Biosorption mechanism of Cr (Ⅵ) onto cells of Synechococcus sp.

The biosorption mechanism of Cr (Ⅵ) ions on Synechococcus sp. biosorbent was studied by analyzing the biosorption kinetics as well as speciation change and bond formation during the biosorption process. The kinetics study shows that the adsorption process of Cr (Ⅵ) consists of a very fast stage in the first several minutes, in which more than half of the saturation adsorption is attained, and a slower stage that approximately follows the first order kinetic model, basically Freundlich isotherm models were observed. Comparative studies of FT-IR spectra of K_2Cr_2O_7, free cells of Synechococcus sp., and Cr-bound cells of Synechococcus sp. show that the speciation of chromium that binds to the cells of Synechococcus sp. is Cr (Ⅲ), instead of Cr (Ⅵ), and the carboxylic, alcoholic, amido and amino groups may be involved in the binding of Cr (Ⅲ). Integrative analyses of the surface electric potential, the effect of pH value on adsorption behavior of Cr (Ⅵ), and the results of FT-IR show that the biosorption of Cr (Ⅵ) follows two subsequent steps, biosorption of Cr_2O_(7~)2-))by electrostatical force at the protonated active sites and reduction of Cr_2O_(7~(2-)) to Cr3+ by the reductive groups on the surface of the biosorbents.     

SRB菌的分离鉴定及其对矸石山酸性废水的处理

为了得到煤矸石山酸性废水处理的专属功能微生物,从湖南湘潭某煤矸石山周边土壤中分离筛选硫酸盐还原菌,分析菌株的16S rRNA基因序列,形态和生理生化特性,并利用得到的菌株处理矸石山酸性废水。16S rRNA基因序列分析表明,所分离得到的硫酸盐还原菌株S-7与Desulfuromonas alkenivorans同源性达到99.0%。该菌株为杆状稍有弯曲,能运动,大小(0.5~0.8)μm×(3.0~4.0)μm,革兰氏染色显阴性,最适生长温度为30℃,最适p H值范围6~8,酵母粉为最好的碳源和氮源,硫酸钠为最适合硫源,菌株经培养96 h后细胞浓度高达1.76×109个/m L。培养初始p H为7时,6 d可去除体系中90%硫酸根离子,而不同硫酸根离子浓度对菌株生长和硫酸盐去除效率影响不明显。S-7菌株对矸石山酸性废水中Fe,Mn,Pb和Zn四种重金属离子均存在处理效果,整体上去除效率为PbFeZnMn,其中Pb离子经7 d处理后去除率达到100%。     

酿造废水处理系统中微生物多样性的分析

利用PcR_DGGE技术,对酿造废水处理系统的微生物多样性进行分析研究。分别对厌氧罐中活性污泥以及加入酿造废水后不同时间段的活性污泥进行微生物总DNA提取,特异扩增16SrDNA基因的V4-6可变区,并结合DGGE技术,对优势条带进行克隆测序及序列分析。结果表明：酿造废水厌氧处理系统中的微生物种类较为丰富,但有明显的优势种群,在不同时间段微生物多样性丰度也有明显变化。DGGE图谱中17优势条带测序比对后,初步确定了12种菌属。     

赵庄井田产甲烷菌群富集与产气条件优化

赵庄煤层气井水中富集产甲烷菌群,可优化产气能力。采用厌氧富集得到本源菌群,通过正交试验优化产气条件。水样中存在产甲烷菌群,实验室条件下最优产气条件:NH₄Cl为1.0 g/L,K₂HPO₄为1.5 g/L,MgCl₂为0.1 g/L,煤粉添加量160 g/L,60 d产甲烷量达18.07%。赵庄井田产甲烷菌群通过富集可以降解无烟煤产气,通过条件优化可提高其降解无烟煤产气的能力。     

Growth and surface properties of new thermoacidophilic Archaea strain Acidianus manzaensis YN-25 grown on different substrates

The growth and surface properties of new thermoacidophilic Archaea strain Acidianus manzaensis YN-25 isolated from an acid hot spring in Tengchong,Yunnan Province,China were investigated cultured on different substrates including soluble substrate ferrous sulfate and nonsoluble solid substrates S~0,pyrite and chalcopyrite.The growth characteristics of the cells in each substrate were characterized with the changes in cell number,pH,E_h,and concentrations of Fe~(2+)or SO_4~(2-),or ratios of[Fe~(2+)]to[Fe~...     

煤层气生物工程研究进展

煤层气生物工程是将营养液或经过驯化、改良的菌种注入地下煤层或通过地面发酵产气的方式,把煤的部分有机组分转化为甲烷,实现微生物强化煤层气产出的一种特殊发酵工程。该工程作为多学科交叉的新兴边缘学科,涉及到能源、环境和新材料三大领域,具有多重效益,越来越受到关注,详细总结了国内外煤层气生物工程10余年的发展历程,首先从煤层(水)的生物多样性、厌氧发酵系统产气机制和控制因素等方面系统分析了煤层气生物工程的微生物学基础;以研究厌氧发酵系统中气固液菌为核心,整合其他学科的研究方法,初步形成了煤层气生物工程自身的研究方法,最后提出了煤层气生物工程的实施方案及发展趋势。生物多样性为煤层生物甲烷的生成提供了菌种来源,根据发酵系统中气固液菌的变化规律将发酵过程区分为4个阶段,系统中的底物和环境因子控制了微生物群落结构,影响了生物甲烷的产量,甲烷的成因区分为乙酸营养型、氢营养型、甲基营养型3种,这一认识初步构成了煤层气生物工程的理论基础。分子生物学、地球化学与煤化学等的结合为该学科的发展提供了方法支撑。地面发酵池产气工程除了获取生物甲烷这一洁净能源外,还可以与褐煤提质、高硫煤微生物脱硫和新材料合成相结合,使得经济效益最大化;地下煤层气生物工程以其增气、增解、增透作用可大幅度提升煤层气井的产量,并获取液相有机物,同时可以实现二氧化碳的甲烷化,二氧化碳矿化对采空区可起到固化作用,减排效果显著。煤层气生物工程以其理论性、方法性和实用性正在成为一个全新的领域,将有力推进中国煤层气大规模商业化开发进程。     

广东梅州浸矿细菌的选育及对金属硫化矿的浸出

从中国南方典型矿区——广东梅州玉水生物提铜示范基地酸性矿水中分离得到一株金属硫化矿浸出微生物YS-1.对菌株YS-1的形态、生理生化特征、16S rDNA种系序列以及对黄铁矿和铁闪锌矿的浸出等进行了研究.结果表明：细菌长1.0～2.5μm,直径0.4～0.6μm,能运动,革兰氏染色显阴性,最适宜生长的pH和温度分别为2.0和30℃,能利用亚铁盐、单质硫和硫代硫酸钠,不能利用有机能源,与嗜酸氧化亚铁硫杆菌的16S rDNA种系序列同源性达到98%,对铁闪锌矿和黄铁矿的浸出率分别为14.38%和3.8%.     

Biosorption mechanism of Cr （Ⅳ） onto cells of Synechococcus sp.

The biosorption mechanism of Cr （Ⅳ） ions on Synechococcus sp. biosorbent was studied by analyzing the biosorption kinetics as well as speciation change and bond formation during the biosorption process. The kinetics study shows that the adsorption process of Cr （Ⅳ） consists of a very fast stage in the first several minutes, in which more than half of the saturation adsorption is attained, and a slower stage that approximately follows the first order kinetic model, basically Freundlich isotherm models were observed. Comparative studies of FT-LR spectra of K2Cr2O7, free cells of Synechococcus sp., and Cr-bound cells of Synechococcus sp show that the speciation of chromium that binds to the cells ofSynechococcus sp. is Cr （Ⅲ）, instead of Cr （Ⅳ）, and the carboxylic, alcoholic, amido and amino groups may be involved in the binding of Cr （Ⅲ）. Integrative analyses of the surface electric potential, the effect of pH value on adsorption behavior of Cr （Ⅵ）, and the results of FT-IR show that the biosorption of Cr （Ⅵ） follows two subsequent steps, biosorption of Cr2O7 ^2- by electrostatical force at the protonated active sites and reduction of Cr2O7^2- to Cr^3＋ by the reductive groups on the surface of the biosorbents.     

龙泉煤层气田产甲烷菌群富集的厌氧产气中试研究

为探讨龙泉煤层气田产甲烷菌群降解烟煤产甲烷的潜力,研究富集并驯化了龙泉煤层气田产甲烷菌群;以龙泉矿烟煤为母质,开展产甲烷菌群降解煤产气的实验室研究以及中试研究。结果表明,龙泉煤层产甲烷菌群经富集驯化后,降解烟煤产甲烷的浓度由8.2%上升至19.0%,且产气周期缩短。中试试验中,产甲烷浓度最高达27.06%,产甲烷速率达0.159 m L/(g·d);且在中试发酵产气的衰退期,向发酵罐内添加酵母粉、氮源、磷盐、镁盐、维生素、微量元素,可重新激活产甲烷菌群的活性,使其降解烟煤产甲烷的浓度回升。由此可见,富集驯化龙泉煤层产甲烷菌群可显著提高其降解烟煤产甲烷的能力;在发酵产气衰退期补加营养物质,可以活化产甲烷菌群,恢复其降解烟煤产甲烷的能力。     

内蒙胜利褐煤生物产气前后微生物群落变化

为研究微生物群落在褐煤生物产气过程中的作用以及产气前后煤样性质的变化。以内蒙古胜利褐煤为产气底物,寺河矿区煤层气井排出水中富集产气微生物为出发菌群,在实验室开展褐煤生物产气实验,采用Illumina高通量测序平台分析产气前后微生物群落变化,并利用气相色谱、扫描电子显微镜等手段对褐煤产甲烷量和产气前后煤样物化性质及其煤表面的菌体形貌进行分析。结果表明,内蒙胜利褐煤可以被所富集得到的菌群利用并产生甲烷,产气周期为49 d,期间累计产甲烷量为83. 1 mL,净产甲烷率为7.84 mL/g煤。褐煤生物产气微生物样本中细菌群落多样性丰富,主要优势菌门为厚壁菌门(Firmicutes)、变形菌门(Proteobacteria)、WWE1、拟杆菌门(Bacteroidetes)、互养菌门(Synergistetes)和少量的脱铁杆菌门(Deferribacteres)。原始微生物群落结构多样性较高,经褐煤和基本培养基培养产气后,群落多样性降低。在微生物属水平上菌群结构变化较大,其中W22,Proteiniclasticum,VadinCA02,Tissierella_soehngenia,Clostridium, Dasulfovibrio等菌属在产气过程中发挥重要功能。内蒙胜利褐煤挥发分较高,富氢、富氧,煤表面结构松散有明显裂隙,有利于微生物附着降解,适宜进行生物产气试验。褐煤经微生物作用产气后,水分、灰分、挥发分均降低,固定碳百分比升高,H/C升高,S元素比例下降,利用扫描电镜观察到产气体系中煤表面附着大量短杆状和球状微生物,并存在类似微生物纳米导线的结构。