Strain EDP3 was isolated from an industrial-activated sludge. It belonged to the gamma group of Pro-teobacteria with an identity of 97.0% to Acinetobacter calcoaceticus according to the 16S rRNA gene sequences. It can...Strain EDP3 was isolated from an industrial-activated sludge. It belonged to the gamma group of Pro-teobacteria with an identity of 97.0% to Acinetobacter calcoaceticus according to the 16S rRNA gene sequences. It can tolerate up to 1000mg·L^-1 phenol at room temperature with a much longer lag phase. This indicates that higher phenol concentration has induced some physiological and genotypic changes in the bacterium. The aim of this study is, therefore, to investigate these responses to phenol concentration variations in strain EDP3. Proteome analysis is conducted by means of a two-dimensional polyacrylamide gel electrophoresis (2D PAGE) and matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) was conducted to obtain a deeper insight into the adaptive responses inside the bacterium. Comparative analysis of the proteome profiles of strain EDP3. grown in 400mg·L^-1 and 1000mg·L^-1 phenol allowed us to identify that among all the proteins up-regulated under the higher phenol concentration, oxidative stress proteins were dominant. The synthesis of a heat shock protein, 60000 chaperonin GroEL, was also amplified. In addition, the expression of one membrane protein, adenosine 5'-triphosphate (ATP)-binding cassette (ABC) type sugar transporter, was found up-regulated. The inhibition of adenosine 5'-triphosphate (ATP) and RNA/protein synthesis was also observed.展开更多
Isolation of new bacterial strains and recognition of their metabolic activities are highly desirable for sustainability of natural ecosystems. Biodegradation of dimethyl phthalate (DMP) under anoxic conditions has ...Isolation of new bacterial strains and recognition of their metabolic activities are highly desirable for sustainability of natural ecosystems. Biodegradation of dimethyl phthalate (DMP) under anoxic conditions has been shown to occur as a series of sequential steps using strain CW-1 isolated from digested sludge of Sibao Wastewater Treatment Plant in Hangzhou, China. The microbial colony on LB medium was yellowish, 3-5 mm in diameter, convex in the center, and embedded in mucous externally. The individual cells of strain CW-1 are irregular rods, measuring (0.6-0.7)×(0.9-1.0) pm, V-shaped, with clubbed ends, Gram positive and without any filaments. 16S rDNA ( 1438 bp) sequence analysis showed that the strain was related to Arthrobacter sp. CW-1 and can degrade PAEs utilizing nitrate as electron acceptor, but cannot mineralize DMP completely. The degradation pathway was recommended as: dimethyl phthalate (DMP)→monomethyl phthalate (MMP)--,phthalic acid (PA). DMP biodegradation was a first order reaction with degradation rate constant of 0.3033 d 1 and half-life 2.25 d. The DMP conversion to PA by CW-1 could be described by using sequential kinetic model.展开更多
A novel phenanthrene (PHE)-degrading strain named as Sphingomonas sp.GF2B was isolated and identified from a farmland soil.Effects of a synthetic surfactant (Tween-80) and a rhamnolipid biosurfactant on PHE degradatio...A novel phenanthrene (PHE)-degrading strain named as Sphingomonas sp.GF2B was isolated and identified from a farmland soil.Effects of a synthetic surfactant (Tween-80) and a rhamnolipid biosurfactant on PHE degradation by Sphin- gomonas sp.GF2B were investigated at different concentrations of the surfactants.The results showed that Sphingomonas sp.GF2B was able to mineralize up to 83.6% of PHE within 10 days without addition of surfactants.The addition of Tween-80 to the reaction medium inhibited greatly PHE biodegradation,with only 33.5% of PHE degraded.However,the biosurfactant facilitated PHE biodegradation,with up to 99.5% of PHE degraded.The preferential utilization of PHE as a carbon source and the enhanced solubility of PHE by the biosurfactant were likely responsible for the higher biodegra- dation efficiency of PHE in the presence of the biosurfactant.Therefore,it could be concluded that the application of the biosurfactant to PHE-contaminated soils was perhaps a feasible way to facilitate the PHE biodegradation.展开更多
A bacterial strain, Arthrobacter oxydans (B4), capable of degrading benzo[a]pyrene (BaP) in water body, was isolated from a polycyclic aromatic hydrocarbons-contaminated site. Effects of different factors, such as...A bacterial strain, Arthrobacter oxydans (B4), capable of degrading benzo[a]pyrene (BaP) in water body, was isolated from a polycyclic aromatic hydrocarbons-contaminated site. Effects of different factors, such as reaction time, pH value, temperature and organic nutrients, on BaP biodegradation by the strain B4 were studied. After 5 d treatment, the concentration of BaP in mineral salts medium was reduced to 0.318 mg L-1, compared to the initial concentration of 1.000 mg L-1. There was a process of acid formation during the degradation with pH falling from initial 7.01 to 4.61 at 5 d, so keeping the water body under slightly alkaline condition was propitious to BaP degradation. Strain B4 efficiently degraded BaP at 20 to 37 ~C with addition of organic nutrients. The biodegradation and transformation of BaP mainly occurred on cell surfaces, and extracellular secretions played an important role in these processes. Fourier transform infrared spectroscopy and gas chromatograph-mass spectrometer analyses of metabolites showed that ring cleavage occurred in the BaP degradation process and the resulting metabolically utilizable substrates were generated as sole carbon sources for B4 growth. Furthermore, mineralization extent of metabolites was verified by determining the total organic carbon and inorganic carbon in the degradation system.展开更多
文摘Strain EDP3 was isolated from an industrial-activated sludge. It belonged to the gamma group of Pro-teobacteria with an identity of 97.0% to Acinetobacter calcoaceticus according to the 16S rRNA gene sequences. It can tolerate up to 1000mg·L^-1 phenol at room temperature with a much longer lag phase. This indicates that higher phenol concentration has induced some physiological and genotypic changes in the bacterium. The aim of this study is, therefore, to investigate these responses to phenol concentration variations in strain EDP3. Proteome analysis is conducted by means of a two-dimensional polyacrylamide gel electrophoresis (2D PAGE) and matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) was conducted to obtain a deeper insight into the adaptive responses inside the bacterium. Comparative analysis of the proteome profiles of strain EDP3. grown in 400mg·L^-1 and 1000mg·L^-1 phenol allowed us to identify that among all the proteins up-regulated under the higher phenol concentration, oxidative stress proteins were dominant. The synthesis of a heat shock protein, 60000 chaperonin GroEL, was also amplified. In addition, the expression of one membrane protein, adenosine 5'-triphosphate (ATP)-binding cassette (ABC) type sugar transporter, was found up-regulated. The inhibition of adenosine 5'-triphosphate (ATP) and RNA/protein synthesis was also observed.
文摘Isolation of new bacterial strains and recognition of their metabolic activities are highly desirable for sustainability of natural ecosystems. Biodegradation of dimethyl phthalate (DMP) under anoxic conditions has been shown to occur as a series of sequential steps using strain CW-1 isolated from digested sludge of Sibao Wastewater Treatment Plant in Hangzhou, China. The microbial colony on LB medium was yellowish, 3-5 mm in diameter, convex in the center, and embedded in mucous externally. The individual cells of strain CW-1 are irregular rods, measuring (0.6-0.7)×(0.9-1.0) pm, V-shaped, with clubbed ends, Gram positive and without any filaments. 16S rDNA ( 1438 bp) sequence analysis showed that the strain was related to Arthrobacter sp. CW-1 and can degrade PAEs utilizing nitrate as electron acceptor, but cannot mineralize DMP completely. The degradation pathway was recommended as: dimethyl phthalate (DMP)→monomethyl phthalate (MMP)--,phthalic acid (PA). DMP biodegradation was a first order reaction with degradation rate constant of 0.3033 d 1 and half-life 2.25 d. The DMP conversion to PA by CW-1 could be described by using sequential kinetic model.
基金Supported by the National Natural Science Foundation of China (No. 20377024)the National High Technology Research and Development Program (863 Program) of China (Nos. 2007AA061101 and 2009AA063103)
文摘A novel phenanthrene (PHE)-degrading strain named as Sphingomonas sp.GF2B was isolated and identified from a farmland soil.Effects of a synthetic surfactant (Tween-80) and a rhamnolipid biosurfactant on PHE degradation by Sphin- gomonas sp.GF2B were investigated at different concentrations of the surfactants.The results showed that Sphingomonas sp.GF2B was able to mineralize up to 83.6% of PHE within 10 days without addition of surfactants.The addition of Tween-80 to the reaction medium inhibited greatly PHE biodegradation,with only 33.5% of PHE degraded.However,the biosurfactant facilitated PHE biodegradation,with up to 99.5% of PHE degraded.The preferential utilization of PHE as a carbon source and the enhanced solubility of PHE by the biosurfactant were likely responsible for the higher biodegra- dation efficiency of PHE in the presence of the biosurfactant.Therefore,it could be concluded that the application of the biosurfactant to PHE-contaminated soils was perhaps a feasible way to facilitate the PHE biodegradation.
基金Supported by the National Natural Science Foundation of China(Nos.50978122 and U0933002)
文摘A bacterial strain, Arthrobacter oxydans (B4), capable of degrading benzo[a]pyrene (BaP) in water body, was isolated from a polycyclic aromatic hydrocarbons-contaminated site. Effects of different factors, such as reaction time, pH value, temperature and organic nutrients, on BaP biodegradation by the strain B4 were studied. After 5 d treatment, the concentration of BaP in mineral salts medium was reduced to 0.318 mg L-1, compared to the initial concentration of 1.000 mg L-1. There was a process of acid formation during the degradation with pH falling from initial 7.01 to 4.61 at 5 d, so keeping the water body under slightly alkaline condition was propitious to BaP degradation. Strain B4 efficiently degraded BaP at 20 to 37 ~C with addition of organic nutrients. The biodegradation and transformation of BaP mainly occurred on cell surfaces, and extracellular secretions played an important role in these processes. Fourier transform infrared spectroscopy and gas chromatograph-mass spectrometer analyses of metabolites showed that ring cleavage occurred in the BaP degradation process and the resulting metabolically utilizable substrates were generated as sole carbon sources for B4 growth. Furthermore, mineralization extent of metabolites was verified by determining the total organic carbon and inorganic carbon in the degradation system.