细菌化学诱变育种对富钾砂页岩生物浸矿提钾的影响

以多黏芽孢杆菌P.Polymyxa(PA)和根瘤农杆菌A.tumefaciens(AT)为出发菌株,采用硫酸二乙酯(DES)对其进行诱变育种与浸矿研究。结果表明:分别通过30和40 mg/L的DES处理出发菌株PA和AT,致死率分别为87%和85%,正突变率分别为10%和16%;筛选获得的两株突变菌PAM和ATM达到生长稳定期的时间分别比对应的出发菌株缩短了48和24 h,且具有更大的菌体密度以及产酸和产蛋白质与多糖的能力;浸出15 d,诱变菌株PAM和ATM从富钾砂页岩中释放的K2O量分别比对应的出发菌株提高了29.00%和21.28%,且达到浸出终点的时间分别提前了5和3 d;混合诱变菌株浸出的K2O的量比单一诱变菌株PAM和ATM浸出的K2O的量分别提高了22.78%和67.55%,且达到浸出终点的时间比出发菌株的提前了6 d;SEM和XRD分析结果表明:混合诱变菌株对富钾砂页岩的破坏作用最为明显;在富钾页岩混合菌浸矿过程中,P·Polymyxa为浸矿优势菌种,诱变前后混合菌浸出15 d后,P.Polymyxa和A.tumefaciens的菌落个数比由最初的1:1分别变为7:1和18:1。     

源自硫化矿区的Acidiphilium属菌的分离及其浸矿性能

从湖北大冶铜矿的铜山口硫化矿矿坑水中分离得到了一株嗜酸兼性异养细菌,暂命名为DY.该菌株为革兰氏阴性细菌,短杆状,菌体大小为(0.4±0.1)μm×(1.2±0.2)μm,最适生长温度为30 ℃,最适初始生长pH值为3.5,能利用葡萄糖、乳糖、蔗糖和单质硫生长,不能利用FeSO4进行生长.其系统发育树结果表明,菌株DY与Acidiphilium cryptum(Y18446)位于系统发育树的同一分支中,相似度为99.69%.黄铜矿(CuFeS2)摇瓶细菌浸出实验显示,DY菌株单独浸出黄铜矿的能力较弱,但和嗜酸自养的氧化亚铁硫杆菌ATCC 23270混合浸矿时,与氧化亚铁硫杆菌单独浸矿相比,30 d后黄铜矿的浸出率提高了35.98%.     

混合高温菌浸出黄铜矿及浸出过程中微生物群落的演替

研究3株极端嗜热古菌(金属硫叶菌,Sulfolobus metallicus JCM 9184;瑟杜生金属球菌,Metallosphaera sedula JCM 9185和万座酸菌,Acidianus manzaensis YN25)在不同起始pH值和不同温度条件下对黄铜矿的混合浸出,并对浸矿过程中混合菌群落的动态演替进行分析.结果表明:在起始pH 1.5时的铜浸出率明显高于在起始pH 2.5时的铜浸出率,而65 ℃条件下的铜浸出率高于75 ℃时的铜浸出率.利用限制性长度多态性(RFLP)分析65 ℃、起始pH 1.5条件下的微生物群落演替,结果显示:在黄铜矿的浸出前期Sulfolobus metallicus是占据优势的菌种,而到后期Acidianus manzaensis的比例则会上升,并最后取代Sulfolobus metallicus成为优势种.     

细菌亚硝酸钠诱变育种及铝土矿浸矿脱硅

以胶质芽孢杆菌CGMCC11和环状芽孢杆菌CGMCC12为出发菌株,采用亚硝酸钠对其进行诱变育种与浸矿研究。结果表明:菌株CGMCC11和CGMCC12的最适生长温度分别为28和30℃,最适pH值分别为7.2和8.3。采用40和60 mg/L亚硝酸钠分别处理出发菌株CGMCC11和CGMCC12,致死率分别为87%和85%,正突变率分别为18%和20%;筛选获得两株突变菌CGMCC11KP和CGMCC12KP,其达到生长稳定期的时间分别比对应的出发菌株达到生长稳定期的时间缩短了48和24 h,且具有更大的菌体密度、产酸和产大分子胞外聚合物的能力。浸矿15 d,与对应的出发菌株相比,突变菌株CGMCC11KP和CGMCC12KP溶出的SiO2量分别提高了30.47%和29.57%,且达到浸出终点的时间分别提前了5和3 d;混合诱变菌株浸出液中SiO2的量分别比对应的诱变菌株浸出液中SiO2的量提高了20.0%和37.5%,且达到浸出终点的时间比出发菌株达到浸出终点的时间提前了6 d。SEM和XRD结果表明:混合诱变菌株对铝土矿的溶蚀分解最为明显,混合浸出15 d后,诱变前后胶质芽孢杆菌CGMCC11和环状芽孢杆菌CGMCC12的菌落个数比由1:1变为10:1。     

两种极端嗜热古菌对黄铜矿的吸附和浸出行为（英文）

研究两株具有代表性的极端嗜热古菌A. brierleyi和S. metallicus及其混合物对黄铜矿的吸附和浸出行为。结果表明,S.metallicus的铜浸出率略高于A.brierleyi的,其中混合菌体系的铜浸出率最高。浸出过程中的群落结构分析表明,S. metallicus在菌群中属于优势菌群;A. brierleyi所占比例呈现上升趋势,而这一上升趋势与黄铜矿在混合体系浸出后期的铜浓度比在单菌体系增长更快有关。Langmuir参数分析得出两种古菌之间不存在竞争性吸附关系,而qPCR结果显示,在混合浸出的过程中,S. metallicus和A. brierleyi之间会产生促进性吸附。本研究进一步阐明混合极端嗜热菌在矿物表面上所发生的吸附行为。     

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%)。     

混合中度嗜热微生物浸出两种不同类型低品位铜尾矿的比较研究（英文）

利用混合中度嗜热微生物浸出比较研究两种不同类型的低品位铜尾矿(酸浸尾矿和铜浮选尾矿)在浸出过程中矿物学和微生物学特征的变化。结果表明:两种尾矿的浸出行为具有很大的区别。与铜浮选尾矿相比,酸浸尾矿的浸出液中氧化还原电位较低,[Fe3+]/[Fe2+]的比例和微生物菌体密度较高,导致总铜、原生硫化铜和次生硫化铜的浸出率增加。XRD结果表明,在浸出浮选尾矿中,检测到石膏和金属有机复合物,这些物质会减缓硫化矿物的氧化过程。两种尾矿浸出过程的微生物群落变化明显:酸浸尾矿浸入过程中铁氧化菌的比例高于浮选尾矿浸出的,但硫氧化菌比例低于浮选尾矿浸出的,浸出酸浸尾矿时可以检测到F. thermophilum L1,但在浸出浮选尾矿中检测不到。     

微生物浸出Pb-Zn-Sn黄铜矿及其生物群落的演替分析

研究了Pb-Zn-Sn黄铜矿精矿在混合中度嗜热微生物槽浸过程中的细菌群落结构变化,并监测浸出体系中金属离子浓度、溶液电位、溶液pH值变化,通过聚合酶链式反应-限制性片段长度多态性（PCR-RFLP）技术分析微生物群落的结构变化。结果表明,最终铜浸出率高达85.6%,在浸出前期,Acidithiobacillus caldus为优势群落,从第18天开始到浸出结束,Sulfobacillus thermosulfidooxidans为优势群落,但Leptospirillum ferriphilum丰度变化较小。试验结果表明,适当较高的溶液电位和合适的铁离子浓度对黄铜矿精矿的生物浸出作用很关键。     

本地混合菌群微生物氧化难处理含金硫化精矿（英文）

采用含铁氧化菌和硫氧化菌的混合嗜中温菌群浸出阿根廷Andacollo矿的含金硫化浮选精矿。实验在摇瓶中进行,矿浆浓度为10%,采用pH 1.8的含亚铁离子的基础盐溶液作为介质。采用不同的方法对浸出液的pH值、氧化还原电位、亚铁离子和总金属浓度进行测定。结果表明,该种混合菌能够很好地还原浸出该难处理金矿,金的回收率可达91.6%,同时,铜和锌的浸出率也较高。动力学研究表明金属的溶解符合收缩核模型。其中,铜的溶解速率受生成产物层的扩散控制,而锌的溶解没有明显的控制步骤。     

铜镍氧硫混合矿焙烧-浸出过程铜、镍、铁的转化

随着硫化镍矿资源的日趋枯竭,铜镍氧硫混合矿的利用将会愈发受到关注。通过对原矿进行差热-热重、XRD以及热力学分析,揭示焙烧过程矿石矿相的转变历程,研究铜镍氧硫混合矿焙烧过程中矿物粒度、焙烧温度和焙烧时间对铜、镍、铁转化的影响,探索浸出过程中溶剂、液固比、浸出温度及浸出时间对铜、镍、铁浸出的影响。结果表明:矿物粒度为74~80μm、焙烧温度为600℃、焙烧时间为2 h、选择水作为浸出溶剂、浸出温度为60℃、液固比为6:1、浸出时间2 h时,镍和铜的浸出率达到最高分别为46.25%和96.27%,铁的浸出率低于1%。     

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.     

Comparative study on bioleaching of two different types of low-grade copper tailings by mixed moderate thermophiles

The bioleaching of two different types of low-grade copper tailings, acid-leaching tailings (ALT) and copper flotation tailings (CFT) by mixed moderate thermophiles, and the variation of mineralogical and microbiological characteristics during their dissolution processes were comparatively investigated. Results showed that bioleaching behaviors of the two types of tailings were significantly different. In ALT bioleaching, lower redox potential, higher [Fe³⁺]/[Fe²⁺] ratio and higher cell density in solution were obtained. These resulted in higher total copper, primary copper sulfide and secondary copper sulfide extractions, compared with CFT bioleaching. X-ray diffraction analysis suggested that gypsum and some metal organic complexes were detected in CFT bioleaching, which could cause the sluggish oxidation of sulphide minerals. The shifts of microbial community in the leachates and leaching residues varied greatly between ALT and CFT bioleaching. The percentage of iron-oxidizing bacteria in ALT bioleaching was higher than that of CFT, but the sulfur-oxidizing bacteria percentage was the opposite. The archaeon F. thermophilum L1 was detected in ALT but not in CFT.     

黄铁矿、单质硫、亚铁离子对浸矿微生物产生胞外多聚物的影响(英文)

嗜酸浸矿微生物产生的胞外多聚物(EPS)在酸性矿坑水的产生和硫化矿的浸出过程中,有着非常重要的影响,胞外多聚物(EPS)介导细胞与能源物质的接触,对有机薄膜的形成和细菌与基础物之间的相互作用起着重要的作用。对7株浸矿菌在不同能源培养物下产生的EPS的量以及EPS的化学成分进行研究,发现EPS含有化学成分糖、蛋白质、糖醛酸等,细菌的种类和能源物质对EPS的量和成分有很大影响。结果表明,以黄铜矿为能源物质的细菌产生的EPS要比以单质硫和亚铁为能源物质产生的EPS量多,EPS含量最高为(159.43±3.93)mg/g,是由Leptospirillum ferriphilum CBCBSUCSU208015在黄铁矿为能源物质下产生的。     

Microbial community structure and function in sulfide ore bioleaching systems

The severe current situation facing to minerals processing is that the most minerals are characterized by low-grade, being complex and very hard to deal with. It is necessary to find a new way to solve these questions. Nowadays, biohydrometallurgy draw more and more attention because of its simple process, low cost and kindness to environment. However, the lack of suitable bacteria and hard research on the mechanisms between the bacteria and ores or bacteria in gene level result in the low efficiency and poor yield of the target metal in bioleaching. Therefore, the understanding of the microbial community structure and function in the bioleaching systems is very important for the optimization of microbial community by controlling the operating conditions in bioleaching systems, thus enhancing the leaching rate. A review is given on the achievements and progress related to the study on microbial community structure and function in sulfide ore bioleaching systems made in our research group.     

低品位硫化铜矿的细菌浸出

以宁夏某低品位硫化铜矿为研究对象,利用嗜酸氧化亚铁硫杆菌(Acidithiobacillusferrooxidans)和嗜酸氧化硫硫杆菌(Acidithiobacillusthiooxidans)的混合菌,采用摇瓶浸出、小型柱浸和大型柱浸对矿石可浸性进行研究;采用X射线衍射仪分析矿物及其浸渣的成分;采用扫描电镜分析浸渣表面形貌及其表面元素的含量.结果表明摇瓶矿浆浓度为5%,浸出55d铜浸出率为94.38%;小型柱浸处理矿石2.10kg,矿石粒度小于15mm,浸出226d铜浸出率为62.50%;大型柱浸处理矿石77.85kg,矿石粒度小于25mm,浸出285d铜浸出率为50.63%.柱浸过程中,铜的浸出速率逐渐下降;浸渣中钙含量基本不变,而元素硫的含量明显增加,且存在新的石膏相;浸出后矿石表面元素硫、钙、铁的含量明显增加,在浸出过程中生成的硫酸钙结晶覆盖在矿石表面,铁在矿石表面形成沉淀,使矿石的渗透性变差,导致铜的浸出率逐渐下降.     

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.     

伊朗Kooshk铅-锌尾矿坝闪锌矿的生物浸出

将取自伊朗Yazd省Kooshk铅-锌尾矿坝的闪锌矿样进行生物浸出,并对比研究不同条件下的锌浸出率。Kooshk铅-锌尾矿坝含有3.64%锌、0.97%铅和24.18%铁。先将混合嗜温菌株、混合中度嗜热菌株进行摇瓶培养,然后在9K培养基中再次培养。在浸出闪锌矿的14 d 内,在有菌株的情况下,闪锌矿的浸出率达90%,而没有菌株的情况下,只有44%的闪锌矿被浸出。实验结果表明,在有菌株浸出的前10 d,有没有9K培养液对锌的浸出率有明显影响,但随后其差别不明显,到最后趋于相同。锌浸出率的提高与细菌菌落数和Fe3＋浓度的增加有关。中度嗜热菌浸取锌的动力学要求明显高于嗜温菌的,因此,在中度嗜热菌株存在的情况下,在低的氧化电位下闪锌矿优先于黄铁矿溶解而被浸出。