reducing bacteria (NNRB). To realize this potential, we need a suite of NNRB strains that fulfill several criteria: efficient reduction of N2O, ability to grow in organic waste, and ability to survive in farmland soil. In this study, we enriched such organisms by sequential anaerobic batch incubations with N2O and reciprocating inoculation between the sterilized substrates of anaerobic manure digestate and soils. 16S rDNA amplicon sequencing and metagenomics analysis showed that a cluster of bacteria containing nosZ genes encoding N2O-reductase, was enriched during the incubation process. Strains of several dominant members were then isolated and characterized, and three of them were found to harbor the nosZ gene but none of the other denitrifying genes, thus qualifying as NNRB. The selected isolates were tested for their capacities to reduce N2O emissions from three different typical Chinese farmland soils. The results indicated the significant mitigation effect of these isolates, even in very acidic red soil. In conclusion, this study demonstrated a strategy to engineer the soil microbiome with promising NNRB with high adaptability to livestock manure digestate as well as different agricultural soils, which would be suitable for developing novel fertilizer for farmland application to efficiently mitigate the N2O emissions from agricultural soils.
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Affiliation(s)
- Xinhui Wang
- State Key Laboratory of Microbial Metabolism, and Joint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Baoyu Xiang
- State Key Laboratory of Microbial Metabolism, and Joint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ji Li
- State Key Laboratory of Microbial Metabolism, and Joint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Menghui Zhang
- State Key Laboratory of Microbial Metabolism, and Joint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Asa Frostegard
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Aas, Norway
| | - Lars Bakken
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Aas, Norway
| | - Xiaojun Zhang
- State Key Laboratory of Microbial Metabolism, and Joint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
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3
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Gao N, Yu X, Yang S, Li Q, Zhang H, Rajasekar A, Shen W, Senoo K. Mitigation of N2O emission from granular organic fertilizer with alkali- and salt-resistant plant growth-promoting rhizobacteria. J Appl Microbiol 2023; 134:lxad225. [PMID: 37777842 DOI: 10.1093/jambio/lxad225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 09/16/2023] [Accepted: 09/29/2023] [Indexed: 10/02/2023]
Abstract
AIM Organic fertilizer application significantly stimulates nitrous oxide (N2O) emissions from agricultural soils. Plant growth-promoting rhizobacteria (PGPR) strains are the core of bio-fertilizer or bio-organic fertilizer, while their beneficial effects are inhibited by environmental conditions, such as alkali and salt stress observed in organic manure or soil. This study aims to screen alkali- and salt-resistant PGPR that could mitigate N2O emission after applying strain-inoculated organic fertilizer. METHODS AND RESULTS Among the 29 candidate strains, 11 (7 Bacillus spp., 2 Achromobacter spp., 1 Paenibacillus sp., and 1 Pseudomonas sp.) significantly mitigated N2O emissions from the organic fertilizer after inoculation. Seven strains were alkali tolerant (pH 10) and five were salt tolerant (4% salinity) in pure culture. Seven strains were selected for further evaluation in two agricultural soils. Five of these seven strains could significantly decrease the cumulative N2O emissions from Anthrosol, while six could significantly decrease the cumulative N2O emissions from Cambisol after the inoculation into the granular organic fertilizer compared with the non-inoculated control. CONCLUSIONS Inoculating alkali- and salt-resistant PGPR into organic fertilizer can reduce N2O emissions from soils under microcosm conditions. Further studies are needed to investigate whether these strains will work under field conditions, under higher salinity, or at different soil pH.
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Affiliation(s)
- Nan Gao
- National Engineering Research Center for Biotechnology, School of Biological and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Xinchun Yu
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, and School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Siqi Yang
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, and School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Qing Li
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, and School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Huanhuan Zhang
- National Engineering Research Center for Biotechnology, School of Biological and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Adharsh Rajasekar
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, and School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Weishou Shen
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, and School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
- Institute of Soil Health and Climate-Smart Agriculture, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Keishi Senoo
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo 113-8657, Japan
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Subbarao PMV, D' Silva TC, Adlak K, Kumar S, Chandra R, Vijay VK. Anaerobic digestion as a sustainable technology for efficiently utilizing biomass in the context of carbon neutrality and circular economy. Environ Res 2023; 234:116286. [PMID: 37263473 DOI: 10.1016/j.envres.2023.116286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 05/28/2023] [Accepted: 05/29/2023] [Indexed: 06/03/2023]
Abstract
Carbon emissions and associated global warming have become a threat to the world, the major contributor being the extensive use of fossil fuels and uncontrolled generation of solid wastes. Energy generation from renewable energy sources is considered an alternative to achieving carbon neutrality. Anaerobic digestion (AD) is a sustainable technology that has been endorsed as a low-carbon technology complimenting both waste management and renewable energy sectors. The AD technology recovers the volatile matter from waste biomass as much as possible to produce biogas, thus reducing carbon emission as compared to open dumping or burning. However, there is a need of compilation of information on how each subsystem in AD contributes to the overall carbon neutrality of the entire system and chances of achieving a circular economy along with it. Therefore, this article aims to clarify the associated internal and external factors that determine the low carbon characteristic of anaerobic digestion technology. From this review, the potential of AD system for energy-atmosphere-agriculture nexus has been explored. Carbon emission mapping of the potential entities involved in AD were identified and perspective to life cycle assessment and future research direction has been pointed out. Climate change impact and acidification potential are the two entities that can influence the overall environmental sustainability of an AD system. It was recognized that each stage of AD system starting from substrate supply chain, biogas production, upgradation, utilization, and digestate application had a remarkable effect on the overall carbon emission potential based on its design, operation, and maintenance. Selection of suitable substrates and co-digesting them together for improved biogas production rate with high methane content and proper digestate post-processing and storage can vastly reduce the carbon emission potential of the AD technology. Further, a case scenario of India was assessed considering the utilization of major surplus biomass available through AD. Re-routing the three major substrates such as agricultural crop residues, animal wastes and organic fraction of municipal solid wastes through AD can reduce at least 3.5-3.8 kg CO2-eq per capita of annual carbon emission load in India. Furthermore, the pathways in which the policy and legislations over establishment of AD technology and how to explore linkages between achieving circular economy and low carbon economy for Indian scenario has been highlighted.
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Affiliation(s)
- Paruchuri M V Subbarao
- Department of Mechanical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India
| | - Tinku Casper D' Silva
- Centre for Rural Development and Technology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India
| | - Komalkant Adlak
- Centre for Rural Development and Technology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India
| | - Subodh Kumar
- Centre for Rural Development and Technology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India
| | - Ram Chandra
- Centre for Rural Development and Technology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
| | - Virendra Kumar Vijay
- Centre for Rural Development and Technology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India
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Yan M, Tian H, Song S, Tan HTW, Lee JTE, Zhang J, Sharma P, Tiong YW, Tong YW. Effects of digestate-encapsulated biochar on plant growth, soil microbiome and nitrogen leaching. J Environ Manage 2023; 334:117481. [PMID: 36801683 DOI: 10.1016/j.jenvman.2023.117481] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/22/2023] [Accepted: 02/06/2023] [Indexed: 06/18/2023]
Abstract
The increasing amount of food waste and the excessive use of mineral fertilizers have caused detrimental impacts on soil, water, and air quality. Though digestate derived from food waste has been reported to partially replace fertilizer, its efficiency requires further improvement. In this study, the effects of digestate-encapsulated biochar were comprehensively investigated based on growth of an ornamental plant, soil characteristics, nutrient leaching and soil microbiome. Results showed that except for biochar, the tested fertilizers and soil additives, i.e., digestate, compost, commercial fertilizer, digestate-encapsulated biochar had positive effects on plants. Especially, the digestate-encapsulated biochar had the best effectiveness as evidenced by 9-25% increase in chlorophyll content index, fresh weight, leaf area and blossom frequency. For the effects of fertilizers or soil additives on soil characteristics and nutrient retention, the digestate-encapsulated biochar leached least N-nutrients (<8%), while the compost, digestate and mineral fertilizer leached up to 25% N-nutrients. All the treatments had minimal effects on the soil properties of pH and electrical conductivity. According to the microbial analysis, the digestate-encapsulated biochar has the comparable role with compost in improving the soil immune system against pathogen infection. The metagenomics coupling with qPCR analysis suggested that digestate-encapsulated biochar boosted the nitrification process and inhibited the denitrification process. This study provides an extensive understanding into the impacts of the digestate-encapsulated biochar on an ornamental plant and offers practical implications for the choice of sustainable fertilizers or soil additives and food-waste digestate management.
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Affiliation(s)
- Miao Yan
- Laboratory of Biomass Bio-chemical Conversion, Guang Zhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou, 510640, PR China; Environmental Research Institute, National University of Singapore, Singapore
| | - Hailin Tian
- Environmental Research Institute, National University of Singapore, Singapore; Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, 510006, PR China
| | - Shuang Song
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Hugh T W Tan
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Jonathan T E Lee
- Environmental Research Institute, National University of Singapore, Singapore; Energy and Environmental Sustainability for Megacities (E2S2), Campus for Research Excellence and Technological Enterprise (CREATE), 1 Create Way, Singapore, 138602, Singapore
| | - Jingxin Zhang
- China-UK Low Carbon College, Shanghai Jiao Tong University, Shanghai, 201306, PR China
| | - Pooja Sharma
- Environmental Research Institute, National University of Singapore, Singapore
| | - Yong Wei Tiong
- Environmental Research Institute, National University of Singapore, Singapore
| | - Yen Wah Tong
- Department of Chemical & Biomolecular Engineering, National University of Singapore, Singapore.
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Kintl A, Hammerschmiedt T, Vítěz T, Brtnický M, Vejražka K, Huňady I, Látal O, Elbl J. Possibility of using tannins to control greenhouse gas production during digestate storage. Waste Manag 2023; 156:75-83. [PMID: 36442329 DOI: 10.1016/j.wasman.2022.11.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/19/2022] [Accepted: 11/16/2022] [Indexed: 06/16/2023]
Abstract
The presented paper deals with the testing of a possibility to reduce emissions of undesirable greenhouse gases (CH4, CO2; NOx) and their mixture (biogas) during the storage of digestate using applications of secondary plant metabolites (tannins). The experiment was conducted in laboratory conditions in which the digestate was placed in fermentation chambers. Prior to the fermentation process, preparations were applied to the digestate, which contained tannins: Tanenol Antibotrytis (TA), Tanenol Clar (TC) and Tanenol Rouge (TR) in three concentrations (0.5, 1.0 and 2.0% w/w). The application of these preparations demonstrably affected the production of biogas and the contents of CH4, CO2 and N therein. The application of TR preparation in the concentration of 1.0% and 2.0% significantly reduced the production of biogas as compared with all variants. The preparation further inhibited the process of CH4 development. In contrast, the other preparations with the content of different kinds of TA and TC increased the production of biogas (on average by 15%), CH4 (on average by 7%) and CO2 (on average by 12%) as compared with the control variant and TR variant. These two variants reduced the concentration of N in biogas on average by 38%. Thus, the tested Tanenol tannin preparations can be used in different concentrations either to control emissions of greenhouse gases during the storage of digestate or, in case of increased production of CO2 for its reuse in order to increase methane yields in the process of anaerobic fermentation.
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Affiliation(s)
- Antonín Kintl
- Agricultural Research, Ltd., Zahradní 1, 664 41 Troubsko, Czech Republic.
| | - Tereza Hammerschmiedt
- Department of Agrochemistry, Soil Science, Microbiology and Plant Nutrition, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic.
| | - Tomáš Vítěz
- Department of Agricultural, Food and Environmental Engineering, Faculty of AgriSciences, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic.
| | - Martin Brtnický
- Department of Agrochemistry, Soil Science, Microbiology and Plant Nutrition, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic; Institute of Chemistry and Technology of Environmental Protection, Brno University of Technology, Faculty of Chemistry, Purkynova 118, 621 00 Brno, Czech Republic.
| | - Karel Vejražka
- Agricultural Research, Ltd., Zahradní 1, 664 41 Troubsko, Czech Republic.
| | - Igor Huňady
- Agricultural Research, Ltd., Zahradní 1, 664 41 Troubsko, Czech Republic.
| | - Oldřich Látal
- Department of Agrochemistry, Soil Science, Microbiology and Plant Nutrition, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic.
| | - Jakub Elbl
- Agricultural Research, Ltd., Zahradní 1, 664 41 Troubsko, Czech Republic; Department of Agrosystems and Bioclimatology, Faculty of AgriSciences, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic.
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Ferrillo A, Kobel CM, Vera-Ponce de León A, La Rosa SL, Kunath BJ, Pope PB, Hagen LH. Long-Read Metagenomics and CAZyme Discovery. Methods Mol Biol 2023; 2657:253-284. [PMID: 37149537 DOI: 10.1007/978-1-0716-3151-5_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Microorganisms play a primary role in regulating biogeochemical cycles and are a valuable source of enzymes that have biotechnological applications, such as carbohydrate-active enzymes (CAZymes). However, the inability to culture the majority of microorganisms that exist in natural ecosystems restricts access to potentially novel bacteria and beneficial CAZymes. While commonplace molecular-based culture-independent methods such as metagenomics enable researchers to study microbial communities directly from environmental samples, recent progress in long-read sequencing technologies are advancing the field. We outline key methodological stages that are required as well as describe specific protocols that are currently used for long-read metagenomic projects dedicated to CAZyme discovery.
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Affiliation(s)
- Alessandra Ferrillo
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway
| | - Carl Mathias Kobel
- Faculty of Bioscience, Norwegian University of Life Sciences, Aas, Norway
| | - Arturo Vera-Ponce de León
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway
- Faculty of Bioscience, Norwegian University of Life Sciences, Aas, Norway
| | - Sabina Leanti La Rosa
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway
| | | | - Phillip Byron Pope
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway
- Faculty of Bioscience, Norwegian University of Life Sciences, Aas, Norway
| | - Live Heldal Hagen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway.
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Li C, Wei Z, Yang P, Shan J, Yan X. Conversion from rice fields to vegetable fields alters product stoichiometry of denitrification and increases N 2O emission. Environ Res 2022; 215:114279. [PMID: 36126691 DOI: 10.1016/j.envres.2022.114279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 08/30/2022] [Accepted: 09/02/2022] [Indexed: 06/15/2023]
Abstract
Information about effects of conversion from rice fields to vegetable fields on denitrification process is still limited. In this study, denitrification rate and product ratio (i.e., N2O/(N2O + N2) ratio) were investigated by soil-core incubation based N2/Ar technique in one rice paddy field (RP) and two vegetable fields (VF4 and VF7, 4 and 7 years vegetable cultivating after conversion from rice fields, respectively). Genes related to denitrification and bacterial community composition were quantified to investigate the microbial mechanisms behind the effects of land-use conversion. The results showed that conversion of rice fields to vegetable fields did not significantly change denitrification rate although the abundance of denitrification related genes was significantly reduced by 79.22%-99.84% in the vegetable soils. Whereas, compared with the RP soil, N2O emission rate was significantly (P < 0.05) increased by 53.5 and 1.6 times in the VF4 and VF7 soils, respectively. Correspondingly, the N2O/(N2O + N2) ratio increased from 0.18% (RP soil) to 5.65% and 0.65% in the VF4 and VF7 soils, respectively. These changes were mainly attributed to the lower pH, higher nitrate content, and the altered bacterial community composition in the vegetable soils. Overall, our results showed that conversion of rice fields to vegetable fields increased the N2O emission rate and altered the product ratio of denitrification. This may increase the contribution of land-use conversion to global warming and stratospheric ozone depletion.
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Affiliation(s)
- Chenglin Li
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Changshu National Agro-Ecosystem Observation and Research Station, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Zhijun Wei
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Changshu National Agro-Ecosystem Observation and Research Station, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Pinpin Yang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Jun Shan
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China; Changshu National Agro-Ecosystem Observation and Research Station, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
| | - Xiaoyuan Yan
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China; Changshu National Agro-Ecosystem Observation and Research Station, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
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Oba K, Suenaga T, Kuroiwa M, Riya S, Terada A. Exploring the Functions of Efficient Canonical Denitrifying Bacteria as N 2O Sinks: Implications from 15N Tracer and Transcriptome Analyses. Environ Sci Technol 2022; 56:11694-11706. [PMID: 35917165 DOI: 10.1021/acs.est.2c02119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In denitrifying reactors, canonical complete denitrifying bacteria reduce nitrate (NO3-) to nitrogen via N2O. However, they can also produce N2O under certain conditions. We used a 15N tracer method, in which 15N-labeled NO3-/nitrite (NO2-) and nonlabeled N2O were simultaneously supplied with organic electron donors to five canonical complete denitrifying bacteria affiliated with either Clade I or Clade II nosZ. We calculated their NO3-, NO2-, and N2O consumption rates. The Clade II nosZ bacterium Azospira sp. strain I13 had the highest N2O consumption rate (3.47 ± 0.07 fmol/cell/h) and the second lowest NO3- consumption rate (0.20 ± 0.03 fmol/cell/h); hence, it is a N2O sink. A change from peptone- to acetate/citrate-based organic electron donors increased the NO3- consumption rate by 4.8 fold but barely affected the N2O consumption rate. Electron flow was directed to N2O rather than NO3- in Azospira sp. strain I13 and Az. oryzae strain PS only exerting a N2O sink but to NO3- in the Clade I nosZ N2O-reducing bacteria Pseudomonas stutzeri strain JCM 5965 and Alicycliphilus denitrificans strain I51. Transcriptome analyses revealed that the genotype could not fully describe the phenotype. The results show that N2O production and consumption differ among canonical denitrifying bacteria and will be useful for developing N2O mitigation strategies.
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Affiliation(s)
- Kohei Oba
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-Cho, Koganei, Tokyo 184-8588, Japan
| | - Toshikazu Suenaga
- Global Innovation Research Institute, Tokyo University of Agriculture and Technology, 3-8-1 Harumi-Cho, Fuchu, Tokyo 185-8538, Japan
- Department of Chemical Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-hiroshima, Hiroshima 739-8527, Japan
| | - Megumi Kuroiwa
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-Cho, Koganei, Tokyo 184-8588, Japan
| | - Shohei Riya
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-Cho, Koganei, Tokyo 184-8588, Japan
- Global Innovation Research Institute, Tokyo University of Agriculture and Technology, 3-8-1 Harumi-Cho, Fuchu, Tokyo 185-8538, Japan
| | - Akihiko Terada
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-Cho, Koganei, Tokyo 184-8588, Japan
- Global Innovation Research Institute, Tokyo University of Agriculture and Technology, 3-8-1 Harumi-Cho, Fuchu, Tokyo 185-8538, Japan
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Jonassen KR, Ormåsen I, Duffner C, Hvidsten TR, Bakken LR, Vick SHW. A Dual Enrichment Strategy Provides Soil- and Digestate-Competent Nitrous Oxide-Respiring Bacteria for Mitigating Climate Forcing in Agriculture. mBio 2022; 13:e0078822. [PMID: 35638872 DOI: 10.1128/mbio.00788-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Manipulating soil metabolism through heavy inoculation with microbes is feasible if organic wastes can be utilized as the substrate for growth and vector as a fertilizer. This, however, requires organisms active in both digestate and soil (generalists). Here, we present a dual enrichment strategy to enrich and isolate such generalists among N2O-respiring bacteria (NRB) in soil and digestates, to be used as an inoculum for strengthening the N2O-reduction capacity of soils. The enrichment strategy utilizes sequential batch enrichment cultures alternating between sterilized digestate and soil as substrates, with each batch initiated with limited O2 and unlimited N2O. The cultures were monitored for gas kinetics and community composition. As predicted by a Lotka-Volterra competition model, cluster analysis identified generalist operational taxonomic units (OTUs) which became dominant, digestate/soil-specialists which did not, and a majority that were gradually diluted out. We isolated several NRBs circumscribed by generalist OTUs. Their denitrification genes and phenotypes predicted a variable capacity to act as N2O-sinks, while all genomes predicted broad catabolic capacity. The latter contrasts with previous attempts to enrich NRB by anaerobic incubation of unsterilized digestate only, which selected for organisms with a catabolic capacity limited to fermentation products. The two isolates with the most promising characteristics as N2O sinks were aPseudomonas sp. with a full-fledged denitrification-pathway and a Cloacibacterium sp. carrying only N2O reductase (clade II), and soil experiments confirmed their capacity to reduce N2O-emissions from soil. The successful enrichment of NRB with broad catabolic spectra suggests that the concept of dual enrichment should also be applicable for enrichment of generalists with traits other than N2O reduction.
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Ying X, Fu J, Zeng M, Liu W, Zhang T, Shen P, Zhang X. BiOCl-Fe 2O 3@TiO 2 Mesoporous Composite for Photoelectrochemical Synthesis of Ammonia. Acta Chimica Sinica 2022. [DOI: 10.6023/a21120562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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