1株氧化亚铁硫杆菌的分子鉴定及生物学特性研究

从四川省攀枝花露天铁矿及煤矿的坑水和圬泥中分离出1株氧化亚铁硫杆菌pzh-1,用扫描电镜观察该菌的形态,对其生理生化特性、生长条件等进行了研究,且对该菌的16SrDNA序列进行分析并建立系统发育树。结果表明,该菌的最佳生长条件为:初始pH值为2~2.5,温度为30~35℃,初始Fe2+浓度为9 g/L,接种量为10%;该菌短期保藏采用单蒸水悬浮细菌(pH6.8),在4℃保藏效果最佳。     

Chalcocite Oxidation and Coupled Carbon Dioxide Fixation by Thiobacillus ferrooxidans

The reaction of cell suspensions of Thiobacillus ferrooxidans with pulverized chalcocite (Cu(2)S) in a Warburg manometric apparatus resulted in oxygen uptake accompanied by increased solubilization of copper and fixation of carbon dioxide. Since the only detectable oxidized products were cupric ions and the more oxidized form of the sulfide mineral, that is, digenite or covellite, the apparent source of energy for the carbon dioxide fixation was provided by the oxidation of the cuprous copper of the chalcocite.     

The Exclusion of D2O from the Hydration Sphere of FeSO4{middle dot} 7H2O Oxidized by Thiobacillus ferrooxidans

Infrared spectra demonstrate that neither FeSO(4) . 7H(2)O nor its bacterial or abiotic hydrated oxidation products incorporate deuterium in acid D(2)O solutions. Deuterium exchange occurred as bridging OD when bacterially oxidized iron was precipitated from D(2)O solutions as ferric hydroxysulfates. The exclusion of deuterium depended upon the stabilization of aquated Fe(II) and Fe(III) complexes by sulfate ions in outer-sphere coordination and is consistent with the requirement and postulated role of sulfate in iron oxidation by Thiobacillus ferrooxidans.     

氨基酸营养对At.f菌生长迟缓期的影响

[目的]研究氨基酸营养对At.f菌生长迟缓期的影响。[方法]将At.f在分别加入20种氨基酸的培养基中培养,利用重铬酸钾滴定法测定各时段Fe2＋利用情况,并检测添加氨基酸后培养基pH的变化。[结果]非极性氨基酸对缩短At.f菌的迟缓期的效果较明显;苯丙氨酸、酪氨酸、脯氨酸、色氨酸四种成环氨基酸有较好的效果;丝氨酸、谷氨酰胺、组氨酸有明显的抑制作用。[结论]非极性氨基酸能有效缩短At.f菌生长迟缓期,部分极性氨基酸则起到相反效果。     

生物淋滤法对污泥中Zn Cu的去除效果及污泥养分损失研究

采用序批式摇床培养，在污泥中分别接种10％的氧化亚铁硫杆菌菌液与氧化硫硫杆菌菌液，研究了不同菌种对生物淋滤法去除城市污泥中重金属Zn和Cu效果的影响。结果表明，氧化亚铁硫杆菌能够较快速启动生物淋滤，使污泥系统中的Zn在第2d就有了97．8％的去除，并保持到结束；Cu在第4d有了37％的去除并持续升高。而氧化硫硫杆菌则在第6d才对Zn和Cu有了较好的去除。2种金属的溶出与pH值有一定的相关性，zn在pH值3．0～4，0时就有很高的去除率，而Cu在pH〈3．0时才有较好的去除。在去除重金属的同时，污泥中营养成分（TN、TP、TK、有机质）的损失也较高，特别是TP的损失量最高可达到70％。以氧化亚铁硫杆菌为优势的生物淋滤系统中污泥的营养损失大于氧化硫硫杆菌为优势的系统。     

一株嗜酸性氧化亚铁硫杆菌的分离及其氧化活性的研究

本研究从铜陵新桥矿区的高硫矿堆废水中分离一株嗜酸菌S t1,经生理生化特征及16S rDNA分子鉴定,确定其为嗜酸性氧化亚铁硫杆菌。该菌株分别在含有FeSO4·7H2O、S0、黄铁矿石颗粒（FeS2）的9K无机盐液体培养基中获得生长所需要的能量。结果嗜酸菌S t1对Fe2＋氧化速率最快,培养到36h时溶液中44.1g·L-1 FeSO4·7H2O有95%被氧化;S0为能量底物的培养体系中,培养到26d时培养液中SO42-浓度达到2.2412 mg· mL-1,pH值降至1.18;黄铁矿石颗粒（FeS2）为能量底物的培养体系中,SO42-平均生成速率为1.3602 mmol·L-1·d-1,黄铁矿石颗粒氧化速率达到0.068mmol·d-1·g-1。     

氧化亚铁硫杆菌的磁性及铁源种类对磁小体合成的影响

氧化亚铁硫杆菌,通过氧化二价铁或还原态无机硫化物获得能量,在细胞内能合成磁性纳米颗粒。通过扫描电镜和透射电镜对氧化亚铁硫杆菌菌体进行分析。探讨了该菌的趋磁性以及不同铁源对菌体生长和磁小体合成的影响。结果表明:生长于9K培养基的细菌能够合成磁小体,单个细胞的磁小体数目大概为2个;干燥菌体和湿菌体都能被磁铁吸附;当有外加磁场时,细菌在半固体平板和光学显微镜下均可见趋磁性;氧化亚铁硫杆菌生长和磁小体合成的最佳铁源均为硫酸亚铁。     

不同氨基酸对At.f菌生长情况的影响

通过在不同pH条件下培养At.f菌,并监测其生长情况,以确定At.f菌生长的最适pH,再向所确定的最适pH的9K培养基中添加不同氨基酸,研究不同氨基酸对At.f菌生长情况的影响。结果表明：pH为2.0的培养基中菌种的生长情况最好;另外丙氨酸、缬氨酸、亮氨酸、异亮氨酸、甲硫氨酸、苯丙氨酸、色氨酸、脯氨酸、酪氨酸、甘氨酸、半胱氨酸对Fe^2＋的利用率较高,而丝氨酸、天冬酰胺、谷氨酰胺、组氨酸作用结果则相反。从而得出结论：At.f菌生长的最适pH为2.0;非极性氨基酸、成环氨基酸对At.f菌生长有促进作用,丝氨酸、天冬酰胺、谷氨酰胺、组氨酸对At.f菌生长有抑制作用。     

High-selectivity, high-flux silica membranes for gas separation

Process improvements in silica membrane fabrication, especially the use of clean-room techniques, resulted in silica membranes without detectable mesoscopic defects, resulting in significantly improved transport properties. Supported membranes calcined at 400 degreesC were 30 nanometers in thickness, showed a H2 permeance at 200 degreesC of 2 x 10(-6) moles per square meter per second per Pascal (mol m-2 s-1 Pa-1), and had a CH4 permeance more than 500 times smaller. Molecules larger than CH4 were completely blocked. Silica membranes calcined at 600 degreesC showed no detectable CH4 flux, with a H2 permeance of 5 x 10(-7) (mol m-2 s-1 Pa-1) at 200 degreesC. These results signify an important step toward the industrial application of these membranes such as purification of H2 and natural gas as well as the selective removal of CO2.     

自然铜的生物转化研究

利用Acidithiobacillus ferrooxidans ATCC23270(A.ferrooxidans ATCC23270)对自然铜进行生物转化,考察矿浆浓度,微生物接种量,系统初始pH,浸出时间以及温度对自然铜转化的影响。利用单因素法对A.ferrooxidans转化自然铜进行条件优化。结果表明,自然铜最佳浸出工艺为矿浆浓度0.5%、系统初始pH值1.75、接种量10%、浸出时间15 d以及环境温度35℃,浸出率可达65.32%。初步获得了A.ferrooxidans转化自然铜的条件,为中药的炮制提供新思路。     

硫细菌对黄绵土养分活化作用的研究

分析了氧化硫硫杆菌的产酸力及其对黄绵土中Ｐ、Ｚｎ、Ｍｎ养分的活化作用结果表明,氧化硫硫杆菌可使环境ＰＨ值降低１－３个单位;接种于黄绵土垢可显著增加土壤中Ｃａ２－Ｐ、Ｃａ８－Ｐ、Ａｌ－Ｐ的含量,土壤中有效Ｚｎ、Ｍｎ量也明显提高。ｔ检验均达显著或极显著水平;田间试验表现显著的增产效果。     

萱草花色素的超声波辅助提取及其稳定性研究

以‘摩盒’萱草花为试验材料,对萱草花色素的超声波辅助提取工艺进行了优化,同时研究了光照、温度、pH值、氧化剂、还原剂对萱草花色素提取液稳定性的影响。结果表明,用纯乙醇做提取液,料液比为1∶10、超声时间30 min时,提取效果最好;萱草花色素对光照比较敏感,在暗处稳定性最高,在自然光下次之,直射光下最低;萱草花色素在35℃以下热稳定性较好,超过35℃时热稳定性大大降低;花色苷类在强酸时稳定,弱酸性和中性条件下稳定性降低;类胡萝卜素类在酸性条件下不稳定,在中性和弱碱性条件下保持稳定;花色苷类和类胡萝卜素类抗氧化能力较好,抗还原能力差。     

2种蓝藻的生长对不同环境pH的响应

利用静态实验法研究了满江红鱼腥藻和固氮鱼腥藻在不同pH环境中的生长与环境的相互关系。实验结果表明,在pH5～9的环境中,2种藻都可以正常生长,且生长的过程中还改变了生长环境的pH值,酸性环境pH值都发生上升,碱性环境的pH改变不大。在pH3和11的环境中,2种藻的生长都受到抑制。     

二甲基硫醚氧化菌的分离鉴定及其对猪粪堆肥的影响

从污水处理厂活性污泥中分离得到一株二甲基硫醚(DMS)氧化菌AM2,经16S rDNA检测鉴定其为那不勒斯硫杆菌(Thiobcillus neapolitanus)。AM2的最适生长温度为30℃最适pH为7.0。以猪粪和秸秆粉为原料进行肥料堆肥试验,通过检验菌株AM2对堆肥过程中DMS排放量、堆肥温度、可培养微生物和酶活性的影响,来探究菌株AM2对堆肥的影响。结果表明:接入菌株AM2的实验组DMS释放量显著(P0.05)少于对照组,在30 d的实验中有20 d减少60%以上;显著提高了(P0.05)可培养微生物数量,同时将物料温度高于50℃的天数延长至13 d;实验各组的脲酶、脱氢酶、过氧化氢酶、蛋白酶和纤维素酶酶活都显著高于对照组。综合判断,菌株AM2能够有效降低堆肥过程中DMS的排放量并促进肥料腐熟。     

铜绿假单胞菌Z1产鼠李糖脂理化性质的研究

[目的]为分析前期研究获得的产糖脂铜绿假单胞菌株及其发酵产物应用于石油、食品、环境和农业等领域的潜力,从而对该糖脂粗提物的理化性质进行研究。[方法]检测铜绿假单胞菌Z1发酵产生鼠李糖脂粗提物的CMC,并研究其在不同温度、盐度、酸碱度下表面活性的稳定性,同时与化学表面活性剂SDS进行比较。[结果]Z1产鼠李糖脂在-20℃常压和121℃的高温高压下表面张力均保持在40 mN/m以下,在NaCl浓度达30%情况下,表面张力也保持在37 mN/m以下,但在pH<4及pH>10的情况下,其表面张力均大于40 mN/m,分析可得其对温度、盐度表现极强的耐受性,但对酸碱度的耐受性较弱。[结论]该研究表明,鼠李糖脂表现具有极高的温度和盐度耐受性,且研究中的铜绿假单胞菌菌株或其发酵获得的糖脂粗提物具有推广应用于石油等领域的潜力。研究不足之处在于该糖脂在酸碱度的耐受性方面较弱,需进行改进。     

模拟酸雨对聚氯乙烯农膜中增塑剂析出的影响

选取某种聚氯乙烯(PVC)农膜进行测试,分析其中所含增塑剂种类以及在模拟酸雨浸泡下增塑剂的析出特性。结果表明,该农膜中添加的增塑剂为邻苯二甲酸-2-乙基己基酯(DEHP),在模拟酸雨浸泡下PVC膜中析出的物质主要为DEHP。当溶液pH值为6.5和5.6弱酸性时,PVC膜析出的DEHP量相对最大,在30d内分别减少了2.66%和2.38%。而当pH值为7.0和2.5时,PVC膜析出的DEHP量中等(30d分别为1.46%和1.52%),当溶液pH值为3.0和4.0时,PVC膜中DEHP的含量水平在30d内只降低了1.33%和1.22%。研究发现,在pH值为5.6和6.5弱酸性酸雨模拟液中,DEHP易于在溶液中分散和降解,并可使PVC膜表面产生一定程度的龟裂,利于PVC膜中DEHP析出。     

The postspinel phase boundary in Mg2SiO4 determined by in situ X-ray diffraction

The phase boundary between spinel (gamma phase) and MgSiO3 perovskite + MgO periclase in Mg2SiO4 was determined by in situ x-ray measurements by a combination of the synchrotron radiation source (SPring-8) and a large multianvil high-pressure apparatus. The boundary was determined at temperatures between 1400 degrees to 1800 degreesC, demonstrating that the postspinel phase boundary has a negative Clapeyron slope as estimated by quench experiments and thermodynamic analyses. The boundary was located at 21.1 (+/-0.2) gigapascals, at 1600 degreesC, which is approximately 2 gigapascals lower than earlier estimates based on other high-pressure studies.     

模拟酸雨和铝添加对茶树生长及生理生化特性的影响

以茶树(Camellia sinensis)种子实生苗为材料,研究了模拟酸雨和铝添加对茶树生物量、抗氧化酶及一些抗性指标的影响.结果表明,适量的铝和适度的酸雨有利于茶树生物量的积累,较高的铝和较高酸度酸雨不利于茶树生物量的积累.随着铝处理浓度的增加,茶树叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)先增加后下降.随着酸雨强度的增加,SOD、POD、CAT和APX总体上增加,在较低浓度铝处理下,酸雨加剧SOD、POD、CAT和APX的增加,存较高铝浓度(30 mg/L)处理下,酸雨加剧SOD、POD、CAT和APX的下降.10 mg/L铝浓度处理茶树叶片超氧阴离子产生速率(O2-)和丙二醛(MDA)含量与无铝处理的相比没有明显差异,随着铝处理浓度的增加其O2-产生速率和MDA含量增加.酸雨强度对茶树叶片O2-产生速率和MDA含量没有明显影响.酸雨加剧铝引起茶树叶片O2-产生速率和MDA积累的增加.随着铝处理浓度的增加,茶树叶片脯氨酸含量增加.而酸雨单独作用对脯氨酸含量没有明显影响,但酸雨加剧铝对茶树叶片脯氨酸积累的增加.随着铝处理浓度的增加,茶树叶片可溶性糖含量先增加后下降.pH 3.0的酸雨明显提高茶树叶片可溶性糖含量.结果表明,茶树可通过提高抗氧化酶活性和一些渗透调节物质(脯氨酸和可溶性糖)增强对酸雨和低浓度铝的适应性和耐受能力.高浓度的铝(30 mg/L)损伤茶树抗氧化系统,减少一些抗性物质的合成,影响其生长,而酸雨加剧高铝对茶树的伤害.     

The effect of alumina on the electrical conductivity of silicate perovskite

Measurements of the electrical conductivity of silicate perovskite at 25 gigapascals and 1400 degrees to 1600 degreesC show that the conductivity of (Mg,Fe)SiO3 perovskite containing 2.89 weight percent Al2O3 is about 3.5 times greater than that of aluminum-free (Mg0.915Fe0.085)SiO3 perovskite. The conduction mechanism in perovskite between 1400 degrees and 1600 degreesC is most likely by polarons, because Mossbauer studies show that the aluminum-bearing perovskite has about 3.5 times the amount of Fe3+ as the aluminum-free sample. A conductivity-depth profile from 660 to 2900 kilometers based on aluminum-bearing perovskite is consistent with geophysical models.     

Soil nitrite as a source of atmospheric HONO and OH radicals

Hydroxyl radicals (OH) are a key species in atmospheric photochemistry. In the lower atmosphere, up to ~30% of the primary OH radical production is attributed to the photolysis of nitrous acid (HONO), and field observations suggest a large missing source of HONO. We show that soil nitrite can release HONO and explain the reported strength and diurnal variation of the missing source. Fertilized soils with low pH appear to be particularly strong sources of HONO and OH. Thus, agricultural activities and land-use changes may strongly influence the oxidizing capacity of the atmosphere. Because of the widespread occurrence of nitrite-producing microbes, the release of HONO from soil may also be important in natural environments, including forests and boreal regions.