Nitrite Degradation by a Novel Marine Bacterial Strain <i>Pseudomonas aeruginosa</i> DM6: Characterization and Metabolic Pathway Analysis
High concentrations of nitrite in marine aquaculture wastewater not only pose a threat to the survival and immune systems of aquatic organisms but also contribute to eutrophication, thereby impacting the balance of coastal ecosystems. Compared to traditional physical and chemical methods, utilizing...
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MDPI AG
2024-03-01
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| Online Access: | https://www.mdpi.com/2073-4441/16/5/784 |
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| author | Zhe Chen Wenying Yu Yingjian Zhan Zheng Chen Tengda Han Weiwei Song Yueyue Zhou |
| author_facet | Zhe Chen Wenying Yu Yingjian Zhan Zheng Chen Tengda Han Weiwei Song Yueyue Zhou |
| author_sort | Zhe Chen |
| collection | DOAJ |
| description | High concentrations of nitrite in marine aquaculture wastewater not only pose a threat to the survival and immune systems of aquatic organisms but also contribute to eutrophication, thereby impacting the balance of coastal ecosystems. Compared to traditional physical and chemical methods, utilizing microorganism-mediated biological denitrification is a cost-effective and efficient solution. However, the osmotic pressure changes and salt-induced enzyme precipitation in high-salinity seawater aquaculture environments may inhibit the growth and metabolism of freshwater bacterial strains, making it more suitable to select salt-tolerant marine microorganisms for treating nitrite in marine aquaculture wastewater. In this study, a salt-tolerant nitrite-degrading bacterium, designated as DM6, was isolated from the seawater (salinity of 25–30‰) of <i>Portunus trituberculatus</i> cultivation. The molecular identification of strain DM6 was conducted using 16S rRNA gene sequencing technology. The impacts of various environmental factors on the nitrite degradation performance of strain DM6 were investigated through single-factor and orthogonal experiments, with the selected conditions considered to be the key factors affecting the denitrification efficiency of microorganisms in actual wastewater treatment. PCR amplification of key genes involved in the nitrite metabolism pathway of strain DM6 was conducted, including denitrification pathway-related genes narG, narH, narI, nirS, and norB, as well as assimilation pathway-related genes nasC, nasD, nasE, glnA, gltB, gltD, gdhB, and gdhA. The findings indicated that strain DM6 is classified as <i>Pseudomonas aeruginosa</i> and exhibits efficient nitrite degradation even under a salinity of 35‰. The optimal nitrite degradation efficiency of DM6 was observed when using sodium citrate as the carbon source, a C/N ratio of 20, a salinity of 13‰, pH 8.0, and a temperature of 35 °C. Under these conditions, DM6 could completely degrade an initial nitrite concentration of 156.33 ± 1.17 mg/L within 36 h. Additionally, the successful amplification of key genes involved in the nitrite denitrification and assimilation pathways suggests that strain DM6 may possess both denitrification and assimilation pathways for nitrite degradation simultaneously. Compared to freshwater strains, strain DM6 demonstrates higher salt tolerance and exhibits strong nitrite degradation capability even at high concentrations. However, it may be more suitable for application in the treatment of wastewater from marine aquaculture systems during summer, high-temperature, or moderately alkaline conditions. |
| first_indexed | 2024-04-25T00:18:54Z |
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| language | English |
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| spelling | doaj.art-6fdfa7ec57af4f40bac5e9976db6fe1a2024-03-12T16:58:04ZengMDPI AGWater2073-44412024-03-0116578410.3390/w16050784Nitrite Degradation by a Novel Marine Bacterial Strain <i>Pseudomonas aeruginosa</i> DM6: Characterization and Metabolic Pathway AnalysisZhe Chen0Wenying Yu1Yingjian Zhan2Zheng Chen3Tengda Han4Weiwei Song5Yueyue Zhou6Marine Economic Research Center, Donghai Academy, Ningbo University, Ningbo 315000, ChinaMarine Economic Research Center, Donghai Academy, Ningbo University, Ningbo 315000, ChinaMarine Economic Research Center, Donghai Academy, Ningbo University, Ningbo 315000, ChinaMarine Economic Research Center, Donghai Academy, Ningbo University, Ningbo 315000, ChinaMarine Economic Research Center, Donghai Academy, Ningbo University, Ningbo 315000, ChinaMarine Economic Research Center, Donghai Academy, Ningbo University, Ningbo 315000, ChinaMarine Economic Research Center, Donghai Academy, Ningbo University, Ningbo 315000, ChinaHigh concentrations of nitrite in marine aquaculture wastewater not only pose a threat to the survival and immune systems of aquatic organisms but also contribute to eutrophication, thereby impacting the balance of coastal ecosystems. Compared to traditional physical and chemical methods, utilizing microorganism-mediated biological denitrification is a cost-effective and efficient solution. However, the osmotic pressure changes and salt-induced enzyme precipitation in high-salinity seawater aquaculture environments may inhibit the growth and metabolism of freshwater bacterial strains, making it more suitable to select salt-tolerant marine microorganisms for treating nitrite in marine aquaculture wastewater. In this study, a salt-tolerant nitrite-degrading bacterium, designated as DM6, was isolated from the seawater (salinity of 25–30‰) of <i>Portunus trituberculatus</i> cultivation. The molecular identification of strain DM6 was conducted using 16S rRNA gene sequencing technology. The impacts of various environmental factors on the nitrite degradation performance of strain DM6 were investigated through single-factor and orthogonal experiments, with the selected conditions considered to be the key factors affecting the denitrification efficiency of microorganisms in actual wastewater treatment. PCR amplification of key genes involved in the nitrite metabolism pathway of strain DM6 was conducted, including denitrification pathway-related genes narG, narH, narI, nirS, and norB, as well as assimilation pathway-related genes nasC, nasD, nasE, glnA, gltB, gltD, gdhB, and gdhA. The findings indicated that strain DM6 is classified as <i>Pseudomonas aeruginosa</i> and exhibits efficient nitrite degradation even under a salinity of 35‰. The optimal nitrite degradation efficiency of DM6 was observed when using sodium citrate as the carbon source, a C/N ratio of 20, a salinity of 13‰, pH 8.0, and a temperature of 35 °C. Under these conditions, DM6 could completely degrade an initial nitrite concentration of 156.33 ± 1.17 mg/L within 36 h. Additionally, the successful amplification of key genes involved in the nitrite denitrification and assimilation pathways suggests that strain DM6 may possess both denitrification and assimilation pathways for nitrite degradation simultaneously. Compared to freshwater strains, strain DM6 demonstrates higher salt tolerance and exhibits strong nitrite degradation capability even at high concentrations. However, it may be more suitable for application in the treatment of wastewater from marine aquaculture systems during summer, high-temperature, or moderately alkaline conditions.https://www.mdpi.com/2073-4441/16/5/784marine bacterial<i>Pseudomonas aeruginosa</i>nitrite degradation characteristicsnitrite transformation pathways |
| spellingShingle | Zhe Chen Wenying Yu Yingjian Zhan Zheng Chen Tengda Han Weiwei Song Yueyue Zhou Nitrite Degradation by a Novel Marine Bacterial Strain <i>Pseudomonas aeruginosa</i> DM6: Characterization and Metabolic Pathway Analysis Water marine bacterial <i>Pseudomonas aeruginosa</i> nitrite degradation characteristics nitrite transformation pathways |
| title | Nitrite Degradation by a Novel Marine Bacterial Strain <i>Pseudomonas aeruginosa</i> DM6: Characterization and Metabolic Pathway Analysis |
| title_full | Nitrite Degradation by a Novel Marine Bacterial Strain <i>Pseudomonas aeruginosa</i> DM6: Characterization and Metabolic Pathway Analysis |
| title_fullStr | Nitrite Degradation by a Novel Marine Bacterial Strain <i>Pseudomonas aeruginosa</i> DM6: Characterization and Metabolic Pathway Analysis |
| title_full_unstemmed | Nitrite Degradation by a Novel Marine Bacterial Strain <i>Pseudomonas aeruginosa</i> DM6: Characterization and Metabolic Pathway Analysis |
| title_short | Nitrite Degradation by a Novel Marine Bacterial Strain <i>Pseudomonas aeruginosa</i> DM6: Characterization and Metabolic Pathway Analysis |
| title_sort | nitrite degradation by a novel marine bacterial strain i pseudomonas aeruginosa i dm6 characterization and metabolic pathway analysis |
| topic | marine bacterial <i>Pseudomonas aeruginosa</i> nitrite degradation characteristics nitrite transformation pathways |
| url | https://www.mdpi.com/2073-4441/16/5/784 |
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