Kinetics and New Mechanism of Azoxystrobin Biodegradation by an <em>Ochrobactrum anthropi</em> Strain SH14
Azoxystrobin is one of the most popular strobilurin fungicides, widely used in agricultural fields for decades.Extensive use of azoxystrobin poses a major threat to ecosystems. However, little is known about the kinetics and mechanism of azoxystrobin biodegradation. The present study reports a newly...
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MDPI AG
2020-04-01
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| Series: | Microorganisms |
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| Online Access: | https://www.mdpi.com/2076-2607/8/5/625 |
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| author | Yanmei Feng Wenping Zhang Shimei Pang Ziqiu Lin Yuming Zhang Yaohua Huang Pankaj Bhatt Shaohua Chen |
| author_facet | Yanmei Feng Wenping Zhang Shimei Pang Ziqiu Lin Yuming Zhang Yaohua Huang Pankaj Bhatt Shaohua Chen |
| author_sort | Yanmei Feng |
| collection | DOAJ |
| description | Azoxystrobin is one of the most popular strobilurin fungicides, widely used in agricultural fields for decades.Extensive use of azoxystrobin poses a major threat to ecosystems. However, little is known about the kinetics and mechanism of azoxystrobin biodegradation. The present study reports a newly isolated bacterial strain, <i>Ochrobactrum anthropi</i> SH14, utilizing azoxystrobin as a sole carbon source, was isolated from contaminated soils. Strain SH14 degraded 86.3% of azoxystrobin (50 μg·mL<sup>−1</sup>) in a mineral salt medium within five days. Maximum specific degradation rate (<i>q</i><sub>max</sub>), half-saturation constant (<i>K<sub>s</sub></i>), and inhibition constant (<i>K<sub>i</sub></i>) were noted as 0.6122 d<sup>−1</sup>, 6.8291 μg·mL<sup>−1</sup>, and 188.4680 μg·mL<sup>−1</sup>, respectively.Conditions for strain SH14 based azoxystrobin degradation were optimized by response surface methodology. Optimum degradation was determined to be 30.2 °C, pH 7.9, and 1.1 × 10<sup>7</sup> CFU·mL<sup>−1</sup> of inoculum. Strain SH14 degraded azoxystrobin via a novel metabolic pathway with the formation of <i>N</i>-(4,6-dimethoxypyrimidin-2-yl)-acetamide,2-amino-4-(4-chlorophenyl)-3-cyano-5,6-dimethyl-pyridine, and 3-quinolinecarboxylic acid,6,8-difluoro-4-hydroxy-ethyl ester as the main intermediate products, which were further transformed without any persistent accumulative product. This is the first report of azoxystrobin degradation pathway in a microorganism. Strain SH14 also degraded other strobilurin fungicides, including kresoxim-methyl (89.4%), pyraclostrobin (88.5%), trifloxystrobin (78.7%), picoxystrobin (76.6%), and fluoxastrobin (57.2%) by following first-order kinetic model. Bioaugmentation of azoxystrobin-contaminated soils with strain SH14 remarkably enhanced the degradation of azoxystrobin, and its half-life was substantially reduced by 95.7 and 65.6 days in sterile and non-sterile soils, respectively, in comparison with the controls without strain SH14. The study presents <i>O. anthropi</i> SH14 for enhanced biodegradation of azoxystrobin and elaborates on the metabolic pathways to eliminate its residual toxicity from the environment. |
| first_indexed | 2024-03-10T20:12:44Z |
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| spelling | doaj.art-b1130819dcab4230b42ae22b4ce0a9f42023-11-19T22:48:07ZengMDPI AGMicroorganisms2076-26072020-04-018562510.3390/microorganisms8050625Kinetics and New Mechanism of Azoxystrobin Biodegradation by an <em>Ochrobactrum anthropi</em> Strain SH14Yanmei Feng0Wenping Zhang1Shimei Pang2Ziqiu Lin3Yuming Zhang4Yaohua Huang5Pankaj Bhatt6Shaohua Chen7State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, ChinaState Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, ChinaState Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, ChinaState Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, ChinaState Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, ChinaState Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, ChinaState Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, ChinaState Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, ChinaAzoxystrobin is one of the most popular strobilurin fungicides, widely used in agricultural fields for decades.Extensive use of azoxystrobin poses a major threat to ecosystems. However, little is known about the kinetics and mechanism of azoxystrobin biodegradation. The present study reports a newly isolated bacterial strain, <i>Ochrobactrum anthropi</i> SH14, utilizing azoxystrobin as a sole carbon source, was isolated from contaminated soils. Strain SH14 degraded 86.3% of azoxystrobin (50 μg·mL<sup>−1</sup>) in a mineral salt medium within five days. Maximum specific degradation rate (<i>q</i><sub>max</sub>), half-saturation constant (<i>K<sub>s</sub></i>), and inhibition constant (<i>K<sub>i</sub></i>) were noted as 0.6122 d<sup>−1</sup>, 6.8291 μg·mL<sup>−1</sup>, and 188.4680 μg·mL<sup>−1</sup>, respectively.Conditions for strain SH14 based azoxystrobin degradation were optimized by response surface methodology. Optimum degradation was determined to be 30.2 °C, pH 7.9, and 1.1 × 10<sup>7</sup> CFU·mL<sup>−1</sup> of inoculum. Strain SH14 degraded azoxystrobin via a novel metabolic pathway with the formation of <i>N</i>-(4,6-dimethoxypyrimidin-2-yl)-acetamide,2-amino-4-(4-chlorophenyl)-3-cyano-5,6-dimethyl-pyridine, and 3-quinolinecarboxylic acid,6,8-difluoro-4-hydroxy-ethyl ester as the main intermediate products, which were further transformed without any persistent accumulative product. This is the first report of azoxystrobin degradation pathway in a microorganism. Strain SH14 also degraded other strobilurin fungicides, including kresoxim-methyl (89.4%), pyraclostrobin (88.5%), trifloxystrobin (78.7%), picoxystrobin (76.6%), and fluoxastrobin (57.2%) by following first-order kinetic model. Bioaugmentation of azoxystrobin-contaminated soils with strain SH14 remarkably enhanced the degradation of azoxystrobin, and its half-life was substantially reduced by 95.7 and 65.6 days in sterile and non-sterile soils, respectively, in comparison with the controls without strain SH14. The study presents <i>O. anthropi</i> SH14 for enhanced biodegradation of azoxystrobin and elaborates on the metabolic pathways to eliminate its residual toxicity from the environment.https://www.mdpi.com/2076-2607/8/5/625azoxystrobin<i>Ochrobactrum anthropi</i> SH14biodegradationkineticsmetabolic pathway |
| spellingShingle | Yanmei Feng Wenping Zhang Shimei Pang Ziqiu Lin Yuming Zhang Yaohua Huang Pankaj Bhatt Shaohua Chen Kinetics and New Mechanism of Azoxystrobin Biodegradation by an <em>Ochrobactrum anthropi</em> Strain SH14 Microorganisms azoxystrobin <i>Ochrobactrum anthropi</i> SH14 biodegradation kinetics metabolic pathway |
| title | Kinetics and New Mechanism of Azoxystrobin Biodegradation by an <em>Ochrobactrum anthropi</em> Strain SH14 |
| title_full | Kinetics and New Mechanism of Azoxystrobin Biodegradation by an <em>Ochrobactrum anthropi</em> Strain SH14 |
| title_fullStr | Kinetics and New Mechanism of Azoxystrobin Biodegradation by an <em>Ochrobactrum anthropi</em> Strain SH14 |
| title_full_unstemmed | Kinetics and New Mechanism of Azoxystrobin Biodegradation by an <em>Ochrobactrum anthropi</em> Strain SH14 |
| title_short | Kinetics and New Mechanism of Azoxystrobin Biodegradation by an <em>Ochrobactrum anthropi</em> Strain SH14 |
| title_sort | kinetics and new mechanism of azoxystrobin biodegradation by an em ochrobactrum anthropi em strain sh14 |
| topic | azoxystrobin <i>Ochrobactrum anthropi</i> SH14 biodegradation kinetics metabolic pathway |
| url | https://www.mdpi.com/2076-2607/8/5/625 |
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