An extracellular NP-degrading enzyme secreted by Bacillus cereus.Frankland was purified to homogeneity by a combination of ammonium sulfate precipitation,Phenyl-Sepharose hydrophobic-interaction chromatography and DEA...An extracellular NP-degrading enzyme secreted by Bacillus cereus.Frankland was purified to homogeneity by a combination of ammonium sulfate precipitation,Phenyl-Sepharose hydrophobic-interaction chromatography and DEAE anion-exchange chromatography.On SDS（sodium dodecyl sulfate）-polyacrylamide gel electrophoresis analysis,the purified enzyme showed a relative molecular mass of 58.3 kDa.The depolymerzation of subunits was accompanied with the loss of NP-degrading enzyme activity,and removing denaturing factors by dialysis could restore the dimer structure and enzymatic activity.The enzyme had an isoelectric point of 5.5 and an optimal temperature of 60℃,and was the most active at pH 6.0.The enzymatic activity was stable at pH 4-8 and inhibited by Cu2＋.TenN-terminal amino acids were determined to be ASVNSIKIGY,demonstrating that the purified enzyme was a novel one.The hydrolysis pattern of the purified enzyme indicated that the NP-degrading enzyme was an endo NP-degrading enzyme.The extraordinary thermo-stability provided the enzyme with a good prospect to be used as a new tool for clean-production process for textile industry.展开更多
Here reproduction and death toxicity data were selected for 4-nonylphenol based on endocrine disrupting properties of the re- productive system. Assessment factor （AF） and species sensitivity distribution （SSD） cu...Here reproduction and death toxicity data were selected for 4-nonylphenol based on endocrine disrupting properties of the re- productive system. Assessment factor （AF） and species sensitivity distribution （SSD） curve were employed to derive criteria maximum concentration （CMC） and criteria continuous concentration （CCC） of three different 4-nonylphenols for protection of aquatic life. The results showed that the CMC and CCC based on SSD method and death toxicity data for three different 4-nonylphenols （CAS No： 104405, 25154523, 84852163） were 26.7, 13.6, 3.84μg L-1 and 8.86, 2.21, 0.97 μg L-1, respectively. Based on SSD and reproductive toxicity data, the CCC values of different 4-nonylphenols （CAS No： 104405, 25154523） were 1.59 and 1.34μg L-l, respectively. The CCC values obtained by the AF for three different 4-nonylphenol （CAS No： 104405, 25154523, 84852163） were 0.165, 1.03, 0.74 μg L -1 and 0.5, 0.5, 0.1μg L-1, respectively, based on death toxicity data and re- productive toxicity data. The CCC values obtained by AF were all lower than the corresponding criteria values obtained by SSD, and the CCC values based on reproductive toxicity data were less than those based on the death toxicity data. This study provides a useful method for deriving water quality criteria for endocrine disruptors.展开更多
Trace organic contaminants (TOCs) correspond to a broad range of molecules generated either directly or indirectly by human activity. Even though TOCs are found at low concentrations in the environment, they often acc...Trace organic contaminants (TOCs) correspond to a broad range of molecules generated either directly or indirectly by human activity. Even though TOCs are found at low concentrations in the environment, they often accumulate by biomagnification and bioaccumulation into biological organisms and cause irreversible damages in biological systems through direct or indirect toxic effects such as endocrine disruption and tumour initiation. This manuscript presents the main findings of over fifteen years of research focusing on biological removal of various TOCs found in sewage sludge from urban treatment plants. A special focus of the research was made on microbial processes in complex anaerobic ecosystems. Four families of compounds mostly retrieved in urban plants were studied: the polycyclic aromatic hydrocarbons (PAHs), the polychlorobiphenyls (PCBs), the phthalic acid esters (PAEs), and the nonylphenol ethoxylates (NPEs). It was observed that the microbial capability for removing low amounts of TOCs required a long adaptation time and was often limited by the bioavailability of these compounds. In fact, the overall biodegradation resulted from the numerous interactions existing between the matrix (organic matter) and the microbial ecosystems according to the physico-chemical sorption properties of these compounds. Mechanistic aspects were also tackled in depth and specific models were developed for better understanding the network of interactions between TOCs, microorganisms, and organic matter. These findings could be extrapolated to other ecosystems such as soils and sediments. Finally, it was shown that microbial cometabolism was essential for TOC removal, and the concept of bioavailability was not only dependent on the nature, the level, and the sorption properties of TOCs but was also strongly dependent on the nature and the concentration of the sludge organic matter. Specific parameters were proposed for better evaluating the fate of TOCs in microbial anaerobic processes and technological solutions for efficient removal of these compounds were also proposed.展开更多
基金Supported by the Fund of Open Subject of Key Lab of Biogeology and Environmental Geology of Ministry of Education(BGEG1006)
文摘An extracellular NP-degrading enzyme secreted by Bacillus cereus.Frankland was purified to homogeneity by a combination of ammonium sulfate precipitation,Phenyl-Sepharose hydrophobic-interaction chromatography and DEAE anion-exchange chromatography.On SDS（sodium dodecyl sulfate）-polyacrylamide gel electrophoresis analysis,the purified enzyme showed a relative molecular mass of 58.3 kDa.The depolymerzation of subunits was accompanied with the loss of NP-degrading enzyme activity,and removing denaturing factors by dialysis could restore the dimer structure and enzymatic activity.The enzyme had an isoelectric point of 5.5 and an optimal temperature of 60℃,and was the most active at pH 6.0.The enzymatic activity was stable at pH 4-8 and inhibited by Cu2＋.TenN-terminal amino acids were determined to be ASVNSIKIGY,demonstrating that the purified enzyme was a novel one.The hydrolysis pattern of the purified enzyme indicated that the NP-degrading enzyme was an endo NP-degrading enzyme.The extraordinary thermo-stability provided the enzyme with a good prospect to be used as a new tool for clean-production process for textile industry.
基金supported by National Key Basic Research Development Program (Grant No. 2008CB418205)Major Project of Water Pollution Control and Management (Grant No. 2009ZX07528-002-04)+1 种基金Outstanding Young Teacher Research and Special Projects (Grant No. Shu10040)Shanghai Leading Academic Discipline (Grant No. S30109)
文摘Here reproduction and death toxicity data were selected for 4-nonylphenol based on endocrine disrupting properties of the re- productive system. Assessment factor （AF） and species sensitivity distribution （SSD） curve were employed to derive criteria maximum concentration （CMC） and criteria continuous concentration （CCC） of three different 4-nonylphenols for protection of aquatic life. The results showed that the CMC and CCC based on SSD method and death toxicity data for three different 4-nonylphenols （CAS No： 104405, 25154523, 84852163） were 26.7, 13.6, 3.84μg L-1 and 8.86, 2.21, 0.97 μg L-1, respectively. Based on SSD and reproductive toxicity data, the CCC values of different 4-nonylphenols （CAS No： 104405, 25154523） were 1.59 and 1.34μg L-l, respectively. The CCC values obtained by the AF for three different 4-nonylphenol （CAS No： 104405, 25154523, 84852163） were 0.165, 1.03, 0.74 μg L -1 and 0.5, 0.5, 0.1μg L-1, respectively, based on death toxicity data and re- productive toxicity data. The CCC values obtained by AF were all lower than the corresponding criteria values obtained by SSD, and the CCC values based on reproductive toxicity data were less than those based on the death toxicity data. This study provides a useful method for deriving water quality criteria for endocrine disruptors.
基金Supported by the French Agency for Environment and Energy(ADEME) (No.0075033)the Ph.D.Grants and the Marie-Curie Fellowship of the European Union(No.MEIF-CT-2003-500956)
文摘Trace organic contaminants (TOCs) correspond to a broad range of molecules generated either directly or indirectly by human activity. Even though TOCs are found at low concentrations in the environment, they often accumulate by biomagnification and bioaccumulation into biological organisms and cause irreversible damages in biological systems through direct or indirect toxic effects such as endocrine disruption and tumour initiation. This manuscript presents the main findings of over fifteen years of research focusing on biological removal of various TOCs found in sewage sludge from urban treatment plants. A special focus of the research was made on microbial processes in complex anaerobic ecosystems. Four families of compounds mostly retrieved in urban plants were studied: the polycyclic aromatic hydrocarbons (PAHs), the polychlorobiphenyls (PCBs), the phthalic acid esters (PAEs), and the nonylphenol ethoxylates (NPEs). It was observed that the microbial capability for removing low amounts of TOCs required a long adaptation time and was often limited by the bioavailability of these compounds. In fact, the overall biodegradation resulted from the numerous interactions existing between the matrix (organic matter) and the microbial ecosystems according to the physico-chemical sorption properties of these compounds. Mechanistic aspects were also tackled in depth and specific models were developed for better understanding the network of interactions between TOCs, microorganisms, and organic matter. These findings could be extrapolated to other ecosystems such as soils and sediments. Finally, it was shown that microbial cometabolism was essential for TOC removal, and the concept of bioavailability was not only dependent on the nature, the level, and the sorption properties of TOCs but was also strongly dependent on the nature and the concentration of the sludge organic matter. Specific parameters were proposed for better evaluating the fate of TOCs in microbial anaerobic processes and technological solutions for efficient removal of these compounds were also proposed.
