Bioleaching of anilite by Acidithiobacillus ferrooxidans

In order to characterize the efficiency of copper bioleaching from anilite using pure cultures of Acidithiobacillus ferrooxidans in the absence and presence of ferrous sulphate,the experiments were carried out in shake flasks with or without 4 g/L ferrous sulphate(FeSO_4·7H_2O)at pH 2.0,150 r/min and 35℃.The tests show that Acidithiobacillus ferrooxidans is unable to attack anilite in iron-free 9K medium.Anilite is rapidly oxidized by bacterial leaching when ferrous sulphate is added.Chemical oxidation o...     

Isolation and characterization of acidophilic bacterium from Gaofeng Mine in China

An acidophilic, chemolithotrophic and ferrous oxidizing bacterium strain GF was isolated from the acid mine drainage （AMD） of Gaofeng Mine, Guangxi Province, China using 9K enrichment medium, and then purified on solid ferrous-agarose medium. The physiological experiments show that it can use ferrous or sulfur as sole energy and a low level （0.1%, w/v） of peptone can accelerate the growth of the isolated strain. The optimum pH and temperature for growth are 2.0 and 30 ℃, respectively. The isolated strain shares 99.64% identities of 16S rRNA gene with the type strain Acidthiobacillusferrooxidans ATCC 23270 and 100% identities of iro gene （CDS） with A.ferrooxidans strain Fe-1. These results show that the strain can be considered as A cidthiobacillus ferrooxidans. Because of the high activity of oxidizing ferrous and sulfide mineral, strain GF was used in bioleaching of marmatite. The Zn concentration is 0.273 g/L under the steriled control and 7.30 g/L with adapted GF strain incubated after 29 d in leaching marmatite. The isolated strain GF can be used to leach marmatite in industry application.     

Liquid-nitrogen cryopreservation of three kinds of autotrophicbioleaching bacteria

Three kinds of autotrophic bioleaching bacteria strains, including mesophilic and acidophilic ferrous ion-oxidizing bacteria Acidithiobacillus ferrooxidans （A. ferrooxidans）, mesophilic and acidophilic sulfur-oxidizing bacteria Acidithiobacillus thiooxidans （A. thiooxidans）, and moderately thermophilic sulfur-oxidizing bacteria Acidianus brierleyi, were cryopreserved in liquid nitrogen and their ferrous ion- or sulfur-oxidizing activities were investigated and compared with the original ones. The results revealed that ferrous ion/sulfur oxidation activities of the strains were almost equal before and after cryopreservation. Glycerin was used as cryoprotective agent. In conclusion, liquid-nitrogen cryopreservation is a simple and effective method for autotrophic bioleaching microorganisms.     

Bioleaching of chalcopyrite by pure and mixed culture

The bioleaching of chalcopyrite in shake flasks was investigated by using pure Acidithiobacillusferrooxidans and mixed culture isolated from the acid mine drainage in Yushui and Dabaoshan Copper Mine in China, marked as YS and DB, respectively. The mixed culture consisted mainly of Acidithiobacillus fOrrooxidans, Acidithiobacillus thiooxidans, and Leptospirillum spp. （Leptospirillum ferriphilum and Leptospirillum ferrooxians）. The results show that the mixed culture is more efficient than the pure Acidithiobacillus ferrooxidans because of the presence of the sulfur-oxidizing cultures that positively increase the dissolution rate and the recovery of copper from chalcopyrite. The pH value decreases with the decrease of chalcopyrite leaching rate, because of the formation ofjarosite as a passivation layer on the mineral surface during bioleaching. In the bioleaching using the mixed culture, low pH is got from the sulfur oxidizing inhibiting, the formation ofjarosite. The copper extraction reaches 46.27% in mixed culture and 30.37% in pure Acidithiobacillusferrooxidans after leaching for 75 d.     

镍黄铁矿电化学生物氧化过程的分解机理(英文)

应用表面粘附和没有粘附Acidithiobacillus ferrooxidans的镍黄铁矿粉末微电极进行电化学测试,以说明镍黄铁矿氧化分解的机理。循环伏安CV结果显示,在-0.2V的低电位区域,在镍、铁离子析出时镍黄铁矿转变为中间相Fe4.5-yNi4.5-xS8-z;当电位在-0.2V到0.2V区间时,有不稳定的紫硫镍矿Fe3Ni3S4和FeNi2S4形成并在表面伴有元素硫的产生;当电位增加到0.2V以上时,不稳定相将全部分解;在高电位0.7V时,析出的亚铁离子被氧化为高铁离子。嗜酸氧化亚铁硫杆菌Acidithiobacillus ferrooxidans的存在使峰电位增高,反应起始电位负移,并对表面形成的元素硫有氧化去除作用。这一过程可通过-0.75到-0.5V电位区间发生的的还原反应证实。生物浸出和电化学实验结果均表明当pH2时溶液酸度的增加对氧化过程有轻度的阻碍作用。     

Bioleaching of anilite by Acidithiobacillus ferrooxidans

In order to characterize the efficiency of copper bioleaching from anilite using pure cultures of Acidithiobacillus ferrooxidans in the absence and presence of ferrous sulphate, the experiments were carried out in shake flasks with or without 4 g/L ferrous sulphate (FeSO₄·7H₂O) at pH 2.0, 150 r/min and 35°C. The tests show that Acidithiobacillus ferrooxidans is unable to attack anilite in iron-free 9K medium. Anilite is rapidly oxidized by bacterial leaching when ferrous sulphate is added. Chemical oxidation of anilite is slow compared with Acidithiobacillus ferrooxidans initiated solubilization in the presence of iron. The EDAX analysis of the surfaces of anilite confirms that sulfur coating layer is present as a reaction product on the surface of the bacterially leached mineral.     

Bioleaching of chalcopyrite by UV-induced mutagenized Acidiphilium cryptum and Acidithiobacillus ferrooxidans

The original strains Acidithiobacillus ferrooxidans GF and Acidiphilium cryptum DX1-1 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 DX1-1,and 30℃and 2.0 for At.ferrooxidans GF,respectively.For Ac.cryptum DX1-1,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 ...     

Mechanism of silver-influenced bacterial leaching of chalcopyrite, pyrite and a copper ore

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嗜酸氧化亚铁硫杆菌亚铁氧化系统研究进展

嗜酸氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)是目前研究得最多的浸矿细菌,其能量代谢途径复杂多样。在有氧条件下,A.ferrooxidans以氧化Fe2 、H2或(和)各种还原性硫化物提供能量来生长,在亚铁氧化系统中,A.ferrooxidans的各种菌株氧化亚铁后产生的电子经大致相同的传递途径传递给最终电子受体O2,但是最初电子受体可能有所不同。讨论了A.ferrooxidans亚铁氧化系统中电子顺电势梯度传递的各个电子传递载体的组成,基因结构和特征以及可能的相互作用机制;同时,介绍了A.ferrooxidans生长过程中,少量电子经细胞色素bc1复合体逆电势梯度传递、参与还原力NAD(P)H的生成和CO2固定过程中可能存在的电子传递模式,以及A.ferrooxidans在不同生长基质中生长时rus操纵子的转录调控模式。     

元素硫对黄铜矿生物浸出行为及群落结构的影响(英文)

研究3种典型铁/硫代谢菌—Acidithiobacillus ferrooxidans,Leptospirillum ferriphilum及Acidithiobacillus thiooxidans混合浸出黄铜矿过程中铁/硫氧化活性、群落结构(PCR-RFLP)的变化,以及不同浓度的元素硫对其影响。结果发现,加入3.193g/L元素硫能促进细菌的表观硫氧化活性,改变浸矿体系的群落结构,并进一步影响钝化层的形成、金属离子的溶出,其浸出率(71%)较未添加硫的(67%)有一定程度的提高。而过量的元素硫会抑制铜的浸出(浸出率44%)。     

Bacterial leaching of chalcopyrite and bornite with native bioleaching microorganism

A native mesophilic iron-oxidizing bacterium, Acidithiobacillus ferrooxidans, has been isolated （30 ℃） from a typical, lead-zinc concentrate of Dachang Mine in the region of Liuzhou located in the southwest of China. Two typical copper sulfide minerals, chalcopyrite and bornite, were from Meizhou Copper Mine in the region of Guangdong Province, China. Variation of pH and cell growth on time and effects of some factors such as temperature, inoculation cell number, and pulp density on the bioleaching of chalcopyrite and bornite were investigated. The results obtained from the bioleaching experiments indicate that the efficiency of copper extraction depends on all of the mentioned variables, especially the pulp density has more effect than the other factors on the microorganism. In addition, the results show that the maximum copper recovery was achieved using a mesophilic culture. The copper dissolution reached 51.34% for the chalcopyrite while it was 72.35% for the bornite at pH 2.0, initial Fe（ Ⅱ ） concentration 9 g/L and pulp density 5%, after 30 d.     

Catalytic effect of activated carbon on bioleaching of low-grade primary copper sulfide ores

The catalytic effect of activated carbon on the bioleaching of low-grade primary copper sulfide ores using mixture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans was investigated. The results show that the addition of activated carbon can greatly accelerate the rate and efficiency of copper dissolution from low-grade primary copper sulfide ores. The solution with the concentration of 3.0 g/L activated carbon is most beneficial to the dissolution of copper. The resting time of the mixture of activated carbon and ores has an impact on the bioleaching of low-grade primary copper sulfide ores. The 2 d resting time is most favorable to the dissolution of copper. The enhanced dissolution rate and efficiency of copper can be attributed to the galvanic interaction between activated carbon and chalcopyrite. The addition of activated carbon obviously depresses the dissolution of iron and the bacterial oxidation of ferrous ions in solution. The lower redox potentials are more favorable to the copper dissolution than the higher potentials for low-grade primary copper sulfide ores in the presence of activated carbon.     

Screening and characterization of Acidiphilium sp. PJH and its role in bioleaching

A Gram-negative,facultative autotrophic bacterium strain PJH was isolated from the acidic mine drainages sampled in Dexing Mine,Jiangxi Province,China.The isolate grew in a pH range of 1.0-6.0,with pH and temperature optima of 3.5 and 40 ℃,respectively.Spectroscopic experiments show that strain PJH can synthesize polyhydroxybutyrate (PHB).A phylogenetic analysis based on 16S rRNA sequences shows that the isolate belongs to the genus Acidiphilium.Strain PJH has the capability of leaching chalcopyrite.Bioleaching experiments show that it can improve the leaching rate of chalcopyrite by 10.3% when mixed with L.ferriphilium YTW315 after 35 d.Strain PJH has the potential in application to bioleach chalcopyrite with other mesophilic leaching microbes.     

表面活性剂Tween-80对Acidithiobacillus ferrooxidans硫氧化和硫代谢相关蛋白质基因表达的影响(英文)

研究了表面活性剂 Tween-80 对 Acidithiobacillus ferrooxidans ATCC 23270 生长、硫氧化和硫代谢相关典型基因表达的影响。结果表明,当培养基中含有 10 2g/L Tween-80 时,A. ferrooxidans 的生长以及其对不溶性底物(S0和 CuFeS2)的代谢得到了促进。在该条件下,经过 24 d 的生物浸出,黄铜矿的铜离子浸出率比对照组(不含 Tween-80)高 16%。FT-IR 光谱分析表明,这可能是由于 Tween-80 的存在而导致胞外多聚物成分发生变化而引起的。用 RT-qPCR 来分析 17 个硫代谢相关基因在 Tween-80 存在时的表达差异。胞外蛋白质基因表达下调表明了Tween-80 对细菌硫吸附作用的影响。硫代谢相关酶基因表达水平的变化为硫代谢的研究提供了参考。     

镁离子浓度对氧化亚铁硫杆菌生长动力学的影响

在氧化亚铁硫杆菌(T.f)培养过程中其他营养物质足量的情况下,通过考察不同初始Mg2+浓度对氧化亚铁硫杆菌(T.f)生长活性的影响,得到在不同Mg2+浓度下细菌的生长曲线。结果表明:T.f对Mg2+具有一定的耐受能力;当培养基中ρ(Mg2+)≤10 g/L时,Mg2+对细菌生长活性影响很小;其ρ(Mg2+)为15 g/L时,Mg2+开始产生延迟效应,抑制细菌生长;ρ(Mg2+)为20 g/L时,细菌生长完全受到抑制。同时利用基于存在非竞争性抑制的Monod方程,建立了T.f在高Mg2+浓度下的生长动力学方程模型,确定在不同条件下细菌生长动力学参数,包括最大比生长速率μmax、Monod常数Km及镁离子抑制常数KI。利用correl系数工具分析细菌比生长速率的实验值和模拟值之间的相关系数为0.973,表明该动力学方程能较好地描述Mg2+浓度对氧化亚铁硫杆菌生长的影响。     

一种用于嗜酸性氧化亚铁硫杆菌液氮保藏的新型保护剂的保藏效果(英文)

对一种用于嗜酸性氧化亚铁硫杆菌液氮冷藏新型保护剂GP的保藏效果进行研究。依据最大细胞复苏率及最高亚铁氧化活性确定该新型保护剂的最佳使用浓度。结果表明,保护剂的最佳浓度为30%,在此浓度下细胞复苏率达到84.4%,且能在120h内完全氧化培养基中的亚铁,培养6d后菌体浓度达到5.8×107cell/mL。此外,解冻细胞在9K培养基中培养6d后,对活细胞复苏的最佳GP残留浓度为0.6%(体积分数)。在此浓度下,菌株DC完全氧化亚铁需要108h,并且最终菌体浓度为6.8×107cell/mL.因此,GP是一种简单、有效的嗜酸性氧化亚铁硫杆菌液氮保藏的冷冻保护剂。     

Bio-leaching of low-grade large porphyry chalcopyrite-containing ore

1　ＩＮＴＲＯＤＵＣＴＩＯＮＤｅｘｉｎｇＣｏｐｐｅｒＭｉｎｅｉｎＪｉａｎｇｘｉＰｒｏｖｉｎｃｅ ,Ｃｈｉ ｎａ ,ｉｓａｌａｒｇｅｃｏｐｐｅｒｄｅｐｏｓｉｔａｔｗｈｉｃｈａｒｏｕｎｄ 50 0ｍｉｌ ｌｉｏｎｔｏｎｓｏｆｗａｓｔｅｒｏｃｋｓｃｏｎｔａｉｎｉｎｇ 0 .1%～ 0 .3%ｃｏｐｐｅｒａｒｅｐｒｏｄｕｃｅｄ ,ａｎｄａｐｐｒｏｘｉｍａｔｅｌｙ 1.2ｍｉｌｌｉｏｎｔｏｎｓｏｆｍｅｔａｌｃｏｐｐｅｒｃｏｎｔａｉｎｅｄｉｎｔｈｅｓｅｌｏｗ ｇｒａｄｅｏｒｅｓｃｏｕｌｄｎｏｔｂｅｅｃｏｎｏｍｉｃａｌｌｙｒｅｃｏｖｅｒｅ…     

Screening and characterization of Acidiphilium sp. PJH and its role in bioleaching

A Gram-negative, facultative autotrophic bacterium strain PJH was isolated from the acidic mine drainages sampled in Dexing Mine, Jiangxi Province, China. The isolate grew in a pH range of 1.0 6.0, with pH and temperature optima of 3.5 and 40 ℃, respectively. Spectroscopic experiments show that strain PJH can synthesize polyhydroxybutyrate （PHB）. A phylogenetic analysis based on 16S rRNA sequences shows that the isolate belongs to the genus Acidiphilium. Strain PJH has the capability of leaching chalcopyrite. Bioleaching experiments show that it can improve the leaching rate of chalcopyrite by 10.3% when mixed with L. ferriphilium YTW315 after 35 d. Strain PJH has the potential in application to bioleach chalcopyrite with other mesophilic leaching microbes.     

A new strain Leptospirillum ferriphilum YTW315 for bioleaching of metal sulfides ores

A new strain named YTW315 was isolated from Dexing area using the double-layer culture technique. The morphological, biochemical and physiological characteristics of YTW315 were studied. Physiological investigation indicates that the strain YTW315 is a strict (obligate) chemolithoautotroph, metabolizing ferrous iron and pyrite. The optimal growth conditions for the strain are 40 ℃ and pH 1.6. A phylogenetic analysis based on 16S rRNA sequences shows that the isolate is clustered to Leptospirillum ferriphilum with 99.8% similarity to Leptospirillum ferriphilum strain Fairview and ATCC 49881. The molar fraction of DNA (G+C) of the isolate is 58.1%. The strain can tolerate high concentration of Fe(Ⅲ) and As(V) (500 mmol/L and 50 mmol/L, respectively). Bioleaching experiment indicates that the strain can oxidize Fe(Ⅱ) efficiently, and after 30 d, 44.56% of copper and 95.31% of iron are extracted from chalcopyrite and pyrite, respectively.     

生物法制备聚合硫酸铁及其应用研究

研究生物法制备铁系絮凝剂及其影响因素。以FeSO4·7H2O为原料,利用驯化后的氧化亚铁硫杆菌（T·f）在酸性条件下的催化氧化作用制备生物聚合硫酸铁（PFS）,并确定最佳制备条件。实验表明：在反应液初始pH值1.5、硫酸铵用量0.5g/L、初始Fe2＋浓度45g/L、接种量10%、温度30℃时,在转速为120r/min的恒温水浴摇床中连续培养5～6d、可以制出pH1.5～2.2、盐基度17.5%～22.7%、全铁含量43.87～45.24g/L的产品。实验通过处理3种废水来考察其絮凝性能,结果表明：当PFS投加量一定时,COD去除率可达70%以上,脱色率达90%,Zn2＋去除率达99%,说明PFS是一种絮凝效果优异的水处理剂。