Isolation of Leptospirillum ferriphilum by single-layered solid medium

According to physiological and biochemical characteristics of Leptospirillum ferriphilum,a strain of object bacteria was isolated successfully.Bacteria were enriched by selective liquid medium and plated on designed single-layered agar solid medium.Colony was cultured and bacteria were collected.The morphologies of the object bacteria were observed using crystal violet staining,scanning electron microscope(SEM)and transmission electron microscope(TEM).The result of 16S rDNA identification shows that this bacterium belongs to Leptospirillum ferriphilum and it is named as Leptospirillum ferriphilum strain D1.These results indicate that this new single-layered agar solid medium is efficient and simple for isolation of Leptospirillum ferriphilum.Additionally,physiological-biochemical characteristics show that the optimum initial pH value and its growth temperature are 1.68 and 40 ℃,respectively.The culture of it is used to leach a complex concentrate chalcopyrite,the leaching efficiencies of copper and iron are 1.93 % and 13.74 %,respectively,and it is more effective than the A.ferrooxidans culture in the leaching of the complex concentrate chalcopyrite.     

Growth kinetics of Thiobacillus ferrooxidans in bioelectrochemical cell

Thiobacillus ferrooxidans might be the most important bacteria used in biometallurgy. The foundation way of its growth process is oxidizing ferrous in order to obtain energy needed for metabolism, but the variation of ferrous concentration and mixed potential of the culture media would have crucial effect on the bacteria growth. Based on the characteristics of Thiobacillus ferroxidans growth and redox potential of ferric and ferrous, an electrochemical cell was designed conventionally to study growth rule and the relationship between redox potential and bacteria growth was built up, and some growth kinetics of Thiobacillus ferrooxidans were elucidated. It demonstrates that the variation of open potential of electrochemical cell ΔE shows the growth tendency of Thiobacillus ferrooxidans, at the initial growth stage, the value of δE increases slowly, when at logistic growth stage, it increases drastically, and the growth rate of bacteria is linear with the oxidation rate of ferrous. The bacteria growth kinetics model is proposed using Monod and Michealis-Menten equation, and the kinetics parameters are got. The consistence of the measured and the calculated results proves that it is proper to use the proposed kinetics model and the electrochemical cell method to describe the growth rule of Thiobacillus ferrooxidans. Foundation item: Project (50204001) supported by the National Science Foundation of China     

A Series Piezoelectric Quartz Crystal Response Kinetics for T.ferrooxidans Growth in the Presence of Cu(Ⅱ)

Ｉｎｂｉｏｈｙｄｒｏｍｅｔａｌｌｕｒｇｙ ,Ｔ .ｆｅｒｒｏｏｘｉｄａｎｓｉｓｏｎｅｏｆｔｈｅｍｏｓｔｉｍｐｏｒｔａｎｔｍｉｃｒｏｏｒｇａｎｉｓｍｓ[1]ｆｏｒｔｈｅｅｘｔｒａｃｔｉｏｎｏｆｂａｓｅｍｅｔａｌｓｉｎｃｌｕｄｉｎｇｃｏｐｐｅｒ[2～ 4 ],ｎｉｃｋｅｌ[5,6 ],ｚｉｎｃ[7],ｌｅａｄ[8]ｅｔｃ ,ａｎｄｔｈｅｐｒｅｔｒｅａｔｍｅｎｔｏｆａｒｓｅｎｉｃｒｅｆｒａｃｔｏｒｙｇｏｌｄｏｒｅｓ[9～ 12 ].ＴｈｅｓｔｕｄｉｅｓｏｎｔｈｅｇｒｏｗｔｈｏｆＴ .ｆｅｒｒｏｏｘｉｄａｎｓｈａｖｅｂｅｅｎｃｏｎｄｕｃｔｅｄ…     

Isolation and characterization of acidophilic bacterium from Dongxiangshan Mine in Xinjiang Province, China

One bioleaching bacterium, named as strain DXS, was isolated from acid mine drainages (AMDs) of Dongxiangshan Mine of Hami, Xinjiang Province, China. The strain DXS is gram-negative and rod-shaped with a size of (0.40±0.05) μm×(1.3±0.5) μm. The optimal temperature and pH for growth are 30 ℃ and pH 2.0, respectively. It can grow autotrophically by using ferrous iron, elemental sulfur and NaS2O3 as sole energy sources. In the phylogenetic tree, strain DXS has similarity with Acidithiobacillus ferrooxidans typ...     

Phenotypic and genetic characterization of a novel strain of Acidithiobacillus ferrooxidans （AF2）

A comparative study on the phenotypic and genetic characteristics among Acidithiobacillus ferrooxidans (AF2), a typic strain ATCC23270 and a previously isolated strain AF3 was performed. AF2 can use ferrous ion (Fe²⁺) or elemental sulfur (S⁰) as sole energy source, but oxidizes S⁰ more effectively than Fe²⁺, which is different from ATCC23270 and AF3. The G+C content of AF2 is 51.8% (molar fraction), however, ATCC23270 and AF3 strains have G+C content of 63.7% and 64.8% (molar fraction), respectively. The DNA-DNA hybridization results show that AF2 has 41.53% and 52.38% genome similarity to ATCC 23270 and AF3, respectively, but AF3 has a high genome similarity of 89.86% to ATCC 23270 strain. Rusticyanin (rus) and subunit III of aa₃-type cytochrome oxidase (coxC) genes are not detected in AF2, but Fe²⁺ oxidase (iro) gene can be detected. To understand the genomic organization of iro gene, a cosmid library of AF2 genome was constructed and iro gene-containing clone was screened. The sequencing result shows that although the nucleotide sequence of iro gene in AF2 is completely identical to that of ATCC 23270 strain, its genomic organization is different from that of ATCC 23270. In AF2, iro is located at downstream of purA gene, while it is located at downstream of petC-2 gene in ATCC 23270 strain. These results indicate that AF2 is a novel strain of A. ferrooxidans, and that phenotypic differences among the strains of A. ferrooxidans are closely correlated with their genetic polymorphisms.     

Bioleaching of sphalerite by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans cultured in 9K medium modified with pyrrhotite

Elective culture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans in 9K medium modified with pyrrhotite was studied. Bioleaching of flotation concentrate of sphalerite by the selected bacteria was carried out. The results show that the microorganisms cultured by pyrrhotite are a mixture of Acidithiobacillusferrooxidans and Acidithiobacillus thiooxidans, of which the capability to oxidize ferrous to ferric irons is enhanced by the high mass ratio of Fe to S in pyrrhotite. Three pyrrhotite samples were separated into various parts with corresponding S/Fe ratios by magnetic separation and were used to culture the elective bacteria as the substrate. The association of the cultures could provide a more rapid and complete oxidation of sphalerite than that of bacteria cultivated by conventional methods.     

Bioleaching of soluble phosphorus from rock phosphate containing pyrite with DES-induced Acidithiobacillus ferrooxidans

The effects of Acidithiobacillus ferrooxidans (At. f) mutated with diethyl sulfate (DES) as a mutagen on the bioleaching of soluble phosphorus (P) from rock phosphate (RP) were investigated. The results show that the oxidative activity of At. f is greatly improved by 1.0% (volume fraction) of DES. Correspondingly, the highest leaching rate of soluble P is also obtained to be 14.9% by the At. f mutated, which is 85.8% higher than that of the adapted At. f without mutation. In addition, the SEM images are significantly performed that the corrosion of RP residue surfaces leached by 1.0% DES-induced At.f is much worse than that of leached by the adapted At. f. All the above indicate that the leaching efficiency of soluble P from RP with pyrite can be greatly improved by using DES-induced At. f to a certain extent.     

Acidophilic bacterial community reflecting pollution level of sulphide mine impacted by acid mine drainage

To reveal the impact of mining on bacterial ecology around mining area, bacterial community and geochemical characteristics about Dabaoshan Mine (Guangdong Province, China) were studied. By amplified ribosomal DNA restriction analysis and phylogenetic analysis, it is found that mining pollution greatly impacts the bacterial ecology and makes the habitat type of polluted environments close to acid mine drainage (AMD) ecology. The polluted environment is acidified so greatly that neutrophil and alkaliphilic microbes are massively dead and decomposed. It provided organic matters that can make Acidiphilium sp. rapidly grow and become the most bacterial species in this niche. Furthermore, Acidithiobacillus ferrooxidans and Leptospirillum sp. are also present in this niche. The amount of Leptospirillum sp. is far more than that of Acidithiobacillus ferrooxidans, which indicates that the concentration of toxic ions is very high. The conclusions of biogeochemical analysis and microbiological monitor are identical. Moreover, because the growth of Acidithiobacillus ferrooxidans and Leptospirillum sp. depends on ferrous iron or inorganic redox sulfur compounds which can be supplied by continual AMD, their presence indicates that AMD still flows into the site. And the area is closer to the outfalls of AMD, their biomasses would be more. So the distinction of their biomasses among different areas can help us to find the effluent route of AMD. Foundation item: Project(50621063) supported by the Science Fund for Creative Research Groups of China; Project(2004CB619201) supported by the Major State Basic Research Development Program of China     

Solvent extraction of zinc from zinc sulfate solution

The extraction of zinc from zinc sulfate solution was investigated, using 20% saponified D2EHPA as an extractant and 260^# sulfonate kerosene as a diluent. The solution was stirred for 8 min at phase ratio (V _o/V _a) of 1.0:1.0, initial pH of 2.0 and stirring speed of 200 r/min. The results show that 75% zinc can be extracted from the zinc sulfate solution when the concentration of zinc is 18.7 g/L after being settled for 10 min. 88.60% zinc can be stripped by 196 g/L sulfuric acid, and zinc ion can be separated from ferric ion.     

液—液萃取处理高氯难降解有机废水

农药化工厂生产苯肼、苯唑醇、乙基氯化物过程排放的废水PH＝0．93,CODcr=39406mg/L,BOD5/CODcr=0.02,Cl^-=56563mg/L,是高氯难降解有机废水。采用三辛胺作萃取剂,用液－液取处理,三辛胺与水中Cl^-离子形成萃合物而使Cl^-转移到有机相,再经高效絮凝处理后,CDOcr去除率总计达89．8％,Cl^-去除率总计达83．2％,B／C比从0．02上升到0．34,可生化性大幅度提高。废水再经河水稀释进A／O池生化处理8d后,可达标排放。负载萃取液用5％NaOh水溶液反萃取。由于萃取剂回用降低了处理费用,液－液萃取在废水处理方面有良好的应用前景。     

四株植物根际促生菌对农田土壤N2O排放的影响

农田土壤是温室气体氧化亚氮(N₂O)最重要的人为排放源之一.本文以四株植物根际促生菌:白色芽孢杆菌Bacillus albus Lv5A、枯草芽孢杆菌枯草亚种Bacillus subtilis sp.subtilis NRCB002、施氏假单胞菌Pseudomonas stutzeri NRCB010和暹罗芽孢杆菌Bacillus siamensis NRCB026为研究对象,采用温室盆栽试验、土壤微宇宙试验及田间原位试验等方法,探究接种植物根际促生菌对农田土壤N₂O排放的影响.结果表明,在温室盆栽条件下,接种四株植物根际促生菌的土壤N₂O累积排放量从高到低依次为NRCB002> Lv5A> NRCB026> NRCB010,与未接种的对照相比分别减少了2.3%、33.1%、34.2%和40.0%.选择NRCB010和NRCB026菌株进一步开展土壤微宇宙试验和田间原位试验.与未接种的对照相比,在土壤微宇宙条件下接种NRCB010和NRCB026的土壤N₂O累积排放量分别减少了21%和48%;在田间原位条件下,接种NRCB010和NRCB026的土壤N₂O累积排放量分别减少了44%和73%.总之,接种植物根际促生菌NRCB010和NRCB026能有效减少农田土壤N₂O的排放.研究结果将为减少农田土壤N₂O排放提供重要科学依据,也将为发展具有促生和减排效应的生物肥料提供实际指导.     

柠檬酸废水厌氧颗粒污泥微生物菌群结构解析

为揭示柠檬酸废水生物处理过程中功能菌群作用机制,以柠檬酸工业废水内循环厌氧反应塔(IC)中厌氧颗粒污泥为研究对象,统计颗粒粒径分布,通过环境扫描电子显微镜(ESEM)观察颗粒微观形态结构,利用高通量测序技术分析微生物多样性及菌群特征.结果发现,粒径在1.0~4.0 mm的颗粒所占比例最多,为74.4%.ESEM显示微生物分布以球形细菌为主.高通量测序得到8 397条有效序列,可划分操作分类单元(OTU)873个,Alpha多样性指数显示样品文库覆盖率0.936,Shannon指数为4.376,而ACE指数与Chao1指数分别为3 415.51与2 246.51,反映颗粒污泥中微生物种类与数量均较多.微生物菌群主要包括4大类,分别为可降解有机物的水解发酵菌群Paludibacter、Parabacteroides、Erysipelotrichaceae、Clostridium、Phascolarctobacterium、Aminobacterium、Saccharofermentans与Alkaliflexus(所占比例之和为24.93%);产氢产乙酸菌群Petrimonas与Syntrophomonas(所占比例之和为34.89%);产甲烷菌Methanosaeta(3.44%)及可耐受工业废水毒害的微生物菌群Levilinea、Longilinea与Thermovirga(所占比例之和为14.62%).     

Homology modeling and evolutionary trace analysis of superoxide dismutase from extremophile Acidithiobacillus ferrooxidans

The gene sod in Acidithiobacillus ferrooxidans may play a crucial role in its tolerance to the extremely acidic, toxic and oxidative environment of bioleaching. For insight into the anti-toxic mechanism of the bacteria, a three-dimensional (3D) molecular structure of the protein encoded by this gene was built by homology modeling techniques, refined by molecular dynamics simulations, assessed by PROFILE-3D and PROSTAT programs and its key residues were further detected by evolutionary trace analysis. Through these procedures, some trace residues were identified and spatially clustered. Among them, the residues of Asn38, Gly103 and Glu161 are randomly scattered throughout the mapped structure; interestingly, the other residues are all distinctly clustered in a subgroup near Fe atom. From these results, this gene can be confirmed at 3D level to encode the Fe-depending superoxide dismutase and subsequently play an anti-toxic role. Furthermore, the detected key residues around Fe binding site can be conjectured to be directly responsible for Fe binding and catalytic function. Foundation item: Project(2004CB619201) supported by the National Basic Research Program of China; Project (50321402) supported by the National Natural Science Foundation of China     

Synthesis of calixarenes and their extraction performance for ester catechins

A series of extractants (tert-butylcalix[6]arene, tert-butylcalix[8]arene and octeacetate of tert-butylcalix[8]arene) were synthesized, and their structures were identified by IR and 1H-NMR. The distribution behavior of ester catechins monomer in the aqueous and chloroform two-phase system containing one of calixarene was studied. The influences of different extractants, concentration of tert-butylcalix[8]arene and extraction temperature on the partition coefficients and the separation factors were investigated. The experiment results show that tert-butylcalix[8]arene is the best extractant that forms a more stable supramolecular compound with gallocatechin gallate (GCG) than with epigallocathechin gallate (EGCG) or epicatechin gallate (ECG). When the concentration of p-tert-butylcalix[8]arene is 3.79 mmol/L, the extraction temperature is 4 ℃, the partition coefficients of KGCG, KECG, KEGCG are 0.987, 0.629, 0.449,the separation factors of α1 and α2 are 1.450 and 1.596, respectively. The important factors influencing the extraction properties of calixarene are discovered to be its cavity size and hydrogen bonding.     

铥镱镥富集物萃取分离优化工艺与传统工艺分析比较

针对传统的铥、镱、镥富集物萃取分离工艺存在的问题,以0.5mol/LC272 0.5mol/LP507的新型混合萃取剂代替单一使用P507萃取剂,采用先进行Tm/Lu粗分离,再进行Tm/Yb和Yb/Lu细分离的优化工艺,降低了酸、碱消耗,改善了操作条件.实践证明,该优化工艺可节省酸碱40%以上.     

溶藻菌R1的溶藻特性

以铜绿微囊藻（Microcystis aeruginosa）为受试对象,考察了从太湖土著激荡鱼内脏中筛选的溶藻菌R1菌（Lysinibacillus macroides）的溶藻特性,通过chl-a测定、三维荧光技术,采用高温处置、酸碱处置、透析处置手段,HPLC分离技术,考察了溶藻效果、溶藻产物、溶藻机制及溶藻活性物质。结果表明：菌株R1具有较强的溶藻特性,10 d内chl-a含量从205.11 mg/L降至35.61 mg/L,溶藻率达82.64%;采用荧光强度表征溶藻率,10 d溶藻率达89.80%,与chl-a表征的溶藻率82.64%相近;R1溶藻活性物质是细菌分泌的胞外耐高温类物质,为小分子物质（Mr<500 da）,具有耐酸性碱性;荧光图谱EMMs结合平行因子PARAFAC模型谱分析显示溶藻过程中色氨酸增加,腐殖酸大量减少;主要溶藻产物为长波类类色氨酸类物质,主要为细胞的胞内物质;推测溶藻活性物质疏水性氨基酸（hydrophbic acid）;通过HPLC分离技术,从R1粗提液中分离出1馏分溶藻活性物质,成分还需要进一步的鉴定。     

Electrochemical mechanism of rusticyanin （Rus.） isolated from A. ferrooxidans measured by Rus.-ZnS-QDs/L-Cys/Au electrode

Electrochimcal behaviors of rusticyanin (Rus.) isolated from Acidithiobacillus ferrooxidans were investigated through Rus.-ZnS-QDs/L-Cys/Au electrode.The cyclic voltammetric results indicate that rusticyanin immobilized on the surface of Rus.-ZnS-QDs/L-Cys/Au electrode can undergo a direct quasi-reversible electrochemical reaction.The immobilized rusticyanin is not denatured and still retains its activity in the temperature range of 19-43 °C.The reduction ability of the protein increases and its oxidation a...     

Production and characterization of alkaline extracellular lipase from newly isolated strain Aspergillus awamori HB-03

A strain HB-03 to produce alkaline extracellular lipase was isolated from oil-rich soil samples and identified as Aspergillus awamori.The growth conditions and nutritional factors for lipase production by strain HB-03 were optimized,and the maximum lipase production of (45.9±2.3) U/mL was obtained at 30 °C and pH 7.0 after 36 h using olive oil (1%) and sucrose (0.5%) as carbon sources and combination of peptone (2%),yeast extract (0.5%) and ammonium sulfate (0.1%) as nitrogen sources.The lipase was purified...     

Growth changes and tissues anatomical characteristics of giant reed （Arundo donax L.） in soil contaminated with arsenic, cadmium and lead

A greenhouse experiment was conducted to elucidate the growth changes and tissues anatomical characteristics of giant reed (Arundo donax L.), a perennial rhizomatous grass, which was cultivated for 70 d in soils contaminated with As, Cd and Pb. The results show that giant reed rapidly grows with big biomass of shoots in contaminated soil, possessing strong metal-tolerance with limited metal translocation from roots to shoots. When As, Cd and Pb concentrations in the soil are less than 254, 76.1 and 1 552 mg/kg, respectively, plant height and dried biomass are slightly reduced, the accumulation of As, Cd and Pb in shoots of giant reed is low while metal concentration in roots is high, and the anatomical characteristics of stem tissues are thick and homogeneous according to SEM images. However, plant height and dried biomass are significantly reduced and metal concentration in plant shoots and roots are significantly increased (P<0.05), the stems images become heterogeneous and the secretion in vascular bundles increases significantly when As, Cd and Pb concentrations in the soil exceed 334, 101 and 2 052 mg/kg, respectively. The giant reed is a promising, naturally occurring plant with strong metal-tolerance, which can be cultivated in soils contaminated with multiple metals for ecoremediation purposes.     

Semiviscosity flow equation with variable parameters under superplastic tension conditions

Ａｓｅａｒｌｙａｓｉｎ1964,Ｂａｃｋｏｆｅｎｅｔａｌ.ｂｅｌｉｅｖｅｄｔｈａｔｕｎｄｅｒｓｕｐｅｒｐｌａｓｔｉｃｃｏｎｄｉｔｉｏｎｓｈａｒｄｌｙａｎｙｓｔｒａｉｎｈａｒｄｅｎｉｎｇｔａｋｅｓｐｌａｃｅｄｕｒｉｎｇｔｈｅｄｅｆｏｒｍａｔｉｏｎｏｆｍａｔｅｒｉａｌｂｕｔｔｈｅｒｅｉｓａｓｔｒｏｎｇｓｔｒａｉｎｒａｔｅｈａｒｄｅｎｉｎｇ[1].Ａｎｄｔｈｅｙａｌｓｏｅｓｔａｂｌｉｓｈｅｄｔｈｅｓｅｍｉｖｉｓｃｏｓｉｔｙｅｑｕａｔｉｏｎσ=ｋεｍ,(1)ｗｈｉｃｈｉｎｄｉｃａｔｅｓｔｈｅｒｅｌａｔｉｏｎｂｅｔｗｅ…