JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2020
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IF 4.192
Long Zhang,Ping Hang,Xi-Yi Zhou,Wen-Jing Qiao,Jian-Dong Jiang
Dichlorprop [(RS)-2-(2,4-dichlorophenoxy)propanoic acid; DCPP], an important phenoxyalkanoic acid herbicide (PAAH), is extensively used in the form of racemic mixtures (Rac-DCPP), and the environmental fates of both DCPP enantiomers [(R)-DCPP and (S)-DCPP] mediated by microorganisms are of great concern. In this study, a bacterial strain Sphingopyxis sp. DBS4 was isolated from contaminated soil and was capable of utilizing both (R)-DCPP and (S)-DCPP as the sole carbon source for growth. Strain DBS4 preferentially catabolized (S)-DCPP as compared to (R)-DCPP. The optimal conditions for Rac-DCPP degradation by strain DBS4 were 30 °C and pH 7.0. In addition to Rac-DCPP, other PAAHs such as (RS)-2-(4-chloro-2-methylphenoxy)propanoic acid, 2,4-dichlorophenoxyacetic acid, 4-chloro-2-methylphenoxyacetic acid, and 2,4-dichlorophenoxyacetic acid butyl ester could also be catabolized by strain DBS4. Bioremediation of Rac-DCPP-contaminated soil by inoculation of strain DBS4 exhibited an effective removal of both (R)-DCPP and (S)-DCPP from the soil. Due to its broad substrate spectrum, strain DBS4 showed great potential in the bioremediation of PAAH-contaminated sites.
研究领域:
环境微生物学
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生物修复
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化学生态学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL BIODETERIORATION & BIODEGRADATION
·
2022
·
IF 4.907
Shunli Hu,Long Zhang,Guiping Liu,Yufeng Gan,Baozhan Wang,Fang Wang,Jiandong Jiang
Rac-dichlorprop [( R , S )-2-(2,4-dichlorophenoxy)propanoic acid], a commonly used chiral phenoxyalkanoic acid herbicide, is frequently detected in various environments, posing threats to human health and environmental safety. The ( S )-enantiomer of dichlorprop shows a lower herbicidal activity but a higher toxicity as compared to the ( R )-enantiomer of dichlorprop. It is of great importance to enantioselectively remove the non-herbicidal ( S )-dichlorprop from the rac -dichlorprop in the application sites. In this study, the dissipation of ( R )- and ( S )-dichlorprop in an agricultural soil was investigated. We found that the dissipation rate of ( S )-dichlorprop was higher than that of ( R )-dichlorprop in an agricultural soil. Although the influences of different enantiomers of dichlorprop on soil bacterial community were not different, Sphingobium was significantly enriched in the ( S )-dichlorprop-treated soil as compared to ( R )-dichlorprop, indicating that Sphingobium species played important roles in the dissipation of ( S )-dichlorprop. Furthermore, a bacterial consortium containing Sphingobium sp. strain SP-2 (enantioselectively transforming ( S )-dichlorprop to 2,4-dichlorophenol) and Sphingopyxis sp. strain DP-21 (mineralizing 2,4-dichlorophenol), which synergistically mineralized the ( S )-enantiomer of dichlorprop, was isolated from the agricultural soil. Bioaugmentation with the in-situ isolated consortium (strains SP-2 and DP-21) resulted in the enhanced removal of the non-herbicidal ( S )-dichlorprop from the soil and in the adaptation of the inoculated degrading strains. This study offers new insights into the enhanced bioremediation of the non-herbicidal ( S )-dichlorprop contaminated soils while simultaneously ensuring environmental safety and crop yield.
研究领域:
环境科学
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微生物学
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土壤学
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生物修复
✓ 已验证
DOI
高影响因子
INTERNATIONAL BIODETERIORATION & BIODEGRADATION
·
2022
·
IF 4.907
Long Zhang,Man Song,Zhenbo Mao,Yuan Liu,Feng Li,Jiandong Jiang,Kai Chen
Dichlorprop [( R , S )-2-(2,4-dichlorophenoxy)propanoic acid], a chiral herbicide belonging to phenoxyalkanoic acid herbicides, is extensively used around the world, and is frequently detected in various habitats. Although ( S )-dichlorprop has no herbicidal activity, its toxicity and ecological risk are higher than ( R )-dichlorprop. In our previous studies, the isolated strain Sphingopyxis sp. DBS4 was confirmed to mineralize both ( R )-dichlorprop and ( S )-dichlorprop, but the key genes responsible for the initial degradation of ( R )-/( S )-dichlorprop were still unclear. Here, based on genome sequencing and enzyme purification , a new dioxygenase gene, spoA , responsible for the initial transformation of ( S )-dichlorprop to 2,4-dichlorophenol and pyruvate was cloned from the rac -dichlorprop-utilizing strain of Sphingopyxis sp. DBS4. SpoA, an α -ketoglutarate-dependent dioxygenase, exhibited low amino acid sequence identity to the reported ( S )-dichlorprop-transforming dioxygenase SdpA (34.8%), and showed enantioselective activity toward ( S )-enantiomers of dichlorprop and mecoprop, but no activity toward the corresponding ( R )-enantiomers. The K m value of SpoA for ( S )-dichlorprop was 134.3 μM, and the k cat / K m was determined to be 7.5 × 10 −2 μM −1 s −1 . Molecular docking and site-directed mutagenesis showed that two residues of SdpA, Lys101 and Asp119, are the key sites for the enantioselective transformation of ( S )-dichlorprop. Our study identifies a new dioxygenase for the enantioselective transformation of ( S )-dichlorprop and deepens our understanding of the microbial catabolism of chiral phenoxyalkanoic acid herbicides.
研究领域:
环境微生物学
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酶学
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生物降解
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产品关联
DOI
高影响因子
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
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2021
·Vol. 87
·期 22
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IF 4.792
Shunli Hu,Guiping Liu,Long Zhang,Yufeng Gan,Baozhan Wang,Shiri Freilich,Jiandong Jiang
rac-Dichlorprop, a commonly used phenoxyalkanoic acid herbicide, is frequently detected in environments and poses threats to environmental safety and human health. Microbial consortia are thought to play key roles in rac-dichlorprop degradation. However, the compositions of the microbial consortia involved in rac-dichlorprop degradation remain largely unknown. In this study, DNA stable isotope probing (SIP) and metagenomic analysis were integrated to reveal the key microbial consortium responsible for rac-dichlorprop degradation in a rac-dichlorprop-degrading enrichment. OTU340 (Sphingobium sp.) and OTU348 (Sphingopyxis sp.) were significantly enriched in the rac-[13C]dichlorprop-labeled heavy DNA fractions. A rac-dichlorprop degrader, Sphingobium sp. strain L3, was isolated from the enrichment by a traditional enrichment method but with additional supplementation of the antibiotic ciprofloxacin, which was instructed by metagenomic analysis of the associations between rac-dichlorprop degraders and antibiotic resistance genes. As revealed by functional profiling of the metagenomes of the heavy DNA, the genes rdpA and sdpA, involved in the initial degradation of the (R)- and (S)-enantiomers of dichlorprop, respectively, were mostly taxonomically assigned to Sphingobium species, indicating that Sphingopyxis species might harbor novel dichlorprop-degrading genes. In addition, taxonomically diverse bacterial genera such as Dyella, Sphingomonas, Pseudomonas, and Achromobacter were presumed to synergistically cooperate with the key degraders Sphingobium/Sphingopyxis for enhanced degradation of rac-dichlorprop.IMPORTANCE Understanding of the key microbial consortium involved in the degradation of the phenoxyalkanoic acid herbicide rac-dichlorprop is pivotal for design of synergistic consortia used for enhanced bioremediation of herbicide-contaminated sites. However, the composition of the microbial consortium and the interactions between community members during the biodegradation of rac-dichlorprop are unclear. In this study, DNA-SIP and metagenomic analysis were integrated to reveal that the metabolite 2,4-dichlorophenol degraders Dyella, Sphingomonas, Pseudomonas, and Achromobacter synergistically cooperated with the key degraders Sphingobium/Sphingopyxis for enhanced degradation of rac-dichlorprop. Our study provides new insights into the synergistic degradation of rac-dichlorprop at the community level and implies the existence of novel degrading genes for rac-dichlorprop in nature.
研究领域:
环境微生物学
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基因组学
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生物修复
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）