Effects of Pressurized Aeration on the Biodegradation of Short-Chain Chlorinated Paraffins by <i>Escherichia coli</i> Strain 2
Short-chain chlorinated paraffins (SCCPs) were defined as persistent organic pollutants in 2017, and they can migrate and transform in the environment, accumulate in organisms, and amplify through the food chain. Although they pose a serious threat to environmental safety and human health, there are...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-06-01
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| Series: | Membranes |
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| Online Access: | https://www.mdpi.com/2077-0375/12/6/634 |
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| author | Yongxing Qian Wanling Han Fuhai Zhou Bixiao Ji Huining Zhang Kefeng Zhang |
| author_facet | Yongxing Qian Wanling Han Fuhai Zhou Bixiao Ji Huining Zhang Kefeng Zhang |
| author_sort | Yongxing Qian |
| collection | DOAJ |
| description | Short-chain chlorinated paraffins (SCCPs) were defined as persistent organic pollutants in 2017, and they can migrate and transform in the environment, accumulate in organisms, and amplify through the food chain. Although they pose a serious threat to environmental safety and human health, there are few papers on their removal. The current SCCP removal methods are expensive, require severe operating conditions, involve time-consuming biological treatment, and have poor removal specificities. Therefore, it is important to seek efficient methods to remove SCCPs. In this paper, a pressurized reactor was introduced, and the removal performance of SCCPs by <i>Escherichia coli</i> strain 2 was investigated. The results indicated that moderate pure oxygen pressurization promoted bacterial growth, but when it exceeded 0.15 MPa, the bacterial growth was severely inhibited. When the concentration of SCCPs was 20 mg/L, the removal rate of SCCPs was 85.61% under 0.15 MPa pure oxygen pressurization for 7 days, which was 25% higher than at atmospheric pressure (68.83%). In contrast, the removal rate was only 69.28% under 0.15 MPa air pressure. As the pressure continued to increase, the removal rate of SCCPs decreased significantly. The total amount of extracellular polymeric substances (EPS) increased significantly upon increasing the pressure, and the amount of tightly bound EPS (TB-EPS) was higher than that of loosely bound EPS (LB-EPS). The pressure mainly promoted the secretion of proteins in LB-EPS. Furthermore, an appropriate pure oxygen pressure of 0.15 MPa improved the dehydrogenase activity. The gas chromatography–mass spectrometry (GC–MS) results indicated that the degradation pathway possibly involved the cleavage of the C–Cl bond in SCCPs, which produced Cl<sup>−</sup>, followed by C–C bond breaking. This process degraded long-chain alkanes into short-chain alkanes. Moreover, the main degradation products detected were 2,4-dimethylheptane (C<sub>9</sub>H<sub>20</sub>), 2,5-dimethylheptane (C<sub>9</sub>H<sub>20</sub>), and 3,3-dimethylhexane (C<sub>8</sub>H<sub>18</sub>). |
| first_indexed | 2024-03-09T23:04:37Z |
| format | Article |
| id | doaj.art-186244a7fb534d6db45cfcdddc2be628 |
| institution | Directory Open Access Journal |
| issn | 2077-0375 |
| language | English |
| last_indexed | 2024-03-09T23:04:37Z |
| publishDate | 2022-06-01 |
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| series | Membranes |
| spelling | doaj.art-186244a7fb534d6db45cfcdddc2be6282023-11-23T17:55:11ZengMDPI AGMembranes2077-03752022-06-0112663410.3390/membranes12060634Effects of Pressurized Aeration on the Biodegradation of Short-Chain Chlorinated Paraffins by <i>Escherichia coli</i> Strain 2Yongxing Qian0Wanling Han1Fuhai Zhou2Bixiao Ji3Huining Zhang4Kefeng Zhang5School of Civil Engineering and Architecture, NingboTech University, Ningbo 315000, ChinaSchool of Civil Engineering and Architecture, NingboTech University, Ningbo 315000, ChinaZhejiang Haiyi Environmental Protection Equipment Engineering Co., Ltd., Quzhou 324000, ChinaSchool of Civil Engineering and Architecture, NingboTech University, Ningbo 315000, ChinaSchool of Civil Engineering and Architecture, NingboTech University, Ningbo 315000, ChinaSchool of Civil Engineering and Architecture, NingboTech University, Ningbo 315000, ChinaShort-chain chlorinated paraffins (SCCPs) were defined as persistent organic pollutants in 2017, and they can migrate and transform in the environment, accumulate in organisms, and amplify through the food chain. Although they pose a serious threat to environmental safety and human health, there are few papers on their removal. The current SCCP removal methods are expensive, require severe operating conditions, involve time-consuming biological treatment, and have poor removal specificities. Therefore, it is important to seek efficient methods to remove SCCPs. In this paper, a pressurized reactor was introduced, and the removal performance of SCCPs by <i>Escherichia coli</i> strain 2 was investigated. The results indicated that moderate pure oxygen pressurization promoted bacterial growth, but when it exceeded 0.15 MPa, the bacterial growth was severely inhibited. When the concentration of SCCPs was 20 mg/L, the removal rate of SCCPs was 85.61% under 0.15 MPa pure oxygen pressurization for 7 days, which was 25% higher than at atmospheric pressure (68.83%). In contrast, the removal rate was only 69.28% under 0.15 MPa air pressure. As the pressure continued to increase, the removal rate of SCCPs decreased significantly. The total amount of extracellular polymeric substances (EPS) increased significantly upon increasing the pressure, and the amount of tightly bound EPS (TB-EPS) was higher than that of loosely bound EPS (LB-EPS). The pressure mainly promoted the secretion of proteins in LB-EPS. Furthermore, an appropriate pure oxygen pressure of 0.15 MPa improved the dehydrogenase activity. The gas chromatography–mass spectrometry (GC–MS) results indicated that the degradation pathway possibly involved the cleavage of the C–Cl bond in SCCPs, which produced Cl<sup>−</sup>, followed by C–C bond breaking. This process degraded long-chain alkanes into short-chain alkanes. Moreover, the main degradation products detected were 2,4-dimethylheptane (C<sub>9</sub>H<sub>20</sub>), 2,5-dimethylheptane (C<sub>9</sub>H<sub>20</sub>), and 3,3-dimethylhexane (C<sub>8</sub>H<sub>18</sub>).https://www.mdpi.com/2077-0375/12/6/634short-chain chlorinated paraffins<i>Escherichia coli</i> strain 2pressurized aerationremoval mechanism |
| spellingShingle | Yongxing Qian Wanling Han Fuhai Zhou Bixiao Ji Huining Zhang Kefeng Zhang Effects of Pressurized Aeration on the Biodegradation of Short-Chain Chlorinated Paraffins by <i>Escherichia coli</i> Strain 2 Membranes short-chain chlorinated paraffins <i>Escherichia coli</i> strain 2 pressurized aeration removal mechanism |
| title | Effects of Pressurized Aeration on the Biodegradation of Short-Chain Chlorinated Paraffins by <i>Escherichia coli</i> Strain 2 |
| title_full | Effects of Pressurized Aeration on the Biodegradation of Short-Chain Chlorinated Paraffins by <i>Escherichia coli</i> Strain 2 |
| title_fullStr | Effects of Pressurized Aeration on the Biodegradation of Short-Chain Chlorinated Paraffins by <i>Escherichia coli</i> Strain 2 |
| title_full_unstemmed | Effects of Pressurized Aeration on the Biodegradation of Short-Chain Chlorinated Paraffins by <i>Escherichia coli</i> Strain 2 |
| title_short | Effects of Pressurized Aeration on the Biodegradation of Short-Chain Chlorinated Paraffins by <i>Escherichia coli</i> Strain 2 |
| title_sort | effects of pressurized aeration on the biodegradation of short chain chlorinated paraffins by i escherichia coli i strain 2 |
| topic | short-chain chlorinated paraffins <i>Escherichia coli</i> strain 2 pressurized aeration removal mechanism |
| url | https://www.mdpi.com/2077-0375/12/6/634 |
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