Biodegradation Pathway and Detoxification of β-cyfluthrin by the Bacterial Consortium and Its Bacterial Community Structure

Abstract

In the process of microbial degradation of pyrethroid pesticides, the synergistic effect of the microbial community is more conducive to the complete degradation of toxic compounds than a single strain. At present, the degradation pathway of pyrethroids in a single strain has been well revealed, but the synergistic metabolism at the community level has not been well explained. This study elucidated the bacterial community succession, metabolic pathway, and phytotoxicity assessment during βcyfluthrin biodegradation by a novel bacterial consortium enriched from contaminated soil. The results showed that the half-life of βcyfluthrin at different initial concentrations of 0.25, 0.5, 0.75, and 1.0 mg mL −1 were 4. 16, 7.34, 12.81, and 22.73 days, respectively. Enterobacter was involved in β-cyfluthrin degradation metabolism in the initial stage, and other bacterial genera (Microbacterium, Ochrobactrum, Pseudomonas, Hyphomicrobiaceae, Achromobacter, etc.) significantly contribute to the degradation of intermediate metabolites in the later stages. Functional gene prediction and metabolite analysis showed that xenobiotic biodegradation and metabolism, especially benzoate degradation and metabolism by cytochrome P450 were the major means of β-cyfluthrin degradation. Further, two degradation pathways of β-cyfluthrin were proposed, which were mainly ester hydrolysis and oxidation to degrade β-cyfluthrin through the production of carboxylesterase and oxidoreductase. In addition, the inoculated bacterial consortium could degrade β-cyfluthrin residues in water and soil and reduce its phytotoxicity in Medicago sativa. Hence, this novel bacterial consortium has important application in the remediation environments polluted by β-cyfluthrin.

Effects of Free or Immobilized Bacterium Stenotrophomonas acidaminiphila Y4B on Glyphosate Degradation Performance and Indigenous Microbial Community Structure

“…Second, the microbial community structure was changed to facilitate glyphosate degradation as the inoculation with strain Y4B. Proteobacteria have been found to substantially increase in glyphosate and other pollutants in contaminated soil than those in the untreated control. , …”

Rapid Biodegradation of the Organophosphorus Insecticide Acephate by a Novel Strain Burkholderia sp. A11 and Its Impact on the Structure of the Indigenous Microbial Community

“…A total of 5 g of the sludge sample was placed in MSM1 containing 50 mL of acephate, and then, the mixture was incubated in a shaker at 200 rpm and 30 °C for 5 days; 4 mL of the enriched cultures was placed in fresh MSM1 containing 100 mg·L –1 under the same conditions. Subsequently, the enriched culture was added to the MSM1 in higher concentrations (200, 400, or 800 mg·L –1 ) for culture using the same procedure. , The resulting medium was continuously diluted and coated on an MSM1 agar (2%) plate containing 100 mg·L –1 , which was cultured at 30 °C for 2 days. After the single bacteria were isolated, they could be used for the degradation experiment.…”

Cellular Response and Molecular Mechanism of Glyphosate Degradation by Chryseobacterium sp. Y16C

“…23−26 It is worth noting that the transformation and degradation of environmental pollutants by microorganisms mainly rely on the catalysis of various enzymes. 4,27,28 The identification and characterization of these degrading enzymes will be of great significance for the treatment of environmental pollution, the removal of pesticide residues in agricultural products, and the elucidation of the mechanism of microbial degradation. 29−31 Current reports on the degradation of glyphosate mainly focus on the screening of high-efficiency degrading bacteria, optimizing culture conditions, identifying metabolic pathways, and applying glyphosate-resistant transgenic crops.…”

“…In the natural environment, especially in soils where glyphosate has been applied for a long time, a wide variety of strains are observed that can tolerate or degrade glyphosate. Therefore, screening microbial strains capable of degrading toxic substances from polluted environments has gradually become a new approach and strategy for the development of microbial resources. , At present, an increasing number of reports has focused on the degradation of glyphosate by microorganisms, and some microorganisms with the ability to degrade glyphosate have been gradually isolated and identified, such as Pseudomonas , Alcaligenes , Arthrobacter , Penicillium , Candida krusei s , Yarrowia lipolytica , Aspergillus niger, and Rhodotorula mucilaginose . − It is worth noting that the transformation and degradation of environmental pollutants by microorganisms mainly rely on the catalysis of various enzymes. ,, The identification and characterization of these degrading enzymes will be of great significance for the treatment of environmental pollution, the removal of pesticide residues in agricultural products, and the elucidation of the mechanism of microbial degradation. − Current reports on the degradation of glyphosate mainly focus on the screening of high-efficiency degrading bacteria, optimizing culture conditions, identifying metabolic pathways, and applying glyphosate-resistant transgenic crops. ,,− However, relatively few reports have investigated glyphosate-degrading enzymes and associated molecular mechanisms . At present, four main enzymes have been found to be involved in microbial degradation of glyphosate, namely, glyphosate oxidoreductase (GOX), glycine oxidase (GO), glyphosate C–P lyase, and glyphosate N -acetyltransferase (GAT). ,,, Both GOX and GO can catalyze the degradation of glyphosate to aminomethylphosphonic acid (AMPA) and glyoxylate, although their catalytic mechanisms are different.…”