PCR-测序法分析铀生物堆浸过程中微生物群落结构变化特征

文章采用PCR-直接测序法研究了铀生物堆浸不同浸铀阶段(前期酸化、酸化、前期菌液淋洗、菌液浸铀)微生物群落结构的变化。采用试剂盒法提取了矿石样品中宏基因组DNA,以细菌的16S rDNA通用引物27F/1492R扩增16S rDNA片段,建立16S rDNA克隆文库。从每个处理结果中筛选100个阳性克隆,阳性克隆子直接送测序,用NCBI Blastn程序进行基因数据比对分析,结果表明:从前期酸化阶段到菌液浸出阶段,菌落多样性呈减弱趋势,对浸铀有直接或间接作用的嗜酸性微生物:嗜酸性氧化硫硫杆菌(Acidithiobacillus thiooxidans)、嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)等的含量呈增加趋势。在菌液浸出阶段,pH值低于最小值1.8时,细菌多样性较高,对浸铀有直接或间接作用的嗜酸性微生物丰度较低。说明嗜酸性微生物对铀的浸出可能有重要作用,生物堆浸过程中需要严格调控pH值。     

低温下非离子表面活性剂加速细菌浸出黄铜矿

为了提高中温菌氧化亚铁嗜酸硫杆菌(Acidithiobacillus ferrooxidans)在低温(8～10℃)下浸出黄铜矿的浸出速率和最终浸出率,研究了非离子表面活性剂(吐温-20、吐温.60、吐温-80)加速细菌浸出黄铜矿的作用.通过对浸矿溶液中铜的浸出率以及细菌浓度的测定来评价表面活性剂对氧化亚铁嗜酸硫杆菌浸出效果的影响.研究结果表明:3种吐温类表面活性剂在低温条件下对细菌浸出黄铜矿均有一定加速作用,其中吐温-20的加速浸出效果最好,其最佳添加量为0.01%,经过90天后最终浸出率可达49.87%.     

低品位硫化铜矿生物柱浸过程细菌种群结构及演替规律

利用分子生物学的PCR-DGGE(变性梯度凝胶电泳)分析技术和PCR-16S rDNA序列分析技术研究了以黄铜矿为主的低品位硫化铜矿中温硫杆菌柱浸过程中细菌种群结构、演替规律及与铜浸出率之间的关系. DGGE电泳图谱共6个条带中有5个条带对应的菌株16S rDNA序列与已知菌?嗜酸氧化亚铁硫杆菌A.f的同源性均为98%以上. 用9K固体培养基从柱浸浸出液中随机分离出3个纯菌株的16S rDNA序列,与已知菌A.f的同源性也均为99%,均证明该生物柱浸过程以A.f为优势菌种. 细菌柱浸的菌群演替发生在A.f同菌种内的各菌株之间. 柱浸前期易浸的次生硫化铜矿选择了02和05两条带所对应的A.f菌株,柱浸中后期难浸的黄铜矿则选择了01, 02, 03, 04, 06五条带所对应的A.f菌株.     

以黄铜矿为主的低品位硫化铜矿生物浸出体系中的细菌优势菌群

通过对以黄铜矿为主的低品位硫化铜矿中温硫杆菌生物浸矿体系的细菌优势菌群的研究,探讨了黄铜矿的细菌作用机理. 采用9K培养基从细菌浸出矿浆中分离出了14株中温硫杆菌,其浸矿能力都弱于分离前的自然混菌菌种,在浸矿过程中自然形成的混菌群落中各菌株之间存在着协同效应. 从上述菌株中随机挑选出氧化浸出能力有较大差异的YK8, YK12和YK14进行了16S rDNA克隆测序分析,显示它们与Acidithiobacillus ferrooxidans的同源性均达到99%,为嗜酸氧化亚铁硫杆菌. 由此说明该浸矿体系的优势菌群为嗜酸氧化亚铁硫杆菌,细菌氧化作用机理以直接作用为主. 各纯菌株对Fe2+的氧化率存在较大差异,对菌浸矿浆用不同能源诱导培养后的混菌浸矿能力有显著变化.     

氧化硫硫杆菌对难选恩施赤铁矿脱磷的影响

利用嗜酸性氧化硫硫杆菌(Acidithiobacillus thiooxidans, At.t)菌种,对含磷为0.90%的恩施高磷赤铁矿进行了微生物降磷实验. 对At.t浓度、培养基初始pH值和赤铁矿粒度对磷浸出效果的影响进行了系统研究. 结果表明,用At.t对高磷赤铁矿进行磷浸出的最佳工艺条件为：At.t浓度10%,培养基初始pH值4.0,赤铁矿粒度75 mm,在此条件下得到的磷磷浸出率高达71%,At.t具有较好的降磷效果.     

氧化亚铁硫杆菌能量代谢产物之间反应促进硫化矿细菌浸出

对照扫描电镜照片考察了底物对氧化亚铁硫杆菌T.ferrooxidans N1 能量代谢和菌体生长的影响,分析了硫化矿的生物浸出过程中T.ferrooxidans的能量代谢产物之间的反应作用.实验结果表明：T.ferrooxidans的硫代谢产H⁺为溶液中Fe²⁺氧化代谢提供了必需的酸性条件;同时破坏了硫化矿晶格向溶液里释放Fe²⁺和Cu²⁺,使生物浸铜得到产品成为可能;菌体能量代谢中间产物之间氧化还原反应加快了T.ferrooxidans代谢速率,减缓了Fe³⁺的水解反应,使硫化矿浸出过程能持续进行;T.ferrooxidans代谢产物之间的氧化还原反应是硫化矿细菌浸出过程的关键.     

生物反硝化脱氮碳源上微生物的多样性

为了研究废弃农作物作为反硝化脱氮处理的新型碳源和生物膜载体中微生物的多样性及微生物的群落结构,将玉米芯作为反硝化碳源和生物膜的载体伽置在河道中,采集同步脱氮过程中的玉米芯样品并提取微生物总DNA,使用细菌通用引物对(GC341F和518R)从总DNA中成功扩增出目标16SrDNA片段,然后对扩增的16SrDNA进行变性梯度凝胶电泳(DGGE)测定,对凝胶染色并进行条带统计分析和切胶测序.结果表明以玉米芯为载体的生物膜优势菌变化规律与生存环境的变化存在较好的相关性,当水体中溶解氧提高后,生物膜上的优势种群以好氧/兼氧的异养杆状细菌Bacillus为主.     

抑制剂对嗜酸氧化亚铁硫杆菌形态影响研究

在生物冶金中,因矿石成分不同,某些成分会对浸矿菌产生抑制作用而影响金属的浸出。为研究氟、钼对浸矿微生物的影响,本研究以氟化钠和钼酸钠为两种抑制剂,研究不同浓度的抑制剂对两株不同来源的嗜酸氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)的影响。采用扫描电镜观察经添加不同浓度的抑制剂培养基培养后的嗜酸氧化亚铁硫杆菌的细胞形态,发现在添加抑制剂的条件下,细菌细胞均发生了或轻或重的皱缩,但细胞长度与宽度基本无变化。从而得出两种抑制剂均对这种细菌产生了抑制作用,并且使其在形态上也发生了一些变化,但具体的抑制机理有待深入研究。     

A2/O工艺中微生物群落结构分析

通过PCR-DGGE技术对A2/O工艺中的微生物多样性进行了分析,以细菌和古细菌16s rRNA 基因通用引物530F/1490R对A2/O活性污泥中提取的细菌基因组DNA进行PCR扩增,扩增产物经纯化后用于变性梯度凝胶电泳(DGGE)分析.结果显示,A2/O工艺中活性污泥的微生物群落非常丰富,在好氧区微生物的种属达到19种,缺氧区为18种,厌氧区为15种;A2/O工艺不同单元都有一些各自的特有种属和共有种属,工艺中的微生物群落演替不明显,微生物群落相似性为71.4%,群落结构较为稳定.     

不同区域污水处理厂活性污泥中微生物菌落结构分析

结合纯种分离纯化和变性梯度凝胶电泳法（DGGE）分析了中国不同区域污水处理厂的曝气池中活性污泥的微生物群落结构及差异性。其中,可培养微生物经纯化后对16s rDNA片段进行PCR扩增并测序,在Blast中分析后构建系统发育树。分离培养得到的89种细菌大部分属于β-变形菌门（Bataproteobacteria）、γ-变形菌门（Gamaproteobacteria）和厚壁菌门（Firmicutes）。DGGE分析表明所有活性污泥样品中的菌种丰富度都很高,不同的样品中存在很多相同的条带,是属于所有活性污泥中共有的优势菌群,说明不同的活性污泥系统具有高度的生物相似性;每个地区的样品中也都含有自己的特异条带。并且同一地区活性污泥的相似性大于不同地区活性污泥的相似性,主要与各地区不同的自然经济环境和人们的生活习惯相关。     

氧化亚铁硫杆菌与中度嗜热铁氧化菌浸出铁闪锌矿的比较

考察了采用氧化亚铁硫杆菌和中度嗜热铁氧化菌浸出铁闪锌矿浮选精矿的浸出效果. 结果表明,两种细菌的驯化菌株都可以显著提高铁闪锌矿的溶解速率,且接种中度嗜热铁氧化菌时浸出效果更好. 扫描电镜、X射线粉晶衍射和能谱分析等表明,接种不同菌种浸出铁闪锌矿时所产浸渣具有类似的表面形貌特征和矿物组成. 可以证明,采用中度嗜热铁氧化菌浸出铁闪锌矿浮选精矿可以在较高的温度和酸度下进行且具有更好的浸出效果,比氧化亚铁硫杆菌具有更好的工业应用前景.     

铁闪锌矿细菌浸出过程中亚铁和细菌初始浓度的影响

利用摇瓶浸出研究了氧化亚铁硫杆菌在35℃下生物浸出铁闪锌矿的过程,探讨了铁含量和细菌接种量等因素对细菌在矿浆中的生长以及对锌浸出的影响,并对细菌浸出铁闪锌矿的机理进行了分析. 发现在不添加铁的情况下,即使细菌接种量达到40 mL,矿浆的氧化还原电位提高仍然非常缓慢,细菌无法在矿浆中正常生长,证明不存在直接浸出;而在添加FeSO4×7H2O的矿浆中,随接种量的增加细菌浸出铁闪锌矿的速度加快. 结果表明,铁闪锌矿的浸出需要一定量的Fe3+作为氧化浸出剂以提高浸出速度,因此必须预先添加部分Fe2+作为细菌氧化生成Fe3+的来源. 通过分析浸出过程中矿浆Eh和铁浓度的变化,认为Eh的高低与细菌浸出速度直接相关. 并且根据实验和电镜分析证明氧化亚铁浸出铁闪锌矿的过程是pH值上升的耗酸过程.     

Catalytic mechanism of manganese ions and visible light on chalcopyrite bioleaching in the presence of Acidithiobacillus ferrooxidans

The bioleaching of chalcopyrite is low cost and environmentally friendly,but the leaching rate is low.To explore the mechanism of chalcopyrite bioleaching and improve its leaching rate,the effect and mecha-nism of manganese ions (Mn2+) and visible light on chalcopyrite mediated by Acidithiobacillus ferrooxi-dans (A.ferrooxidans) were discussed.Bioleaching experiments showed that when both Mn2+ and visible light were present,the copper extraction was 14.38％ higher than that of the control system (with-out Mn2+ and visible light).Moreover,visible light and Mn2+ promoted the growth of A.ferrooxidans.Scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) analysis revealed that Mn2+ promoted the formation of extracellular polymeric substance (EPS) on the surface of chalcopyrite,changed the morphology of A.ferrooxidans,enhanced the adsorption of bacteria on chalcopyrite surface with light illumination,and thus promoted the bioleaching of chalcopyrite.UV-vis absorbance spectra indicated that Mn2+ promoted the response of chalcopyrite to visible light and enhanced the catalytic effect of visible light on chalcopyrite bioleaching.Based on X-ray photoelectron spectroscopy (XPS),the relevant sulfur speciation of chalcopyrite before and after bioleaching were analyzed and the results revealed that visible light and Mn2+ promoted chalcopyrite bioleaching by reducing the formation of pas-sivation layer (Sn2-/S0).Investigation into electrochemical results further indicated that Mn2+ and visible light improved the electrochemical activity of chalcopyrite,thus increasing the bioleaching rate.     

铁闪锌矿浮选精矿生物浸出

研究了氧化亚铁硫杆菌浸出铁闪锌矿浮选精矿的过程, 考察了正无菌、原菌种与驯化菌等条件下铁闪锌矿的浸出效果和矿浆浓度对矿物中有价金属浸出速率的影响. 摇瓶试验表明: pH值2.0、温度35 ℃、细菌接种量10%、矿浆浓度5%、矿石粒度<35.5μm(90%以上)和摇床转速160r&#8226;min^-1浸出条件下, 经过驯化的氧化亚铁硫杆菌能够显著地提高铁闪锌矿的溶解速率和浸出率;提高矿浆浓度导致铁闪锌矿中有价金属浸出率降低, 但单位时间内总的锌离子浸出量相应提高.     

酸浸及紫外诱变对氧化亚铁硫杆菌浸矿的影响

利用从湖北省大冶市铜山口矿区的酸性矿坑水中选育的氧化亚铁硫杆菌（Thiobacillus ferrooxidans,以下简称T.f菌）对该矿区的铁矿进行了浸矿研究。结果表明：未经酸浸处理的矿粉,对体系pH值的影响较大,从而影响T.f菌的生长,进而影响浸矿效果;经过酸浸处理的矿粉,在整个浸矿过程中,体系pH值相对恒定,T.f菌生长良好;对混合菌群进行单次紫外诱变,未能明显提高浸矿能力。     

Bioleaching of metal from waste stream using a native strain of Acidithiobacillus isolated from a coal mine drainage

In this study, the feasibility of using a biohydrometallurgical technique for selective metals recovery from electronic waste (e‐waste) by bacterial bioleaching was investigated. Acidithiobacillus was identified in coal mining acid mine drainage (AMD). The microorganism was studied using specific sequencing of a 16s rDNA fragment. The potential for the dissolution of copper from waste printed wire boards (PWBs) using the isolated Acidithiobacillus ferrooxidans (A. ferroxidans) was evaluated. The bioleaching experiments were performed in an orbital shaker at 30 °C and 170 rpm, with 10 % (v/v) inoculum and a pulp density of 30 g/L. The copper concentration was determined by energy dispersive x‐ray fluorescence (XRF). The result shows that copper recovery from PWBs using our A. ferrooxidans strain was 95 % after 8 days, which showed the feasibility of this process.     

Fe2(SO4)3溶液细菌辅助浸出高砷金精矿

利用摇瓶实验对纯Fe2(SO4)3溶液浸出高砷金精矿进行了研究,考察了温度及Fe3+浓度的影响,并与细菌直接浸矿进行了对比. 同时,在Fe2(SO4)3溶液中加入高密度嗜中温氧化亚铁硫杆菌、嗜中温氧化硫硫杆菌、中度嗜热西伯利亚硫杆菌,考察其对Fe2(SO4)3溶液的辅助浸出作用. 结果表明,Fe3+溶液化学浸出可迅速溶解高砷金精矿,随温度升高,浸出率先升后降,80℃时达最大;浸出前期Fe3+浓度的积累对浸出速率影响不大,初始Fe3+浓度越高As的浸出率越高,但当Fe3+浓度高于40 g/L,由于沉淀严重,浸出率降低;连续浸出情况下,Fe3+浓度可维持恒定,10 g/L的Fe3+可保持较快的矿物浸出速率. 对照实验表明,较高的矿浆浓度对浸矿菌生长繁殖有显著影响. 高密度浸矿菌可维持Fe2(SO4)3溶液中较高的Fe3+浓度并及时消除反应产生的S层的阻碍,有利于Fe2(SO4)3溶液对矿物的浸出.     

A Novel Approach to Bioleach Soluble Phosphorus from Rock Phosphate

A novel approach to bioleach soluble phosphorus from rock phosphate, involving the bio-oxidation of pyrite by adaptated Acidithiobacillus ferrooxidans (At. f) and the product of sulfuric acid to dissolve rock phosphate, has been proposed in this paper. The soluble phosphorus could be leached more effectively in the presence of pyrite by At. f than that leached directly by sulfuric acid. The optimal technological parameters are presented. The highest phosphorus leaching rate is 9.00% when the culture substrate is the mixture of FeSO4·7H2O and pyrite, the phosphorus leaching rate is 8.00% when the initial pH and culture time are 2.5 and 5 d, respectively. The optimal rock phosphate particle size is 0.05 mm for the leaching of phosphorus. The bigger the grains of pyrite, the lower the phosphorus leaching rate. The bacterium At. f should be appropriately adaptated, which makes it easier to bioleach soluble phosphorus from rock phosphate.     

黑曲霉菌一步浸取低砷硫化矿:Taguchi正交优化(英文)

A study was carried out to examine the possibility for Aspergillus niger strain KBS4 to bioleach metals from sulphide ore with low concentration of arsenic and to optimize the parameters that affect this process by orthogonal array optimization. Fungal sample was collected, purified and sequenced. The bioleaching process was optimized with L25 Taguchi orthogonal experimental array design. Five factors were investigated and 25 batch bioleaching tests were run at five levels for each factor. The parameters were initial pH, particle size, pulp density, initial inoculums and residence time for bioleaching. The experimental results showed that under optimized leaching conditions: pH 5.5, particle size 180 μm, initial inoculums size 3×10 7 spores per ml, pulp density 15% and residence time of 20 days, the bioleach ability of metals were 63% Fe, 68% Zn, 60% As, 79% Cu and 54% Al. The biosorption of metal ions by fungal biomass might occur during the bioleaching process but it did not hinder the removal of metal ions by bioleaching.