氧化亚铁硫杆菌及其硫氧化机理

烟气SO2引起的酸雨污染是当代世界面临的重大环境问题之一。对烟道气脱硫用微生物—氧化亚铁硫杆菌(Thiobacillus ferrooxidans,T.f)进行了介绍,并在文献分析的基础上,对T.f催化氧化S(IV)机理进行了讨论。     

氧化亚铁硫杆菌固定化技术研究

在生物脱硫过程中 ,以H - 2软性填料作为氧化亚铁硫杆菌 (Thiobacillusferrooxidans)的固定化载体 ,构建了固定床生化反应器。考察了不同稀释率固定下床生化反应器氧化Fe2 + 的情况 ,在通气量为 330L/h ,稀释率为 0 6h-1条件下 ,Fe2 + 最大氧化速率达 7 6 7g[Fe2 + ]/L·h。该反应器连续运行 10 0d,固定化细胞稳定性良好     

氧化亚铁硫杆菌对金属铜的加工

材料加工的传统技术包括物理方法和化学方法。当今 ,生物技术已进入各个领域 ,也渗透到材料加工领域。因此 ,材料加工技术也包括生物方法。根据加工工件体积变化 ,生物方法加工分为生物去除加工 (Ｒｅｍｏｖａｌ)、生物沉积加工 (Ａｄｄｉｔｉｏｎ)和生物成形加工 (Ｄｅｆｏｒｍａｔｉｏｎ)。研究生物加工方法的最早报导是 1 993年日本冈山大学宇野义幸等人[1～ 3] ,证实了细菌对纯铁、纯铜去除加工的可能性以及附加电场的作用。国内的研究工作进一步证实了生物加工能力 ,并加工出微小齿轮[4～5] 。本文报导氧化亚铁硫杆菌 (Ｔｈｉｏｂａｃ…     

紫外线和60Co辐照诱变选育高效嗜酸氧化亚铁硫杆菌

依次利用紫外线和60Co-γ射线辐照诱变的方法对嗜酸氧化亚铁硫杆菌进行诱变,选育高效嗜酸氧化亚铁硫杆菌菌株.结果表明,紫外诱变可以有效提高嗜酸氧化亚铁硫杆菌的Fe2+氧化速率,最佳紫外线诱变时间为240 s.诱变后菌株的Fe2+氧化速率从0.273 g/L/h提高到了0.312 g/L/h.继续利用60Co-γ射线进行...     

氧化亚铁硫杆菌的生物学特性研究进展

对氧化亚铁硫杆菌(Thiobacillus ferrooxidans)的生物学特性进行了评述,对其微生物学特性和能量代谢机理做了较全面的介绍,还指出了现存的问题。     

抗Cu2+嗜酸氧化亚铁硫杆菌的驯化及诱变育种

从我国三大铜矿的酸性矿坑水中富集分离出9个具有较强活性的嗜酸氧化亚铁硫杆菌菌株,经过Cu~(2 )的系列浓度梯度的培养,选出其中天然抗铜能力最强的菌株26~#,在Cu~(2 )浓度为0．20mol/L的9K培养基中能在72h内完全氧化培养基中的Fe~(2 ),在含0．22mol/L Cu2~(2 )的9K培养基中能在192h内完全氧化培养基中的Fe~(2 )。以CuSO_4·5H_2O为单变量驯化介质驯化该26~#抗铜菌株,26~#驯化菌株的Fe~(2 )氧化能力明显增强:在含0．25mol/LCu~(2 )的9K培养基中能在84h内完全氧化其中的Fe~(2 )。为了提高驯化菌的稳定性,将驯化后的26~#菌株用紫外线进行诱变。研究结果表明:驯化诱变对菌种的改良有重要的作用,诱变后菌株的生长性能稳定,氧化活性进一步提高,26~#驯化诱变菌在0．25mol/LCu~(2 )存在的条件下完全氧化9K培养基中Fe~(2 )的时间约为60h,对Fe~(2 )氧化能力明显强于驯化菌及野生菌。     

氧化亚铁硫杆菌培养过程中沉淀的研究

为了减少氧化亚铁硫杆菌培养过程中产生的沉淀,对氧化亚铁硫杆菌培养过程中产生的沉淀物进行了研究,确定了在pH为1．5,K2HPO4用量为0．25g/l,KH2PO4为0．195g/l时菌体可以保持其最高氧化活性,同时产生最少量沉淀物的培养条件,并发现沉淀物对菌体的生长和氧化Fe^2 没有影响。利用饥饿状态的氧化亚铁硫杆菌证明了菌体在一定条件下可以利用黄铁钒沉淀中的部分离子进行生长繁殖。     

氧化亚铁硫杆菌分离复壮及固定化的研究

用稀释涂布平板法从已退化的氧化亚铁硫杆菌（Thiobacillus ferrooxidans）菌液中分离出氧化活性较高、生命力强的氧化亚铁硫杆菌T1。以H2软性填料作为氧化亚铁硫杆菌的固定化载体,构建了固定床生物反应器。考察了固定床生物反应器氧化Fe2+的情况：Fe2+最大氧化速率达7.67g/(L·h)。并对固定床生物反应器运行过程中在载体表面形成的沉淀物进行了研究,通过X衍射证明此沉淀物为黄钾铁矾［Kfe3(SO4)2(OH)6］。     

氧化亚铁硫杆菌生物冶金的新进展

综述了Thiobacillus ferrooxidans生物冶金的催化作用机制,能量变化,细胞外多聚物和基底金属在浸出过程中的作用和影响,以及温度,矿物的大小,空气分离器,pH,细菌载体的影响。     

氧化亚铁硫杆菌氧化亚硫酸盐的动力学研究

实验用Ms培养基,利用去除铁离子的氧化亚铁硫杆菌(Thiobacillus ferrooxidans)进行了细菌亚硫酸盐的生长代谢研究。实验结果表明氧化亚铁硫杆菌对亚硫酸根具有一定的氧化能力。用Origin 7.0对实验数据进行拟合处理,表明了氧化亚铁硫杆菌催化氧化亚硫酸盐的动力学方程符合Hill方程。氧化亚铁硫杆菌催化氧化亚硫酸盐是一个底物抑制的细胞反应,其KS值随pH值和底物浓度的改变而变化。pH值对反应有很大的影响,pH值越接近中性KS就越小,反应速率就越大。     

Mechanism of microbial flotation using Thiobacillus ferrooxidans for pyrite suppression

Microbial desulfurization might be developed as a new process for the removal of pyrite sulfur from coal sluries such as coal-water mixture (CWM). An application of iron-oxidizing bacterium Thiobacillus ferrooxidans to flotation would shorten the periods of the microbial removal of pyrite from some weeks by leaching methods to a few minutes. The floatability of pyrite in flotation was mainly reduced by T. ferrooxidans itself rather than by other microbial substances in bacterial culture as additive of flotation liquor. Floatability was suppressed within a few seconds by bacterial contact. The suppression was proportional to increasing the number of cells observed between bacterial adhesion and the suppression of floatability. If 25% of the total pyrite surface area covered with the bacteria, pyrite floatability would be completely depressed. Bacteria that lost their iron-oxidizing activities by sodium cyanide treatment were also able to adhere to pyrite and reduced pyrite floatability as much as normal bacteria did. Thiobacillus ferrooxidans ATCC 23270, T-1, 9, and 11, which had different iron-oxidizing abilities, suppressed floatability to similar-levels. The oxidizing ability of bacteria did not influence the suppressing effect. These results showed the mechanism of the suppression of pyrite floatability by bacteria. Quick bacterial adhesion to pyrite induced floatability suppression by changing the surface property from hydrophobic. The quick adhesion of the bacterium was the novel function which worked to change the surface property of pyrite to remove it from coal. (c) 1993 John Wiley & Sons, Inc.     

Mechanism of Pyrite Dissolution in the Presence of Thiobacillus ferrooxidans

In spite of the environmental and commercial interests in the bacterial leaching of pyrite, two central questions have not been answered after more than 35 years of research: does Thiobacillus ferrooxidans enhance the rate of leaching above that achieved by ferric sulfate solutions under the same conditions, and if so, how do the bacteria affect such an enhancement? Experimental conditions of previous studies were such that the concentrations of ferric and ferrous ions changed substantially throughout the course of the experiments. This has made it difficult to interpret the data obtained from these previous works. The aim of this work was to answer these two questions by employing an experimental apparatus designed to maintain the concentrations in solution at a constant value. This was achieved by using the constant redox potential apparatus described previously (P. I. Harvey, and F. K. Crundwell, Appl. Environ. Microbiol. 63:2586–2592, 1997; T. A. Fowler, and F. K. Crundwell, Appl. Environ. Microbiol. 64:3570–3575, 1998). Experiments were conducted in both the presence and absence of T. ferrooxidans, maintaining the same conditions in solution. The rate of dissolution of pyrite with bacteria was higher than that without bacteria at the same concentrations of ferrous and ferric ions in solution. Analysis of the dependence of the rate of leaching on the concentration of ferric ions and on the pH, together with results obtained from electrochemical measurements, provided clear evidence that the higher rate of leaching with bacteria is due to the bacteria increasing the pH at the surface of the pyrite.     

Mechanism of pyrite dissolution in the presence of Thiobacillus ferrooxidans.

In spite of the environmental and commercial interests in the bacterial leaching of pyrite, two central questions have not been answered after more than 35 years of research: does Thiobacillus ferrooxidans enhance the rate of leaching above that achieved by ferric sulfate solutions under the same conditions, and if so, how do the bacteria affect such an enhancement? Experimental conditions of previous studies were such that the concentrations of ferric and ferrous ions changed substantially throughout the course of the experiments. This has made it difficult to interpret the data obtained from these previous works. The aim of this work was to answer these two questions by employing an experimental apparatus designed to maintain the concentrations in solution at a constant value. This was achieved by using the constant redox potential apparatus described previously (P. I. Harvey, and F. K. Crundwell, Appl. Environ. Microbiol. 63:2586-2592, 1997; T. A. Fowler, and F. K. Crundwell, Appl. Environ. Microbiol. 64:3570-3575, 1998). Experiments were conducted in both the presence and absence of T. ferrooxidans, maintaining the same conditions in solution. The rate of dissolution of pyrite with bacteria was higher than that without bacteria at the same concentrations of ferrous and ferric ions in solution. Analysis of the dependence of the rate of leaching on the concentration of ferric ions and on the pH, together with results obtained from electrochemical measurements, provided clear evidence that the higher rate of leaching with bacteria is due to the bacteria increasing the pH at the surface of the pyrite.     

Mechanism of oxidation of inorganic sulfur compounds by thiosulfate-grown Thiobacillus thiooxidans

Thiobacillus thiooxidans was grown at pH 5 on thiosulfate as an energy source, and the mechanism of oxidation of inorganic sulfur compounds was studied by the effect of inhibitors, stoichiometries of oxygen consumption and sulfur, sulfite, or tetrathionate accumulation, and cytochrome reduction by substrates. Both intact cells and cell-free extracts were used in the study. The results are consistent with the pathway with sulfur and sulfite as the key intermediates. Thiosulfate was oxidized after cleavage to sulfur and sulfite as intermediates at pH 5, the optimal growth pH on thiosulfate, but after initial condensation to tetrathionate at pH 2.3 where the organism failed to grow. N-Ethylmaleimide (NEM) inhibited sulfur oxidation directly and the oxidation of thiosulfate or tetrathionate indirectly. It did not inhibit the sulfite oxidation by cells, but inhibited any reduction of cell cytochromes by sulfur, thiosulfate, tetrathionate, and sulfite. NEM probably binds sulfhydryl groups, which are possibly essential in supplying electrons to initiate sulfur oxidation. 2-Heptyl-4-hydroxy-quinoline N-oxide (HQNO) inhibited the oxidation of sulfite directly and that of sulfur, thiosulfate, and tetrathionate indirectly. Uncouplers, carbonyl cyanide-m-chlorophenylhydrazone (CCCP) and 2,4-dinitrophenol (DNP), inhibited sulfite oxidation by cells, but not the oxidation by extracts, while HQNO inhibited both. It is proposed that HQNO inhibits the oxidation of sulfite at the cytochrome b site both in cells and extracts, but uncouplers inhibit the oxidation in cells only by collapsing the energized state of cells, delta muH+, required either for electron transfer from cytochrome c to b or for sulfite binding.     

He—Ne激光对家蚕诱变效应的研究

采用一定剂量的ＨｅＮｅ激光辐照家蚕蛹,在子代与对照相比较,出现熟性、茧形、斑纹等多种变异,利用ＰＡＧＥ,进行血液蛋白质电泳分析结果,也产生谱带数目及活性的变化,首次证明ＨｅＮｅ激光对家蚕具有一定的诱变效应。     

Mechanism of Action of Nalidixic Acid on Escherichia coli V. Possible Mutagenic Effect

Cook, Thomas M., (Sterling-Winthrop Research Institute, Rensselaer, N.Y.), William A. Goss, and William H. Deitz. Mechanism of action of nalidixic acid on Escherichia coli. V. Possible mutagenic effect. J. Bacteriol. 91:780-783. 1966.-With a streptomycin-dependent organism, Escherichia coli ATCC 11143, it has been shown that exposure to nalidixic acid, under conditions permitting some bactericidal action, results in an increased number of streptomycin-independent bacteria among the survivors. This effect is evident only with proliferating cultures, and is related to the concentration of nalidixic acid and the duration of exposure.     

Transpositional Mutagenesis of Thiobacillus novellus and Thiobacillus versutus

Transpositional mutagenesis of Thiobacillus novellus by Tn501 was achieved by means of the incompatibility of IncP plasmids. Tn501 insertion caused three types of mutant phenotypes: isoleucine auxotrophy, lysine auxotrophy, and a reduced ability to oxidize reduced sulfur compounds and to fix CO₂. Oxidation rates for elemental sulfur (S⁰), thiosulfate (S₂O₃²⁻), and tetrathionate (S₄O₆²⁻) in mutants of the latter type were reduced relative to those of the nonmutant control strain. Incorporation of labeled bicarbonate (H¹⁴CO₃⁻) was also significantly impaired. Although suicide vehicles were not useful for the introduction of transposons into T. novellus, this method was effective for the Tn1721-induced mutagenesis of Thiobacillus versutus. Tn1721 insertions resulted in the loss of the natural resistance of T. versutus to arsenate and gentamicin and in auxotrophies for isoleucine-valine, arginine, phenylalanine, valine, and panthothenate. Transpositional mutagenesis by either method should prove to be a useful tool for further study of these and other members of the genus Thiobacillus.