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Fu K, Zhang X, Fan Y, Bian Y, Qiu F, Cao X. The enrichment characterisation of Nitrospira under high DO conditions. ENVIRONMENTAL TECHNOLOGY 2024; 45:2156-2170. [PMID: 36601901 DOI: 10.1080/09593330.2023.2165457] [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: 09/18/2022] [Accepted: 12/31/2022] [Indexed: 06/17/2023]
Abstract
Nitrite-oxidizing bacteria (NOB) are crucial to nitrification and nitrogen elimination in wastewater treatment. Mass reports exist on the links between NOB and other microorganisms, for instance, ammonia-oxidizing bacteria (AOB). However, a few studies exist on the enrichment characterisation of NOB under high dissolved oxygen (DO) conditions. In this study, NOB was designed to be enriched individually under high DO conditions in a continuous aeration sequencing batch reactor (SBR), and the kinetic characterisation of NOB was evaluated. The analysis revealed that the average NO2--N removal rate was steady above 98%, with DO and NO2--N being 3-5 mg L-1 and 50-450 mg L-1, respectively. The NO2--N removal efficiency of the system was significantly enhanced and better than in other studies. The high-throughput sequencing suggested that Parcubacteria_ genera_incertae_sedis was the first dominant genus (21.99%), which often appeared in the NOB biological community with Nitrospira. However, the dominant genus NOB was Nitrospira rather than Nitrobacter (8.49%). This result suggested that Nitrospira was capable of higher NO2--N removal. But lower relative abundance indicated that excessive NO2--N had an adverse effect on the enrichment and activity of Nitrospira. In addition, the nitrite half-saturation constant (KNO2) and the oxygen half-saturation constant (KO) were 1.71 ± 0.19 mg L-1 and 0.95 ± 0.10 mg L-1, respectively. These results showed that the enriched Nitrospira bacteria had different characteristics at the strain level, which can be used as a theoretical basis for wastewater treatment plant design and optimisation.
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Affiliation(s)
- Kunming Fu
- Key Laboratory of Urban Storm Water System and Water Environment Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing, People's Republic of China
- School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing, People's Republic of China
| | - Xuemeng Zhang
- School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing, People's Republic of China
| | - Yang Fan
- School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing, People's Republic of China
| | - Yihao Bian
- School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing, People's Republic of China
| | - Fuguo Qiu
- School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing, People's Republic of China
| | - Xiuqin Cao
- School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing, People's Republic of China
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Murakami C, Tanaka AR, Sato Y, Morimoto K. Buffer-free CAS assay using a diluted growth medium efficiently detects siderophore production and microbial growth. Biometals 2024; 37:223-232. [PMID: 37848652 DOI: 10.1007/s10534-023-00544-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 09/20/2023] [Indexed: 10/19/2023]
Abstract
Siderophores are iron chelators and low-molecular-weight compounds secreted by various microorganisms under low-iron conditions. Many microorganisms produce siderophores in the natural environment as iron is an essential element for many of them. CAS assays are widely used to detect siderophores in cultures of various microorganisms; however, it is necessary to improve their sensitivity for the efficient application to fastidious microorganisms. We developed a simple, high-throughput CAS assay employing a buffer-free CAS reagent and diluted growth medium (10% dR2A) in a 96-well microplate. Using a diluted growth medium in agar plates suitable for iron-restricted conditions supported siderophore production by microorganisms from activated sludge. A buffer-free CAS reagent combined with a diluted growth medium revealed that these microorganisms tended to produce more siderophores or iron chelators than microorganisms under iron-rich conditions. Moreover, this buffer-free CAS assay easily and efficiently detected not only siderophore production but also the growth of fastidious microorganisms.
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Affiliation(s)
- Chiho Murakami
- Faculty of Pharmacy, Yasuda Women's University, 6-13-1 Yasuhigashi, Hiroshima City, Hiroshima Prefecture, 731-0153, Japan.
| | - Arowu R Tanaka
- Faculty of Pharmacy, Yasuda Women's University, 6-13-1 Yasuhigashi, Hiroshima City, Hiroshima Prefecture, 731-0153, Japan
| | - Yuichiro Sato
- Faculty of Pharmacy, Yasuda Women's University, 6-13-1 Yasuhigashi, Hiroshima City, Hiroshima Prefecture, 731-0153, Japan
| | - Kinjiro Morimoto
- Faculty of Pharmacy, Yasuda Women's University, 6-13-1 Yasuhigashi, Hiroshima City, Hiroshima Prefecture, 731-0153, Japan
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Ide H, Ishii K, Takahashi Y, Fujitani H, Tsuneda S. Effects of Co-existing Heterotrophs on Physiology of and Nitrogen Metabolism in Autotrophic Nitrite-oxidizing Candidatus Nitrotoga. Microbes Environ 2023; 38:ME23076. [PMID: 38072409 PMCID: PMC10728634 DOI: 10.1264/jsme2.me23076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 10/18/2023] [Indexed: 12/18/2023] Open
Abstract
Interactions between autotrophic nitrifiers and heterotrophs have attracted considerable attention in microbial ecology. However, the mechanisms by which heterotrophs affect the physiological activity of and nitrogen metabolism in autotrophic nitrite oxidizers remain unclear. We herein focused on nitrite-oxidizing Candidatus Nitrotoga and compared an axenic culture including only Ca. Nitrotoga with a co-culture of both Ca. Nitrotoga and Acidovorax in physiological experiments and transcriptomics. In the co-culture with Acidovorax, nitrite consumption by Ca. Nitrotoga was promoted, and some genes relevant to nitrogen metabolism in Ca. Nitrotoga were highly expressed. These results provide insights into the mechanisms by which co-existing heterotrophs affect autotrophic nitrifiers.
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Affiliation(s)
- Hiroto Ide
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan
| | - Kento Ishii
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan
- Research Organization for Nano & Life Innovation, Waseda University, Tokyo, Japan
| | - Yu Takahashi
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan
| | - Hirotsugu Fujitani
- Research Organization for Nano & Life Innovation, Waseda University, Tokyo, Japan
- Department of Biological Sciences, Chuo University, Tokyo, Japan
| | - Satoshi Tsuneda
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan
- Research Organization for Nano & Life Innovation, Waseda University, Tokyo, Japan
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Liu B, Lin W, Huang S, Sun Q, Yin H, Luo J. Removal of Mg 2+ inhibition benefited the growth and isolation of ammonia-oxidizing bacteria: An inspiration from bacterial interaction. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:155923. [PMID: 35577082 DOI: 10.1016/j.scitotenv.2022.155923] [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: 04/19/2022] [Revised: 05/09/2022] [Accepted: 05/10/2022] [Indexed: 06/15/2023]
Abstract
Ammonia-oxidizing bacteria (AOB) play an important role in the global nitrogen cycle and have broad applications in the nitrogen removal from wastewater. However, the AOB species are sensitive to environmental factors and usually form tight relationships with other microbes, making the AOB isolation and maintenance are difficult and time-consuming. In this study, the relationship that occurred between AOB and their bacterial partners was found to be able to improve the ammonia oxidation; during the co-cultivation, the magnesium ions (Mg2+) with removal rate as high as 36.7% was removed from culture medium by the concomitant bacterial species, which was regarded as the main reason for improving ammonia oxidation. During the pure cultivation of AOB isolate, when the concentration of Mg2+ reduced to low levels, the ammonia-oxidizing activity was more than 5 times and the amoA gene expression was more than 12 times higher than that grown in the initial culture medium. Based on a newly designed culture medium, the ammonia oxidation of AOB isolate grown in liquid culture was significantly promoted and the visible AOB colonies with much more number and larger diameter were observed to form on agar plates. With the addition of high concentration of calcium carbonate (CaCO3), AOB colonies could be easily and specifically identified by following the hydrolytic zones that formed around AOB colonies. Another AOB isolates were successively obtained from different samples and within a short time, suggesting the feasibility and effectivity of this culture medium and strategy on the AOB isolation from environments.
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Affiliation(s)
- Buchan Liu
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, PR China
| | - Weitie Lin
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, PR China; MOE Joint International Research Laboratory of Synthetic Biology and Medicine, South China University of Technology, Guangzhou 510006, PR China
| | - Shenxi Huang
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, PR China
| | - Qiuyun Sun
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, PR China
| | - Hao Yin
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, PR China
| | - Jianfei Luo
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, PR China; MOE Joint International Research Laboratory of Synthetic Biology and Medicine, South China University of Technology, Guangzhou 510006, PR China.
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Oshiki M, Takaki Y, Hirai M, Nunoura T, Kamigaito A, Okabe S. Metagenomic Analysis of Five Phylogenetically Distant Anammox Bacterial Enrichment Cultures. Microbes Environ 2022; 37. [PMID: 35811137 PMCID: PMC9530715 DOI: 10.1264/jsme2.me22017] [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] [Indexed: 11/22/2022] Open
Abstract
Anaerobic ammonium-oxidizing (anammox) bacteria are slow-growing and fastidious bacteria, and limited numbers of enrichment cultures have been established. A metagenomic analysis of our 5 established anammox bacterial enrichment cultures was performed in the present study. Fourteen high-quality metagenome-assembled genomes (MAGs) were obtained, including those of 5 anammox Planctomycetota (Candidatus Brocadia, Ca. Kuenenia, Ca. Jettenia, and Ca. Scalindua), 4 Bacteroidota, and 3 Chloroflexota. Based on the gene sets of metabolic pathways involved in the degradation of polymeric substances found in Chloroflexota and Bacteroidota MAGs, they are expected to be scavengers of extracellular polymeric substances and cell debris.
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Affiliation(s)
- Mamoru Oshiki
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University
| | - Yoshihiro Takaki
- Super-cutting-edge Grand and Advanced Research (SUGAR) Program, Institute for Extra-cutting-edge Science and Technology Avant-garde Research (X-STAR), Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
| | - Miho Hirai
- Super-cutting-edge Grand and Advanced Research (SUGAR) Program, Institute for Extra-cutting-edge Science and Technology Avant-garde Research (X-STAR), Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
| | - Takuro Nunoura
- Research Center for Bioscience and Nanoscience (CeBN), JAMSTEC
| | - Atsushi Kamigaito
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University
| | - Satoshi Okabe
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University
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