【作者】 钱林；

【导师】 杨宇； 邹俐宏；

【作者基本信息】 中南大学 ， 微生物学， 2008， 硕士

【摘要】 生物冶金是一种从利用微生物从矿物中提取有价金属的经济方法,特别适于处理贫矿、表外矿及废矿,并具有成本低、投入小、能耗低、对环境污染小等突出优点。在生物冶金中,对高效浸矿菌种的选育和机理研究意义重大。在本文研究中,从金属硫化矿区酸性矿坑水（AcidMine Drainage,AMD）中分离纯化得到多株具有浸矿功能自养的嗜酸氧化亚铁硫杆菌（Acidithiobacillus ferrooxidans,简称A.f）和兼养的嗜酸杆菌（Acidiphilium spp.）。随后,从这两种菌的分离、鉴定出发,分别对其生理生化特征和浸矿能力进行了研究,同时考察了它们单独及混合浸出黄铜矿的能力,初步探讨了细菌混合浸矿的协同机理。首先,本文从广西高峰,湖南浏阳,广东大宝山,江西德兴的酸性矿坑废水中分离得到四株嗜酸氧化亚铁硫杆菌:GF,LY,DBS,DX。其最佳生长温度为30℃,最佳初始生长pH为2.0,化能自养,能利用亚铁、单质硫和葡萄糖生长,不能利用硫代硫酸钠、蛋白胨生长。对四个菌株的亚铁和硫的氧化能力进行研究,发现不同样点筛选得到的菌株之间的氧化活性存在明显差异,同时四株细菌的亚铁氧化活性和硫氧化能力强弱一致,均为GF＞LY＞DBS＞DX。选取其中氧化活性最高的菌株GF进行摇瓶浸出铁闪锌矿实验,浸出30天后,细菌浸出的锌离子浓度达到7302.5 mg/L,而无菌对照中锌离子浓度只有273.2 mg/L。菌株GF浸出铁闪锌矿效果十分明显,能极大的提高铁闪锌矿的浸出率。其次,本文从取自全国8个不同矿山的酸性矿坑废水中分离纯化得到25株嗜酸兼性异养的Acidiphilium spp.细菌。随后,对其中一株DY菌株进行生理生化研究,其最适生长温度为30℃,最适初始生长pH为3.5,该菌具有广泛的底物利用特性,能利用葡萄糖、乳糖、蔗糖等多种有机物,及其单质硫和多种硫化矿生长,不能利用FeSO₄进行生长。同时对上述25株Acidiphilium spp.细菌进行生态多样性分析研究发现,相比16S rRNA基因,通过gyrB基因构建的系统发育树能够区分一些16S rRNA基因无法区分的种类。最后,通过摇瓶浸出和反应器柱浸黄铜矿研究发现,虽然Acidiphilium sp.菌DY单独浸出黄铜矿效果不佳,但当和嗜酸自养的氧化亚铁硫杆菌混合浸出时,相比氧化亚铁硫杆菌单独浸矿,两者混合浸矿时能显著提高黄铜矿的浸出率。初步探讨其原因是在混合浸出黄铜矿的过程中,自养的氧化亚铁硫杆菌和异养菌的Acidiphilium spp.之间对矿物存在协同效应,一方面减缓在浸矿过程中黄铜矿表面钝化膜的形成,另一方面阻止浸矿体系中对氧化亚铁硫杆菌的生长起抑止作用的有机化合物的积累,从而提高了黄铜矿的浸出效果。更多还原

【Abstract】 Bioleaching is an economical method for the recovery of metals from minerals,especially from low grade ores,overburden and waste from current mining operations,which requires moderate capital investment with low operating cost.Furthermore,bioleaching is generally more environmentally friendly than conventional metal recovery processes such as concentration and smelting.In the present study, several autotrophic bacteria Acidithiobacilius ferrooxidans and heterotrophic bacteria Acidiphilium spp.were isolated and characterized from Acid Mine Drainage（AMD）.This research worked on the isolation、physiological and bioleaching characterization of Acidithiobacilius ferrooxidans and Acidiphilium spp..To understand the role of autotrophic and heterotrophic bacteria plays in mineral bioleaching,we focused on the effects of one autotrophic iron and sulfur-oxidizing bacterium A.ferrooxidans GF and its synergistic effect with one heterotrophic sulfur-oxidizing bacteriam Acidiphilium sp.DY on copper dissolution from chalcopyrite.We isolated four autotrophic bacterial Acidithiobacilius ferrooxidans strains from different mining tailings in China,named as GF、LY、DBS and DX.The optimum growth temperature is 30℃,and the optimum growth pH is 2.0.The four strains can grow autographically by using Fe²⁺, sulfur,glucose as sole energy sources,however,can not grow with NaS₂O₃ and peptone.The data of ferrous sulfate and sulfur oxidation of four strains revealed that the activity of them is consentaneous.The relationship is consistent with the ferrous sulfate and sulfur oxidation activity of the four strains,GF＞LY＞DBS＞DX.Because of the high activity of oxidation ferrous and sulfide mineral,strain GF was used in bioleaching of marmatite.The Zn concentration was 273.25mg/L under the steriled control and 7302.5mg/L with adapted GF strain incubated after 30 d in leaching marmatite.The isolated strain GF can be used for leaching marmatite in industry application.25 acidophilic heterotrophic Acidiphilium-like bacterial strains were isolated from eight different mines in China and their physiology was characterized.The optimum growth temperature is 30℃,and the optimum growth pH is 3.5.It can grow facultative heterotrophically by using glucose,lactose,sucrose and elemental sulfur as sole energy sources,but can not grow with FeSO₄.The comparison of 25 Acidiphilium spp.bacterial results by 16S rRNA gene and gyrB gene analysis shows that gyrB gene analysis may provide more accurate information about the microbial community structure than 16S rRNA gene analysis and thus more likely to revealed the true nature of a microbial community.The bioleaching experiment of chalcopyrite in shake flasks and bioleaching column revealed that the acidophilic heterotrophic Acidiphilium sp.DY strain had little efficiency of leaching chalcopyrite, but when coupled with acidophilic autotrophilic bacteria A.ferrooxidans GF,compared with Aferrooxidans GF leaching efficiency,it can increase the chalcopyrite leaching efficiency greatly.Acidiphilium sp.DY has the potential role to enhance the recovery of copper from chalcopyrite by oxidizing the sulfur and reducing the organic compound during the bioleaching progress.The combination of the acidophilic heterotrophic Acidiphilium spp.and acidophilic autotrophilic A.ferrooxidans in chalcopyrite bioleaching improved the copper leaching efficiency.更多还原