Three strains of Gram-negative bacteria capable of removing geosmin from drinking water were isolated from biologically active carbon and identified to be Chryseobacterium sp., Sinorhizobium sp. and Stenotrophomonas s...Three strains of Gram-negative bacteria capable of removing geosmin from drinking water were isolated from biologically active carbon and identified to be Chryseobacterium sp., Sinorhizobium sp. and Stenotrophomonas sp. based on physio-biochemistry analysis and 16S rRNA gene sequence analysis. Removal efficiencies of 2 mg/L geosmin in mineral salts medium were 84.0%, 80.2% and 74.4% for Chryxeobacterium sp., Sinorhizobium sp. and Stenotrophomonas sp., respectively, while removal efficiencies of 560 ng/L geosmin in filter influent were 84.8%, 82.3% and 82.5%, respectively. The biodegradation of geosmin was determined to be a pseudo first-order reaction, with rate constants at 2 mg/L and 560 ng/L being 0.097 and 0.086 day-1, 0.089 and 0.084 day-1, 0.074 and 0.098 day-1 for the above mentioned degraders, respectively. The biomass of culture in the presence of geosmin was much higher than that in the absence of geosmin.展开更多
The paper was to find the bacteria to degrade aflatoxin B 1 （AFB 1） and realize the application of biological degradation on AFB 1. Using cumarin as the carbon source and energy on the first screening, then the ten ...The paper was to find the bacteria to degrade aflatoxin B 1 （AFB 1） and realize the application of biological degradation on AFB 1. Using cumarin as the carbon source and energy on the first screening, then the ten strains which were first screened out were taken to degrade AFB 1 100 pg kg^-1. Strain NMO-3 was screened out of ten strains, the degradation ratio of AFB 1 reached 85.7%, which was more prominent than the others （P 〈 0.01）. With the analysis of colony morphology, physiological and biochemistry experiments, and 16S rDNA gene sequence, the strain NMO-3 was finally identified as Stenotrophomonas sp. Using cumarin as the carbon source and energy could screen out the AFB 1 degradation strains. Acute toxicity tests show that the viable number of NMO-3 lower than 3.12 × 10^10 cfu mL-1 is safety. The crude enzyme was obtained by 65% ammonium sulfate fractionation, and it could degrade AFB1. It is the first report for the strain＇s detoxi- AFB1.展开更多
Objectives: To investigate possible sources of Stenotrophomonas maltophilia(S. maltophilia) in the clinical environment.Methods: Different samples were collected from Amol City of Iran. Steps for the identification of...Objectives: To investigate possible sources of Stenotrophomonas maltophilia(S. maltophilia) in the clinical environment.Methods: Different samples were collected from Amol City of Iran. Steps for the identification of S. maltophilia included culturing, biochemical tests, polymerase chain reaction(PCR) of 16 S r RNA gene and 23 S r RNA gene. In addition, production of melanin pigment and patterns of motility of the bacteria, were also investigated.Results: In our study, 20 S. maltophilia strains were isolated from clinical sources,oxygen manometer apparatus of hospitals were 7/110(6.36%), blood was 1/777(0.13%),sputum was 4/40(4%), urine was 1/2 947(0.03%), tap water was 1/240(0.42%) and dental suction was 6/120(5%). The isolated bacteria showed production of melanin pigment with rates of strong, moderate, weak, and lack of pigment. Types of motilities were seen in isolates.Conclusions: The highest percentage of bacteria is isolated of oxygen manometer system and dental suction, yet has not been reported from oxygen manometer system. These bacteria have also been associated with patients who have respiratory problems, so it is essential for staffs of hospitals to draw attention to this source of bacteria.展开更多
In recent years, poly(butylene adipate-co-terephthalate)(PBAT) has been widely used. However, PBAT-degrading bacteria have rarely been reported. PBAT-degrading bacteria were isolated from farmland soil and identified....In recent years, poly(butylene adipate-co-terephthalate)(PBAT) has been widely used. However, PBAT-degrading bacteria have rarely been reported. PBAT-degrading bacteria were isolated from farmland soil and identified. The effects of growth factors on the degradation of PBAT and the lipase activity of PBAT-degrading bacteria were assessed. The degradation mechanism was analyzed using scanning electron microscopy, attenuated total reflection Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, Xray diffraction, and liquid chromatography-mass spectrometry. The results showed that Stenotrophomonas sp. YCJ1 had a significant degrading effect on PBAT. Under certain conditions, the strain could secrete 10.53 U/m L of lipase activity and degrade 10.14 wt.% of PBAT films. The strain secreted lipase to catalyze the degradation of the ester bonds in PBAT, resulting in the production of degradation products such as terephthalic acid, 1,4-butanediol, and adipic acid. Furthermore, the degradation products could participate in the metabolism of YCJ1 as carbon sources to facilitate complete degradation of PBAT, indicating that the strain has potential value for the bioremediation of PBAT in the environment.展开更多
基金supported by the National Science and Technology Major Projects Special for Water Pollution Control and Management (No. 2009ZX07424-003)
文摘Three strains of Gram-negative bacteria capable of removing geosmin from drinking water were isolated from biologically active carbon and identified to be Chryseobacterium sp., Sinorhizobium sp. and Stenotrophomonas sp. based on physio-biochemistry analysis and 16S rRNA gene sequence analysis. Removal efficiencies of 2 mg/L geosmin in mineral salts medium were 84.0%, 80.2% and 74.4% for Chryxeobacterium sp., Sinorhizobium sp. and Stenotrophomonas sp., respectively, while removal efficiencies of 560 ng/L geosmin in filter influent were 84.8%, 82.3% and 82.5%, respectively. The biodegradation of geosmin was determined to be a pseudo first-order reaction, with rate constants at 2 mg/L and 560 ng/L being 0.097 and 0.086 day-1, 0.089 and 0.084 day-1, 0.074 and 0.098 day-1 for the above mentioned degraders, respectively. The biomass of culture in the presence of geosmin was much higher than that in the absence of geosmin.
基金the Ministry of Science and Technology of China (2005DKA21204-11)the Na-tional Natural Science Foundation of China (30571353)the National High Technology Research and Devel-opment Program of China (863 Program,2006AA10Z442)
文摘The paper was to find the bacteria to degrade aflatoxin B 1 （AFB 1） and realize the application of biological degradation on AFB 1. Using cumarin as the carbon source and energy on the first screening, then the ten strains which were first screened out were taken to degrade AFB 1 100 pg kg^-1. Strain NMO-3 was screened out of ten strains, the degradation ratio of AFB 1 reached 85.7%, which was more prominent than the others （P 〈 0.01）. With the analysis of colony morphology, physiological and biochemistry experiments, and 16S rDNA gene sequence, the strain NMO-3 was finally identified as Stenotrophomonas sp. Using cumarin as the carbon source and energy could screen out the AFB 1 degradation strains. Acute toxicity tests show that the viable number of NMO-3 lower than 3.12 × 10^10 cfu mL-1 is safety. The crude enzyme was obtained by 65% ammonium sulfate fractionation, and it could degrade AFB1. It is the first report for the strain＇s detoxi- AFB1.
基金funded by Islamic Azad University Karaj Branch (grant number: 1193)
文摘Objectives: To investigate possible sources of Stenotrophomonas maltophilia(S. maltophilia) in the clinical environment.Methods: Different samples were collected from Amol City of Iran. Steps for the identification of S. maltophilia included culturing, biochemical tests, polymerase chain reaction(PCR) of 16 S r RNA gene and 23 S r RNA gene. In addition, production of melanin pigment and patterns of motility of the bacteria, were also investigated.Results: In our study, 20 S. maltophilia strains were isolated from clinical sources,oxygen manometer apparatus of hospitals were 7/110(6.36%), blood was 1/777(0.13%),sputum was 4/40(4%), urine was 1/2 947(0.03%), tap water was 1/240(0.42%) and dental suction was 6/120(5%). The isolated bacteria showed production of melanin pigment with rates of strong, moderate, weak, and lack of pigment. Types of motilities were seen in isolates.Conclusions: The highest percentage of bacteria is isolated of oxygen manometer system and dental suction, yet has not been reported from oxygen manometer system. These bacteria have also been associated with patients who have respiratory problems, so it is essential for staffs of hospitals to draw attention to this source of bacteria.
基金supported by the Research Fund at the Shaanxi Provincial Science and Technology Department of China (No. 2018SF-375)Beijing Key Laboratory of Plastics Health and Safety Quality Evaluation Technology, Beijing Technology and Business University (No. TQETJP2018 004)。
文摘In recent years, poly(butylene adipate-co-terephthalate)(PBAT) has been widely used. However, PBAT-degrading bacteria have rarely been reported. PBAT-degrading bacteria were isolated from farmland soil and identified. The effects of growth factors on the degradation of PBAT and the lipase activity of PBAT-degrading bacteria were assessed. The degradation mechanism was analyzed using scanning electron microscopy, attenuated total reflection Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, Xray diffraction, and liquid chromatography-mass spectrometry. The results showed that Stenotrophomonas sp. YCJ1 had a significant degrading effect on PBAT. Under certain conditions, the strain could secrete 10.53 U/m L of lipase activity and degrade 10.14 wt.% of PBAT films. The strain secreted lipase to catalyze the degradation of the ester bonds in PBAT, resulting in the production of degradation products such as terephthalic acid, 1,4-butanediol, and adipic acid. Furthermore, the degradation products could participate in the metabolism of YCJ1 as carbon sources to facilitate complete degradation of PBAT, indicating that the strain has potential value for the bioremediation of PBAT in the environment.
