title: Bioremediation potential of glyphosate-degrading Pseudomonas spp. strains isolated from contaminated soil.
abstract: Bacterial strains capable of utilizing glyphosate as the sole carbon source were isolated from contaminated soil by the enrichment culture method and identified based on partial 16S rRNA gene sequence analysis. Pseudomonas spp. strains GA07, GA09 and GC04 demonstrated the best degradation capabilities towards glyphosate and were used for the laboratory experiments of glyphosate bioremediation. Inoculating glyphosate-treated soil samples with these three strains resulted in a 2-3 times higher rate of glyphosate removal than that in non-inoculated soil. The degradation kinetics was found to follow a first-order model with regression values greater than 0.96. Cell numbers of the introduced bacteria decreased from 4.4 × 10(6) CFU/g to 3.4-6.7 × 10(5) CFU/g dry soil within 18 days of inoculation. Due to the intense degradation of glyphosate, the total dehydrogenase activity of the soil microbial community increased by 21.2-25.6%. Analysis of glyphosate degradation products in cell-free extracts showed that glyphosate breakdown in strain GA09 was catalyzed both by C-P lyase and glyphosate oxidoreductase. Strains GA07 and GC04 degraded glyphosate only via glyphosate oxidoreductase, but no further metabolite was detected. These results highlight the potential of the isolated bacteria to be used in the bioremediation of GP-contaminated soils.
authors.affiliation: Key Laboratory of Integrated Pest Management on Crops in Southwest, Ministry of Agriculture, Institute of Plant Protection, Sichuan Academy of Agricultural Science.
authors.forename: Haoyu
authors.initials: H
authors.lastname: Zhao
authors.forename: Ke
authors.initials: K
authors.lastname: Tao
authors.forename: Jianyi
authors.initials: J
authors.lastname: Zhu
authors.forename: Shengnan
authors.initials: S
authors.lastname: Liu
authors.forename: Han
authors.initials: H
authors.lastname: Gao
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Zhou
mesh_terms: D001673:Biodegradation, Environmental; D002244:Carbon / Q000378:metabolism; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005998:Glycine / Q000031:analogs & derivatives* / Q000378:metabolism; D008190:Lyases / Q000378:metabolism; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000378:metabolism; D010802:Phylogeny; D011549:Pseudomonas / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D000097797:Glyphosate
chemical_list: D002244:Carbon; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005998:Glycine; D008190:Lyases; D010088:Oxidoreductases; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; D000097797:Glyphosate; C051328:carbon-phosphorus lyase