A novel alkalizing strain Enterobacter sp.LYX-2 that could resist 400 mg/L Cd was isolated from Cd-contaminated soil,which immobilized 96.05%Cd^(2+)from medium.Cd distribution analysis demonstrated that more than half...A novel alkalizing strain Enterobacter sp.LYX-2 that could resist 400 mg/L Cd was isolated from Cd-contaminated soil,which immobilized 96.05%Cd^(2+)from medium.Cd distribution analysis demonstrated that more than half of the Cd^(2+)was converted into extracellular precipitated Cd through mobilization of the alkali-producing mechanism by the strain LYX-2,achieving the high immobilization efficiency of Cd^(2+).Biosorption experiments revealed that strain LYX-2 had superior biosorption capacity of 48.28 mg/g for Cd.Pot experiments with Brassica rapa L.were performed with and without strain LYX-2.Compared to control,15.92%bioavailable Cd was converted to non-bioavailable Cd and Cd content in aboveground vegetables was decreased by 37.10%with addition of strain LYX-2.Available Cd was mainly immobilized through extracellular precipitation,cell-surface biosorption and intracellular accumulation of strain LYX-2,which was investigated through Cd distribution,Scanning Electron Microscope and Energy-Dispersive X-ray Spectroscopy(SEM-EDS),Fourier Transform Infrared Spectroscopy(FT-IR),X-ray Photoelectron Spectroscopy(XPS)and Transmission Electron Microscopy(TEM)analysis.In addition,the application of strain LYX-2 significantly promoted the growth of vegetables about 2.4-fold.Above results indicated that highly Cd-resistant alkalizing strain LYX-2,as a novel microbial passivator,had excellent ability and reuse value to achieve the remediation of Cd-contaminated soil coupled with safe production of vegetables simultaneously.展开更多
To determine the occurrence of Enterobacter sakazakii and other Enerobateriaceae in commercial powdered infant formula (PIF), 185 packages of PIF from different manufacturers, supermarkets and drug-stores in Abidjan w...To determine the occurrence of Enterobacter sakazakii and other Enerobateriaceae in commercial powdered infant formula (PIF), 185 packages of PIF from different manufacturers, supermarkets and drug-stores in Abidjan were analyzed. Ten g of sample was homogenized in 90 ml of buffered peptone water (PBW, Biorad, Paris) for further studies. Enterobacteriaceae (coliforms) were enumerated according to French Association of Standardization methods. E. sakazakii was detected according to Kandhai’s method. Bacteria were identified using API20 system. Thirty-eight samples (20.5%) were positive for Enterobacteriaceae. Twenty-four samples (13%) yielded Enterobacter sakazakii. Other Enterobacteriaceae isolated included Pantoea spp. 21 (11.5%), Klebsiella pneumoniae subsp. Pneumonia 8 (4.3%), Citrobacter diversus 1 (0.5%), Citrobacter freundii 1 (0.5%), Enterobacter cloacae 1 (0.5%), Salmonella reading 1 (0.5%), Serratia ficara 1 (0.5%) Serratia odorifera 1 (0.5%). This study is the first report to describe the contamination of PIF from Abidjan with E. sakazakii and several other Enterobacteriaceae that could be opportunistic pathogens. Therefore, well-controlled studies need to be conducted to assess the extent of risk associated with contaminated PIF for infants in Abidjan.展开更多
基金supported by the National Key Research and Development Program of China (No.2018YFC1800403)the National Natural Science Foundation of China (No.41571226)the Scientific Research Fund of Zhejiang University (No.XY2021020)。
文摘A novel alkalizing strain Enterobacter sp.LYX-2 that could resist 400 mg/L Cd was isolated from Cd-contaminated soil,which immobilized 96.05%Cd^(2+)from medium.Cd distribution analysis demonstrated that more than half of the Cd^(2+)was converted into extracellular precipitated Cd through mobilization of the alkali-producing mechanism by the strain LYX-2,achieving the high immobilization efficiency of Cd^(2+).Biosorption experiments revealed that strain LYX-2 had superior biosorption capacity of 48.28 mg/g for Cd.Pot experiments with Brassica rapa L.were performed with and without strain LYX-2.Compared to control,15.92%bioavailable Cd was converted to non-bioavailable Cd and Cd content in aboveground vegetables was decreased by 37.10%with addition of strain LYX-2.Available Cd was mainly immobilized through extracellular precipitation,cell-surface biosorption and intracellular accumulation of strain LYX-2,which was investigated through Cd distribution,Scanning Electron Microscope and Energy-Dispersive X-ray Spectroscopy(SEM-EDS),Fourier Transform Infrared Spectroscopy(FT-IR),X-ray Photoelectron Spectroscopy(XPS)and Transmission Electron Microscopy(TEM)analysis.In addition,the application of strain LYX-2 significantly promoted the growth of vegetables about 2.4-fold.Above results indicated that highly Cd-resistant alkalizing strain LYX-2,as a novel microbial passivator,had excellent ability and reuse value to achieve the remediation of Cd-contaminated soil coupled with safe production of vegetables simultaneously.
文摘To determine the occurrence of Enterobacter sakazakii and other Enerobateriaceae in commercial powdered infant formula (PIF), 185 packages of PIF from different manufacturers, supermarkets and drug-stores in Abidjan were analyzed. Ten g of sample was homogenized in 90 ml of buffered peptone water (PBW, Biorad, Paris) for further studies. Enterobacteriaceae (coliforms) were enumerated according to French Association of Standardization methods. E. sakazakii was detected according to Kandhai’s method. Bacteria were identified using API20 system. Thirty-eight samples (20.5%) were positive for Enterobacteriaceae. Twenty-four samples (13%) yielded Enterobacter sakazakii. Other Enterobacteriaceae isolated included Pantoea spp. 21 (11.5%), Klebsiella pneumoniae subsp. Pneumonia 8 (4.3%), Citrobacter diversus 1 (0.5%), Citrobacter freundii 1 (0.5%), Enterobacter cloacae 1 (0.5%), Salmonella reading 1 (0.5%), Serratia ficara 1 (0.5%) Serratia odorifera 1 (0.5%). This study is the first report to describe the contamination of PIF from Abidjan with E. sakazakii and several other Enterobacteriaceae that could be opportunistic pathogens. Therefore, well-controlled studies need to be conducted to assess the extent of risk associated with contaminated PIF for infants in Abidjan.
