In situ Restoration of the Surface Defects on Cement-based Materials by Bacteria Mineralization with Spraying Method

Defects of cement-based materials can be restored by microbial carbonate precipitation, but in order to accelerate the completion of the mineralization process, previous studies all adopt the approach of immersion in bacterial liquid, which can not be applied for in situ repair. We investigated micro-environment, basophil-domestication of microorganism and effective absorption of micro-organisms by cement-based materials, and adopted spray technology to conduct in situ repairs on the defects on the surface of cement-based materials and enhance the repair process operability. Through microbial carbonate precipitation in the defects by spraying bacteria liquid, 100 μm thickness of calcium carbonate film can be deposited on sample surface and in defects holes＇ microenvironment within 3 to 5 days. The capillary water absorption coefficient of specimen surface is 77% lower than the value before repair. The repairing effect is remarkable which makes it possible to conduct on-site repairs.

Effect of Mineral Dusts on the Growth of Silicate Bacteria S35

In order to compare the chemical compositions and physical properities of dusts on silicate bacteria S35, the chemical compositions of six kinds of mineral dusts have been analyzed and the changes of pH value, glucose （GLU）, electrolyte and Mn, Si, Fe before and after the dusts reacted with silicate bacteria S35 have been measured. The SEM analysis has been used to study the bacterial form and interface action status in the course of reaction between dusts and bacteria. The results show that these mineral dusts have different effects on experiment bacteria. Therefore, it is concluded that the effect of mineral dusts on silicate bacteria has correlation with the chemical compositions and physical properities of dusts.

Modification of total and phosphorus mineralizing bacterial communities associated with Zea mays L.through plant development and fertilization regimes

Harnessing the rhizospheric microbiome,including phosphorus mineralizing bacteria(PMB),is a promising technique for maintaining sustainability and productivity in intensive agricultural systems.However,it is unclear as to which beneficial taxonomic group populations in the rhizosphere are potentially associated with the changes in soil microbiomes shifted by fertilization regimes.Herein,we analyzed the diversity and community structure of total bacteria and PMB in the rhizosphere of maize(Zea mays L.)grown in soils under 25 years of four fertilization regimes(compost,biocompost,chemical,or nonfertilized)via selective culture and Illumina sequencing of the 16S rRNA genes.Plant development explained more variations(29 and 13%,respectively)in the composition of total bacteria and PMB in the rhizosphere of maize than the different fertilization regimes.Among those genera enriched in the rhizosphere of maize,the relative abundances of Oceanobacillus,Bacillus,Achromobacter,Ensifer,Paracoccus,Ramlibacter,and Luteimonas were positively correlated with those in the bulk soil.The relative abundance of Paracoccus was significantly higher in soils fertilized by compost or biocompost than the other soils.Similar results were also observed for PMB affiliated with Ensifer,Bacillus,and Streptomyces.Although plant development was the major factor in shaping the rhizospheric microbiome of maize,fertilization regimes might have modified beneficial rhizospheric microbial taxa such as Bacillus and Ensifer.

Selective adsorption of bacteria on sulfide minerals surface

The adsorption of bacteria on sulfide minerals surface was studied,and the selective adsorption mechanism of cells on the sulfide minerals was investigated by means of FTIR,UVS and XPS.The results show that the three strains of bacteria adsorbed more preferentially on pyrite than on other two sulfide minerals surface at neutral and alkaline pH conditions.FTIR and UVS of three strains of bacteria indicate that there are more functional groups on their surface,such as O-H,C=O,N-H,C-O,and the content of saccharide is more than that of protein.The state of every element on sulfide minerals surface was analyzed by XPS.The empty orbital number of electronic shell of metal ions on minerals surface is important in selective adsorption process,and some stable constants of metal coordinates can be used to explain the contribution of some groups in saccharide of cell wall to the selective adsorption.

Marmatite bioleaching with moderately thermoacidophilic bacterial strain and mineral analyses of solid residues

The bioleaching of a marmatite flotation concentrate with a moderately thermoacidophilic iron-oxidizing bacterial strain (MLY) is influenced significantly by temperature, pH, particle size, pulp density of ores and bacterial strains. Under such leaching conditions as the initial pH value of 1.5, temperature of 50℃, pulp density of 5%, particle size less than 35.5μm (over 90%) and inoculating the adapted strains of MLY, the leached Zn is over 95% after 10d of bioleaching. SEM observations show the cell attachment and the surface features of solid residues under different leaching conditions. XRD and EDX analyses show that a mass of elemental sulfur form during the bioleaching process. The technological feasibility of a microbiological process using MLY for extracting zinc from the marmatite concentrate is demonstrated.

Preliminary study on treatment of waste organic matter from livestock by bacteria-mineral technology

The present study dealt with relationships between the degradation and humification process that the organic matter underwent during bacteria-mineral technology. An inverse correlation was found between the protein, lipid, and some of the humification indices considered, suggesting that the humification theory is actually humic substances produced from simple-structured natural organic substrates. Weight-average molecular weight （Mw）, number-average molecular weight （Mn）, and the ratio Mw/Mn of dissolved organic matters at different stages of the process were measured by gel permeation chromatography. The results showed that Mn and Mw increased with reaction time from 352 to 17,191, and from 78,707 to 104,564, respectively. The ratio of Mn/Mw decreased from 223.3 to 6.1. This reflected the growth of the polymerization degree of dissolvable organic matters in the process; furthermore, it indicated the formation of complex molecules （humic substances） from more simple molecules. Bacteria-mineral water （BMW） （the effluent of the process） treatments can exert hormone-like activity for enhanced seed germination of wheat and rice and greatly improved chlorophyll synthesis in wheat and rice leaves, Major polyamines （plant regulators） putrescine, spermidine, and spermine, were found in BMW by a high performance liquid chromatography （HPLC） method, which may explain the hormone-like activity of BMW.

Efficiency of potassium-solubilizing Paenibacillus mucilaginosus for the growth of apple seedling

Chemical potassium(K)fertilizer is commonly used in apple(Malus domestica L.Borkh)production but K is easily fixed by soil,resulting in reduced K ferilizer utilization and wasted resources.K-solubilizing bacteria(KSB)can cost-effectively increase the soluble K content in rhizosphere soil.Therefore,the objectives were to select high-efficiency KSB from apple orchards under various soil management models and evaluate their effects on apple seedling growth.Maize(Zea maysL.)straw mulching(MSM)increased the total carbon(TC),total nitrogen(TN)and available potassium(AK)in the rhizosphere and improved fruit quality.The number of KSB in the rhizosphere soil of MSM was 9.5×10×CFU g1 soil,which was considerably higher than that in the other mulching models.Fourteen KSB strains were isolated with relative K solubilizing ability ranging from 17 to 30%,and five strains increased the dry weight per apple seedling.The most eficient strain was identified as Paenibacillus mucilaginosus through morphological observation and sequence analysis of 16S rDNA,named JGK.After inoculation,the colonization of JGK in soil decreased from 4.0 to 1.5×10×CFU g^-1 soil within 28 d.The growth of the apple seedlings and the K accumulation in apple plants were promoted by irigation with 50 mL JGK bacterial solution(1×10^9 CFU mL^-1),but there was no significant increase in the AK content of rhizosphere soil.High-performance liquid phase analysis(HPLC)data showed that the JGK metabolites contained phytohormones and organic acids.Hence,the JGK strain promoted the growth of two-month-old apple seedlings by stimulating function of the produced phytohormones and enhanced K solubility by acidification for apple seedling uptake.This study enriches the understanding of KSB and provides an effective means to increase the K utilization efficiency of apple production.

Leptosririllumferrooxidans-sulfide mineral interactions with reference to bioflotation nad bioflocculation

铁的离子的粘附黄铁矿和黄铜矿矿物质上的成年 Leptospirillum ferrooxidans 房间通过吸附，希腊语的第六个字母潜力和弥漫的反射英尺红外被调查大小。当絮凝行为被 Turbiscan 大小检验时，矿物质 floatability 上的细菌的种类的影响被 Hallimond 筹款测试决定。矿物质等电位的点(pH 6.5 ? 7.5 ) 在和细菌的房间的相互作用向房间转移了等电位的点以后(pH 3.3 ) ，在矿物质上显示房间吸附的化学性质出现。与细菌的房间对待的矿物质的英尺红外系列显示出所有房间的存在功能的组意味着房间吸附。黄铜矿上的细菌的房间吸附与黄铁矿相比是更高的，它同意了房间与黄铁矿比较的黄铜矿筹款和显著絮凝行为上的更大的萧条效果。

嗜酸铁氧化细菌生物矿化研究进展及其应用

重点介绍嗜酸铁氧化细菌的胞内胞外矿化研究进展,概述嗜酸铁氧化细菌胞内矿化产物性质和影响矿化产物合成的因素,整理现阶段磁性纳米颗粒的合成机制;对嗜酸铁氧化细菌胞外矿化产物的合成原理和影响因素进行汇总;最后总结嗜酸铁氧化细菌矿化产物的应用前景,并指出当下磁性纳米颗粒研究的不足。针对研究现状提出未来依赖分子生物学解析胞内矿化机制并拓展其应用范围的新思路,该研究有望为进一步研究嗜酸铁氧化细菌胞内胞外矿化及其应用提供理论指导。

鱼菜共生系统中乳酸菌的筛选及其发酵矿化应用

针对鱼菜共生系统固体废弃物资源化利用效率低的问题,该研究旨在筛选出抗逆性好、矿化功能强的鱼源性乳酸菌,加强鱼粪残饵的发酵矿化性能。试验从鱼菜共生系统中的生物滤料和鱼体中分离乳酸菌,并通过抗逆性及发酵矿化性能检测,筛选出2株具有应用潜力的鱼粪残饵矿化菌株,经鉴定分别为乳酸乳球菌(Lactococcus lactis)L1和糊精乳杆菌(Lactobacillus dextrinicus)L2。耐温性、耐酸碱性和耐盐性检测结果显示,L1表现出较好的抗逆性。在50℃时,L1存活率为96.60%,显著高于L2的存活率80.35%(P<0.05);在pH值分别为5.0和9.0时,L1的存活率分别为65.43%和71.25%,高于L2的存活率31.10%和52.22%(P<0.05);当盐浓度为60 g/L时,L1的存活率为37.33%,而L2无法存活。通过比较对照组(CK组,未添加乳酸菌)和乳酸乳球菌组(L组,添加乳酸乳球菌)发酵矿化过程中发酵液水质和矿物元素含量,结果显示L组的有机物降解及矿化效果更好,除硫(S)元素以外,钾(K)、钙(Ca)、镁(Mg)、铁(Fe)、锰(Mn)和锌(Zn)元素的矿化率均在第3天达到最高(27.59%~94.67%)。综上所述,乳酸乳球菌(Lactococcus lactis)具有较强的抗逆性和显著的发酵矿化效果,且其最佳发酵矿化周期为3 d。该研究可为提高鱼菜共生系统固体废弃物资源化利用效率提供技术支持。

微生物矿化对黏土渗透性影响的试验研究

为探究矿化对黏土渗透性的影响,采用球形赖氨酸芽孢杆菌属kp-22菌诱导矿化处理黏土,测定了碳酸盐生成率,研究了矿化处理后黏土的渗透性,系统分析了渗透系数随菌液OD600值、胶结液浓度和土中镉含量变化的规律,探讨了各因素对渗透系数的影响规律及机理,建立了考虑菌液OD600值和胶结液浓度影响的矿化后黏土渗透系数的经验公式。结果表明:矿化后的土样中生成了碳酸盐颗粒,填充了部分土体孔隙,渗透系数最多可降低约一个数量级;随着菌液OD600值的增大,矿化后黏土的碳酸盐生成率先升高后逐渐稳定,而土样的渗透系数先减小后趋于平稳,当菌液OD600值大于0.9时,碳酸盐生成率和渗透系数都变化很小;随着胶结液浓度增大,碳酸盐生成率先升高后下降,而渗透系数先减小后增大,当胶结液浓度为0.8 mol/L时,黏土的渗透系数最小;随着土中镉含量的增大,矿化反应受到抑制,渗透系数逐渐增大;矿化后黏土的渗透系数与碳酸盐生成率负相关,两者满足线性关系;所建立的矿化后黏土渗透系数经验公式计算值与试验结果吻合较好。

微氧生物亚铁氧化及其重金属固定效应研究进展

铁的生物地球化学循环对于多种环境过程至关重要,如碳封存、温室气体排放以及营养元素和有毒金属的迁移和转化。近年来,随着分离培养方式及分子生物学方法的发展,作为铁循环的重要组成部分的微氧生物铁氧化的研究取得了显著的进展。微氧型亚铁氧化菌广泛分布于近中性环境中,其分离栖息地从地下水、湿地、溪流延展至深海环境。微氧生物亚铁氧化成矿过程主要发生在细胞表面,生成比表面积较大的无定型铁氧化物。大部分微氧型亚铁氧化菌通过形成鞘状或螺旋柄状结构的胞外多聚物吸附生成的铁氧化物,防止自身被铁氧化物包埋,导致无法正常代谢而死亡。亚铁氧化成矿过程可吸附和共沉淀重金属元素,降低重金属的移动性和生物可利用性,从而缓解重金属的污染,为治理环境污染提供新的思路。文章主要总结了近年来国内外对嗜中性微氧型亚铁氧化菌的研究进展,包括其代谢特征、种类及分布、以及亚铁氧化菌的成矿机制和成矿过程对重金属迁移转化的影响。最后对如何快速有效地分离微氧型亚铁氧化菌、明确成矿过程中的特殊结构的形成机制等问题进行了讨论和展望。

The effect of extracellular polymeric substances (EPS) of iron-oxidizing bacteria (Ochrobactrum EEELCW01) on mineral transformation and arsenic (As) fate

Extracellular polymeric substances(EPS)are an importantmedium for communication and material exchange between iron-oxidizing bacteria and the external environment and could induce the iron(oxyhydr)oxides production which reduced arsenic(As)availability.The main component of EPS secreted by iron-oxidizing bacteria(Ochrobactrum EEELCW01)was composed of polysaccharides(150.76-165.33 mg/g DW)followed by considerably smaller amounts of proteins(12.98–16.12 mg/g DW).Low concentrations of As(100 or 500μmol/L)promoted the amount of EPS secretion.FTIR results showed that EPS was composed of polysaccharides,proteins,and a miniscule amount of nucleic acids.The functional groups including-COOH,-OH,-NH,-C=O,and-C-O played an important role in the adsorption of As.XPS results showed that As was bound to EPS in the form of As3+.With increasing As concentration,the proportion of As3+adsorbed on EPS increased.Ferrihydrite with a weak crystalline state was only produced in the system at 6 hr during the mineralization process of Ochrobactrum sp.At day 8,the minerals were composed of goethite,galena,and siderite.With the increasing mineralization time,the main mineral phases were transformed from weakly crystalline hydrous iron ore into higher crystallinity siderite(FeCO_(3))or goethite(α-FeOOH),and the specific surface area and active sites of minerals were reduced.It can be seen from the distribution of As elements that As is preferentially adsorbed on the edges of iron minerals.This study is potential to understand the biomineralizationmechanism of iron-oxidizing bacteria and As remediation in the environment.

The Conditions of Releasing Potassium by a Silicate- dissolving Bacterial Strain NBT

The potassium-releasing characteristics of a bacterium from different minerals were studied through pure culture and soil column experiments. The results showed that the strain NBT of tested strains had the highest potassium-releasing capacity. It released 35.2 mg/L after 7days of pure culture incubation at 28@, 31.8% - 1203.7% more than other tested strains. Potassium released from the minerals was obviously affected by pH, aerobic condition, soil and mineral properties. The strain NBT had a much higher potential to release potassium in the pH 6.5-8.0 than other pHs. Living cell inoculation resulted in an increase of 84.8% -127.9% compared with that of the dead cell inoculation. More aerobic condition produced more K than a less aerobic one. The potassium-releasing order was as follows: illite>feldspar>muscovite. Soil column experiment showed that the bacterial number increased from (2.6 - 3.0) × 106/g to (6.8 - 7.4) × 107/g. Soil available potassium content increased by 31.2 - 33.6mg/kg in yellow-brown soil and 21.7mg/kg in paddy soil, when inoculated with the strain NBT, 290.6% and 185.5% increment of the dead cell inoculation soils respectively.

Dolomite apatite separation by amphoteric collector in presence of bacteria

Bioflotation represents one of the growing trends to enhance the selectivity of conventional flotation processes. It utilizes the micro-organisms to replace or to interact with the chemical reagents to increase the gap between surface properties of similar minerals and to enhance the separation selectivity. In this work, dolomite-phosphate separation was investigated using amphoteric collector （dodecyl-N-carboxyethyl-N-hyroxyethyl-imidazoline） in presence of bacteria. Two types of bacteria, Corynebacterium- diphtheriae-intermedius （CDI）, and Pseudomonas aeruginosa （PA）, were used. The collector-bacteria interaction was characterized by Fourier transform infra-red （FTIR）, frothing height and Zeta potential. The results show that the collector-bacteria interaction improves the flotation selectivity. Although, the PA positively affects the separation results, the CDI cannot lower the MgO to less than 1%. A phosphate content of 0.7% MgO and 31.77% P205 with a recovery of 68% at pH 11, 3.0 kg/t amphoteric collector, 4× 10^7 cells of PA is obtained.

Variation of Bacteria Biomass and its Possible Controlling Factors in the East China Sea

Two surveys were performed for determining bacteria biomass (BB), temperature, salinity, chlorophyll a (chl-a) and nutrient concentrations at 11 stations with three sampling depths in the high-incidence regions of red tide in the East China Sea (ECS) in the spring of 2006. Temperature and salinity increased from nearshore to offshore region and from high latitude to low latitude in the two cruises of 2006. BB were between 0.3 5.2 mgC m-3 (about 2.1 mgC m-3 on average) and 0.2 6.0 mgC m-3 (about 2.7 mgC m-3 on average) respectively in the two cruises. BB in the surface layer decreased from the Changjiang River estuary to high sea and from low latitude to high latitude. The results showed that bacterial growth was regulated by temperature, primary production and inorganic nutrient concentrations depending on different hydrographic conditions. In the surface and middle layers where the primary production can supply enough organic substrate, temperature was the main factor to control bacteria biomass. BB showed a good correlation between the surface and middle layers in both cruises. The distribution of nutrients during both cruises showed a similar decreasing trend from nearshore region and high latitude to offshore region and low latitude. High BB values were mainly recorded from samples in the middle layer where chl-a concentrations were also high, indicating primary production being strongly correlated with temperature over the ECS shelf. In the offshore area, phosphate and silicate became limiting factors for phytoplankton growth with indirect influence on BB. Bacteria played an important role in nitrogen regeneration process turning organic nitrogen to inorganic forms such as NH4+. The increasing ratio of NH4+/DIN could be a proof of that.

蒙脱石-碳酸盐矿化菌对Sr^(2+)的联合去除作用研究

通过构建蒙脱石-碳酸盐矿化菌复合体系,研究了黏土矿物与微生物对Sr^(2+)的联合去除作用特征。结果表明,蒙脱石与碳酸盐矿化菌分别能通过吸附、微生物矿化等作用实现对Sr^(2+)的去除;Sr^(2+)的去除率与蒙脱石投加量呈正比,复合体系中两者在不同时间的作用效果不同,蒙脱石对Sr^(2+)的吸附作用随时间的增加而降低,而碳酸盐矿化菌对其矿化率随时间的增加而升高;在初始Sr^(2+)浓度为1100.19 mg/L条件下,蒙脱石投加量为40 g/L的单一体系对Sr^(2+)的最高去除率仅为28.48%,蒙脱石-碳酸盐矿化菌复合体系对Sr^(2+)的去除率高达97.92%。因此,构建的蒙脱石-碳酸盐矿化菌体系能有效实现Sr^(2+)的高效去除。

东胜铀矿床中主要微生物成矿因素实验研究

为研究砂岩型铀矿成矿过程中的主要微生物因素,对东胜砂岩型铀矿直罗组不同地球化学蚀变带中岩石样品进行生物学分析,发现各亚带中分布着不同种属的微生物,它们在铀矿床中的分布呈现一定的地球化学分带性,硫酸盐还原菌为其中的优势菌群,其中过渡带和矿石带中以具芽孢的Desulfotomaculumorientis为主;通过其对铀试剂的还原实验发现,Desulfotomaculum orientis是还原能力最强的细菌种属,且芽孢菌比例和铀矿分布呈现正相关性,通过进一步模拟实验证明,天然铀矿环境中的Desulfotomaculum orientis和模拟实验培养的菌体芽孢比例拟合度较高,证明Desulfotomaculum orientis是铀矿成矿中主要的微生物因素,它们在利用矿床中的营养成分增殖过程中可以将U(VI)还原为U(IV)并沉淀析出,促进矿床的形成。研究结果可对铀矿的生物成矿作用提供参考,同时对于生物找矿工作具有指导意义。

酸性矿山废水环境中重金属的污染特征和机制

酸性矿山废水(AMD)是矿区中常见的环境污染问题。论文以石人嶂矿区为研究对象,分析了AMD水体的污染特征、沉积物中重金属的形态及其释放风险,研究结果表明,该矿区AMD中存在以As、Zn、Cu和Fe为主的多金属复合污染。沉积物中的次生铁矿物能够固定水体中的重金属,且其固定As的能力强于Zn、Cu和Cd。在pH<3时,次生铁矿物为黄钾铁矾、砷铁石等结晶度强的铁矿物,沉积物中的重金属主要呈晶型铁结合态和残渣态,重金属的稳定性强;而在pH>3时,次生铁矿物为施氏矿物、四方水铁矿等结晶度差的铁矿物,沉积物中重金属的形态主要为表面吸附态和弱结晶铁结合态,重金属的稳定性相对较低。另外,pH>3的沉积物中含有相对丰度较高的铁还原菌,它们可能会诱导次生铁矿物相转化和重金属迁移。研究结果对厘清AMD环境中重金属的地球化学行为有重要意义。

东太平洋铁锰结核区微生物的丰度及其成矿作用研究

于1994年4－11月在东太平洋铁锰结核勘探区，随向阳红09号船，采集了39个表层沉积物、12个上覆水和7个结核样。在现场用平板法测定了异养细菌和铁、锰细菌丰度，用稀释法（MPN法）测定硫酸盐还原菌丰度。在实验室对船上带回的异养细菌和锰细菌进一步纯化分离，进行了12项生化试验，参照伯杰氏手册第八版鉴定至昆。为了探讨微生物在大洋成矿过程的作用，使用分光光度法，测定锰细菌对锰、铁离子的转化作用和不同培养温度对转化作用的影响。结果表明，在微生物丰度方面，沉积物中异养细菌的丰度在3－9500cell／g；锰、铁细菌的丰度在1×10°－103cell／g；硫酸盐还原细菌的丰度分布范围在0－4000cell／g。在上覆水和结核样中各类细菌的丰度均较低，比沉积物样低1个数量级。在细菌的菌属组成与近海区相比存在一定的差异，特别是在革兰氏阳性菌的组成上微球菌占了绝对优势。在成矿作用方面，锰细菌对锰、铁氧化还原的实验结果表明，在好氧的条件下，锰细菌使可溶性的Mn2+氧化为Mn4+,其氧化速度与环境温度存在密切关系；锰细菌对铁的氧化速度比对锰的氧化速度来得快。在厌氧的培养条件下，锰细菌能将高价铁还原为低价铁，而且使培养液的pH明显降低。