浸矿微生物的鉴定和计数的分子方法

本文介绍了浸矿微生物的鉴定和计数以及现场测试的分子方法，包括免疫学方法和分子生物学方法。推广和应用这些现代分子方法，对生物冶金领域的研究及生产实践皆具有重要意义。     

浸矿微生物研究中分子生物学技术应用进展

随着分子生物学研究的快速发展,越来越多的分子生物学技术被用于研究浸矿微生物。在浸矿微生物的分类鉴定工作中,DNA G+C含量测定和DNA/DNA杂交是常用的分子生物学方法,以PCR技术及其为基础的16S rRNA基因序列分析技术在分类鉴定中亦被广泛应用。同时,RFLP以及RAPD技术在浸矿菌种分类鉴定中也起到重要作用。另外,分子生物学技术还被用于揭示浸矿体系中微生物种群组成和群落演替,其中DGGE技术、SSCP技术、ISR技术、FISH技术、基因文库以及脉冲电泳等技术对于研究浸矿菌的群落组成、演替发挥重要作用。     

浸矿微生物分子生物学鉴定方法

介绍了微生物浸矿中,浸矿微生物的鉴定非常关键,它是对浸矿微生物进行驯化、诱变、基因重组等后续操作的基本前题以及目前分子生物学方法在浸矿微生物鉴定中的应用情况。认为DNA探针分析方法具有快速、灵敏、特异性高等特点,适合混合菌群中已知菌株的快速检出,可应用于未经培养的自然菌群中菌株的鉴定;16SrRNA序列分析方法结果比较准确。     

分子生物学技术在浸矿微生物研究中的应用

分子生物学技术在浸矿微生物的研究中发挥着举足轻重的作用。总结了一些先进分子生物学技术在浸矿微生物鉴定和浸矿微生物基因工程育种两方面的应用情况,包括16S rRNA和16S rDNA基因序列分析技术、实时定量PCR技术、限制性片段长度多态性分析技术、荧光原位杂交技术、变性梯度凝胶电泳和温度梯度凝胶电泳技术、基因间隔序列分析技术、浸矿微生物质粒载体研究、外源基因导入浸矿微生物方法研究等。     

浸矿微生物紫外诱变选育及浸矿机理研究

通过微生物的铜离子耐受性培养,选取可以浸出铜离子的酸性浸矿微生物,并利用紫外线照射对微生物进行诱变培养,培育出一种可以高效浸出铜离子的酸性浸矿微生物。同时探讨了微生物对铜离子的耐受性培育和紫外线诱变在高效浸矿微生物选育中的应用,以及浸矿微生物在矿山中的应用前景。     

生物浸矿领域中功能微生物的研究进展

微生物浸出技术是一种新型的环境友好型湿式冶金技术,可以作为解决高品位矿产储量缩减和尾矿堆存数量增加等难题的潜在有效途径。具有浸矿功能的微生物在生物浸矿过程中有着举足轻重的作用。根据浸矿微生物的营养代谢类型可以将微生物分为自养代谢微生物和异养代谢微生物2大类,归纳总结了不同类型微生物在生物浸矿过程的最佳浸矿条件、浸出效率和浸出机理。自养微生物主要用于浸出硫化矿,其中氧化亚铁硫杆菌应用最为广泛,且混合菌的浸出效率高于单一菌的浸出效率;而异养微生物主要用于浸出非硫化矿,介绍了硅酸盐细菌、产氨细菌和真菌在浸矿领域中的功能。在此基础上,提出了高效浸矿功能微生物未来存在突破可能的研究角度：原位驯化与分离筛选功能微生物、构建与应用基因工程菌株、设计与优化特异性培养基、推进异养浸矿微生物的深入研究与实际应用、菌群共代谢调控及菌剂研发等。     

硫化矿生物冶金研究进展

对硫化矿生物冶金进行了较全面的综述，包括浸矿微生物种类及培养条件、硫化物细菌氧化机理、氧化亚铁硫杆菌的铁硫氧化系统、浸矿工艺、影响浸矿效果的主要因素以及浸矿细菌的分子生物学。介绍了国内外生物冶金的工业化应用现状。提出了我国硫化矿生物冶金需要解决的主要问题。     

细菌浸矿作用分析

归纳总结硫化矿细菌浸出过程的各类作用过程，综述相关研究结果。细菌的存在使矿物表面的H^ 浓度增加，同时也使体系混合电位上升。直接作用和间接作用的区别在于硫化矿的氧化分解是否通过Fe^3 的氧化作用，即不管细菌粘附矿物与否，间接作用为Fe^3 浸出矿物，而直接作用则指细菌的直接氧化分解作用。细菌浸矿过程是包括化学、电化学、动力学现象的复杂过程，各种作用不是孤立的，是互相联系，互相影响的。     

微生物胞外聚合物在浸矿过程中作用的研究进展

综述国内外学者对浸矿微生物的胞外聚合物的研究进展.胞外聚合物是革兰氏阳性菌和革兰氏阴性菌细胞分泌的不同种类的生物聚合物,是生物膜中围绕在细菌周围的高度含水的多聚大分子.不同细菌的胞外聚合物组成和物理化学属性不同,决定着生物膜的粘附、构型及生物学特性.     

硫化矿的生物冶金及其研究进展

生物冶金由于其生产成本低、投资少、工艺流程短、设备简单、环境友好、能处理复杂多金属矿物等优点,今后可望在湿法冶金中起到更大作用.目前,生物冶金技术已广泛应用,并在铜的提取上实现了工业应用,同时科学工作者对于生物冶金中的微生物及生物浸出过程的机理展开了大量研究工作.本文较系统地介绍了国内外生物冶金的发展概况,归纳了关于浸矿微生物的种类及其作用的研究状况,讨论了微生物冶金过程的直接作用、间接作用,论述了细菌浸出过程的原电池效应及硫化矿氧化过程电化学机理的研究,归纳了关于硫化矿生物冶金的研究进展.     

铜萃取界面乳化液中浸矿微生物的多样性

界面乳化是溶剂萃取过程中难以避免的现象,显微观察发现在铜萃取界面乳化液中存在形貌复杂多样的微生物。利用16s rRNA基因测序技术对铜萃取界面乳化液中微生物种群结构进行分析,结果发现包括Leptospirillum sp,Acidithiobacillus ferrooxidans,Metallibacterium sp,Staphylococcus sp在内的7类细菌,其中优势菌种为Leptospirillum sp.E4-L9和Acidithiobacillus ferrooxidans ATCC 23270,两者在乳化液细菌中分别占到40.48%和38.1%。利用Fe2+和硫作为能源对界面乳化液中的微生物进行分选,进一步分析种群结构。铜萃取界面乳化对浸矿细菌有截留作用,从而会降低生物浸矿效率。     

Some aspects of the effect of pH and acid stress in heap bioleaching

The chemical and physical conditions in sulphide heaps provide a complex environment for micro-organisms, with differences in redox potential, acidity, temperature, oxygen and solution chemistry conditions being experienced both temporally and spatially. One of the most important parameters for successful microbial colonisation and active microbial metabolism is suitable pH conditions in the heap. Typically heaps reach tens of metres high and the pH of irrigation solution travelling through heap changes significantly.In this study, we investigated the effect of pH and acid stress for moderately thermophilic and thermophilic mixed cultures, operating at 50-60 °C in a heap bioleaching environment. Results collected from laboratory scale column reactors packed with the low grade whole ore and irrigated with different pH solutions during a temperature shift from moderately thermophilic conditions to thermophilic conditions are discussed.     

微生物浸矿技术在处理低品位铜矿中的现状及发展趋势

介绍了国内外微生物浸矿技术的发展和应用现状、浸矿微生物的种类和特性、浸矿机理,并对微生物浸出技术处理低品位铜矿石的发展趋势进行了展望。     

The effect of potential heap construction methods on column bioleaching of copper flotation tailings containing high levels of fines by mixed cultures

It is known that excess fines may reduce heap permeability and block channelings of leachate flow in heap bioleaching operation, and further cause low metal recovery. The purpose of this investigation was to compare the effects of three potential heap construction methods including layered heap construction method (Method A), agglomerate heap construction method (Method B) and pelletized sintering heap construction method (Method C) of copper flotation tailings on column bioleaching behaviors. In the three heap construction methods, the tailings copper extractions achieved 54.61%, 60.09% and 43.93%, respectively, in Method A, B and C on day 83. Copper extraction of Method B reached maximum. In addition, compositions and structures of microbial communities were examined using Illumina Miseq sequencing technology based on 16S rRNA amplification. Acidithiobacillus, Leptospirillum and Ferroplasma were main microorganisms in three heap construction methods. Detrended correspondence analysis showed that Method C had little effect on microbial communities. These studies revealed the influence of different heap construction methods on leaching behaviors and microbial dynamics, which will facilitate the bioleaching of fine-grained ores.     

The effect of redox control on the continuous bioleaching of chalcopyrite concentrate

A continuous bioleaching process was developed for the dissolution of chalcopyrite concentrate with electrochemically redox control. Therefore, using a flotation concentrate containing 46% chalcopyrite and 23% pyrite, bioleaching tests were carried out at 47 °C with 15% pulp density under controlled and uncontrolled redox conditions. To increase the copper recovery in contrast to the conventional bioleaching (∼39.62%), the effect of redox potential on the chalcopyrite bioleaching was investigated by electrochemically controlled bioleaching. The results showed that by controlling the redox potential, faster copper leach kinetics could be achieved. At last, reducing the redox potential from high levels to optimum window (420–440 mV SCE) caused an increase in copper recovery from around 39% to higher than 69% (over 25 g/L Cu²⁺).     

Investigating the effect of acid stress on selected mesophilic micro-organisms implicated in bioleaching

During start-up of heap bioleaching, low grade ores may be treated with acid for agglomeration and to combat the acid neutralising capacity of the gangue minerals. This may stress the bioleaching inocula, particularly upon inoculation during ore agglomeration. Acid addition for agglomeration varies across operations, ore types and their neutralising capacity, with limited information published on recommended concentrations. The initial pH in the agglomeration mix is typically below pH 1.0 and may be as low as pH 0.5.This paper investigates the effect of acid stress in terms of initial acid concentration and duration of exposure in submerged culture on mesophilic micro-organisms typically implicated in mineral sulphide bioleaching and critical for heap colonisation at start-up. Following acid stress, cultures were returned to standard operating conditions in batch stirred slurry reactors and their performance assessed in terms of mineral leach rates, ferrous oxidation and the rate of microbial growth. Increasing acid stress resulted in an increase in the lag period before onset of microbial growth and iron oxidation due to decreased viable cell numbers, specific metabolic activity or both. Following adaptation, typical growth and ferrous iron oxidation rates were observed under low stress conditions while reduction in the rate and extent of microbial growth and ferrous iron oxidation persisted at extreme conditions. A reduction in yield (microbial cells produced per kg iron oxidised) was observed with increased acid concentration over comparative times. Microbial speciation analysis indicated a substantial decrease in the diversity of the microbial species surviving.     

嗜酸性浸矿菌对不同外源黄铁矿的利用率研究

某矿床铀矿石中黄铁矿含量较低,为提高矿石的生物可浸性,需选择并添加一种便于浸矿菌利用的黄铁矿。本文利用某铀矿富集得到的嗜酸性浸矿菌B3mYP1Q-C,对3种不同产地的黄铁矿进行黄铁矿利用摇瓶试验,试验所用混合菌群B3mYP1Q-C对选取的3种外源黄铁矿均可利用,但利用率差别较大,江西某铜矿黄铁矿精矿的利用率最高;同时,经过设置添加含氟矿石对照试验组,证明了含氟铀矿石会影响微生物菌种活性,亦会降低微生物对黄铁矿的利用能力。     

中温嗜酸硫杆菌浸出低品位硫化铜矿

研究了中温嗜酸硫杆菌的生长条件, 对黄铜矿进行了细菌浸出试验研究。研究表明, 中温嗜酸硫杆菌最适宜的生长条件为: pH值为2, 温度为30±1 ℃, 此条件下细菌浓度为2.24×10⁷个/mL。接种量、矿浆浓度对黄铜矿中铜的浸出率有显著的影响, 随着接种量的增加, 铜的浸出率提高。在相同浸出时间内, 矿浆浓度5%左右时, 黄铜矿中铜的浸出率最高。低品位硫化铜矿柱浸试验结果表明: 细菌浸出75 d, 铜的浸出率为45%。     

Possibilities for Co(III) dissolution from an oxidized ore through simultaneous bioleaching of pyrite

Solubilisation of Co(III) from a heterogenite met in copper cobaltiferous oxide ore has been realized through reductive leaching using ferrous iron generated via bio-oxidation of pyrite. Biotic and abiotic experiments at various pulp densities and redox potentials have been performed and results compared. Cobalt leaching at elevated redox potential is possible, offering cost reduction benefits due to reduced consumption of ferrous iron. At elevated potential of 625 mV, however, the initial rate of cobalt leaching has been found as 115 mg/(g ore)⋅(24 h), lower than the rate of 865 mg/(g ore)⋅(24 h) registered at 505 mV. Less stochiometric amount of ferrous iron was required when cobalt leaching was coupled to pyrite bioleaching, with 75% of cobalt recovered for 12 h at the optimally found conditions. It could be inferred that the Fe³⁺–Fe²⁺ cycle exists and is efficiently maintained through bacterial presence in the studied system.