The bioleaching of pyrite and biosolubilization of rock phosphate （RP） in 9K basal salts medium were compared by the following strains of an autotrophic acidophilic bacterium, Acidithiobacillus ferrooxidans, a heter...The bioleaching of pyrite and biosolubilization of rock phosphate （RP） in 9K basal salts medium were compared by the following strains of an autotrophic acidophilic bacterium, Acidithiobacillus ferrooxidans, a heterotrophic acidophilic bacterium, Acidiphilium cryptum, and mixed culture of At. ferrooxidans and A. cryptum. The results show that A. cryptum is effective in enhancing the bioleaching of pyrite and biosolubilization of RP in the presence of At. ferrooxidans, although it could not oxidize pyrite and solubilize RP by itself. This effect is demonstrated experimentally that A. cryptum enhances a decrease in pH and an increase in redox potential, concentration of total soluble iron and planktonic part bacterial number in the broth during pyrite bioleaching processes by At. ferrooxidans. The mixed culture of At. ferrooxidans and A. cryptum leads to the most extensive soluble phosphate released at 30 °C. Pulp density exceeding 3% is shown to adversely influence the release of soluble phosphate by the consortium of At. ferrooxidans and A. cryptum. It is essential to add pyrite to the 9K basal salts medium for the biosolubilization of RP by the mixed culture of At. ferrooxidans and A. cryptum, and the percentage of soluble phosphate released is the greatest when the mass ratio of RP to pyrite is 1：2 or 1：3.展开更多
The original strains Acidithiobacillusferrooxidans GF and Acidiphilium cryptum DXI-1 were isolated from the drainage of some caves riched in chalcopyrite in Dexing Mine in Jiangxi Province of China. The optimum temper...The original strains Acidithiobacillusferrooxidans GF and Acidiphilium cryptum DXI-1 were isolated from the drainage of some caves riched in chalcopyrite in Dexing Mine in Jiangxi Province of China. The optimum temperature and pH for growth were 30 ℃ and 3.5 for Ac. cryptum DXI-1, and 30 ℃ and 2.0 for At. ferrooxidans GF, respectively. For Ac. cryptum DXI-1, the optimum UV radiating time was 60 s and the positive mutation rate was 22.5%. The growth curves show that Ac. cryptum after mutagenesis reached stationary phase within 60 h, which was 20 h earlier than the original strain. For At. ferrooxidans GF, the optimum mutation time was 60 s and the positive mutation rate was 35%. The most active UV-mutated strain At. ferrooxidans GF oxidized all the ferrous after 48 h. The bioleaching experiments showed that bioleaching with the mixture of UV-mutated strains of At. ferrooxidans GF and A c. cryptum DX1-1 （1：1） could extract 3.01 g/L of copper after 30 d, while the extracted copper was 2.63 g/L with the mixture of the original strains before UV-mutation. At the end of the bioleaching experiments, the proportion of the cell density in the cultures ofAc. cryptum DXI-1 andAt.ferrooxidans GF was approximately 1：5.展开更多
A new bacterial strain,was designated as strain Acidiphilium cryptum DX1-1,accumulates intracellular poly-β-hydroxybutyrate particles,four methods which have advantages and disadvantages for each were employed to ext...A new bacterial strain,was designated as strain Acidiphilium cryptum DX1-1,accumulates intracellular poly-β-hydroxybutyrate particles,four methods which have advantages and disadvantages for each were employed to extract PHB.Chloroform-sodium hypochlorite method is the best in extracting PHB form Acidiphilium cryptum DX1-1.The extraction rate reaches 73%,the purification rate is 92% and molecular weight is 326 kg/mol.Then the PHB extracted by this method was analyzed by ultraviolet-visible absorption spectroscopy,fourier transform infrared（FT-IR） and nuclear magnetic resonance（NMR）.The results show that PHB from strain DX1-1 has the same biochemical structure and character with PHB standard.Mass spectrometer（MS） analysis reveals that the long chain of PHB is destroyed when treated by chloroform-sodium hypochlorite.The differential scanning calorimetry（DSC） of PHB shows PHB from Acidiphilium cryptum DX1-1 has low degree of crystallinity which makes the PHB has a wider range of applications.展开更多
为了探索隐藏嗜酸菌(Acidiphilium cryptum)对多变极端矿山环境条件的感知和反应分子机制,预测和分析了隐藏嗜酸菌JF-5菌株的双组分信号转导系统(Two-component signal transduction system,TCS)的分布、结构及功能.鉴定了9对成对TCSs、...为了探索隐藏嗜酸菌(Acidiphilium cryptum)对多变极端矿山环境条件的感知和反应分子机制,预测和分析了隐藏嗜酸菌JF-5菌株的双组分信号转导系统(Two-component signal transduction system,TCS)的分布、结构及功能.鉴定了9对成对TCSs、2个杂合结构TCSs、3个孤儿组氨酸蛋白激酶(HK)和5个孤儿反应调节蛋白(RR);发现5个TCSs参与隐藏嗜酸菌对重金属响应转录调控;大多数HKs的N-末端具有接受信号的跨膜区、HAMP或PAS等结构域,RRs主要是OmpR亚家族,占总RRs的40%以上;从进化关系上来看,一些处在进化树同一分支上的共同聚簇TCS基因可能具有相同的进化途径.本研究结果可为研究隐藏嗜酸菌在极端环境中适应性分子机制提供新的方向.展开更多
基金Project(51004078)supported by the National Natural Science Foundation of ChinaProject(NCET-11-0965)supported by the Program for New Century Excellent Talents in University,China+2 种基金Project(2012FFA101)supported by the Natural Science Foundation of Hubei Province,ChinaProject(IRT0974)supported by the Program for Changjiang Scholars and Innovative Research Team in University,ChinaProject(2011CB411901)supported by the National Basic Research Program of China
文摘The bioleaching of pyrite and biosolubilization of rock phosphate （RP） in 9K basal salts medium were compared by the following strains of an autotrophic acidophilic bacterium, Acidithiobacillus ferrooxidans, a heterotrophic acidophilic bacterium, Acidiphilium cryptum, and mixed culture of At. ferrooxidans and A. cryptum. The results show that A. cryptum is effective in enhancing the bioleaching of pyrite and biosolubilization of RP in the presence of At. ferrooxidans, although it could not oxidize pyrite and solubilize RP by itself. This effect is demonstrated experimentally that A. cryptum enhances a decrease in pH and an increase in redox potential, concentration of total soluble iron and planktonic part bacterial number in the broth during pyrite bioleaching processes by At. ferrooxidans. The mixed culture of At. ferrooxidans and A. cryptum leads to the most extensive soluble phosphate released at 30 °C. Pulp density exceeding 3% is shown to adversely influence the release of soluble phosphate by the consortium of At. ferrooxidans and A. cryptum. It is essential to add pyrite to the 9K basal salts medium for the biosolubilization of RP by the mixed culture of At. ferrooxidans and A. cryptum, and the percentage of soluble phosphate released is the greatest when the mass ratio of RP to pyrite is 1：2 or 1：3.
基金Project(2010CB630902)supported by the National Basic Research Program of ChinaProjects(50674101,50974140)supported by the National Natural Science Foundation of China
文摘The original strains Acidithiobacillusferrooxidans GF and Acidiphilium cryptum DXI-1 were isolated from the drainage of some caves riched in chalcopyrite in Dexing Mine in Jiangxi Province of China. The optimum temperature and pH for growth were 30 ℃ and 3.5 for Ac. cryptum DXI-1, and 30 ℃ and 2.0 for At. ferrooxidans GF, respectively. For Ac. cryptum DXI-1, the optimum UV radiating time was 60 s and the positive mutation rate was 22.5%. The growth curves show that Ac. cryptum after mutagenesis reached stationary phase within 60 h, which was 20 h earlier than the original strain. For At. ferrooxidans GF, the optimum mutation time was 60 s and the positive mutation rate was 35%. The most active UV-mutated strain At. ferrooxidans GF oxidized all the ferrous after 48 h. The bioleaching experiments showed that bioleaching with the mixture of UV-mutated strains of At. ferrooxidans GF and A c. cryptum DX1-1 （1：1） could extract 3.01 g/L of copper after 30 d, while the extracted copper was 2.63 g/L with the mixture of the original strains before UV-mutation. At the end of the bioleaching experiments, the proportion of the cell density in the cultures ofAc. cryptum DXI-1 andAt.ferrooxidans GF was approximately 1：5.
基金Funded by the National Natural Science Foundation for Distinguished Group (No. 50621063)the National Natural Science Foundation of China (No.50674101)the National Innovation Experiment Program for University Students (No. 81053321)
文摘A new bacterial strain,was designated as strain Acidiphilium cryptum DX1-1,accumulates intracellular poly-β-hydroxybutyrate particles,four methods which have advantages and disadvantages for each were employed to extract PHB.Chloroform-sodium hypochlorite method is the best in extracting PHB form Acidiphilium cryptum DX1-1.The extraction rate reaches 73%,the purification rate is 92% and molecular weight is 326 kg/mol.Then the PHB extracted by this method was analyzed by ultraviolet-visible absorption spectroscopy,fourier transform infrared（FT-IR） and nuclear magnetic resonance（NMR）.The results show that PHB from strain DX1-1 has the same biochemical structure and character with PHB standard.Mass spectrometer（MS） analysis reveals that the long chain of PHB is destroyed when treated by chloroform-sodium hypochlorite.The differential scanning calorimetry（DSC） of PHB shows PHB from Acidiphilium cryptum DX1-1 has low degree of crystallinity which makes the PHB has a wider range of applications.
文摘为了探索隐藏嗜酸菌(Acidiphilium cryptum)对多变极端矿山环境条件的感知和反应分子机制,预测和分析了隐藏嗜酸菌JF-5菌株的双组分信号转导系统(Two-component signal transduction system,TCS)的分布、结构及功能.鉴定了9对成对TCSs、2个杂合结构TCSs、3个孤儿组氨酸蛋白激酶(HK)和5个孤儿反应调节蛋白(RR);发现5个TCSs参与隐藏嗜酸菌对重金属响应转录调控;大多数HKs的N-末端具有接受信号的跨膜区、HAMP或PAS等结构域,RRs主要是OmpR亚家族,占总RRs的40%以上;从进化关系上来看,一些处在进化树同一分支上的共同聚簇TCS基因可能具有相同的进化途径.本研究结果可为研究隐藏嗜酸菌在极端环境中适应性分子机制提供新的方向.
