固定化SRB包埋颗粒组分优选及处理含SO_(4)^(2-)废水效果研究

赣南离子型稀土矿尾水存在SO42-含量高、pH偏低的问题,影响后续微生物对尾水其他组分(NH_(4)^(+)-N、NO_(3)^(-)-N)的处理,拟采用硫酸盐还原菌(SRB)包埋颗粒对水体中SO_(4)^(2-)进行去除,同时提升水体pH。通过对SRB包埋颗粒表面吸附材料、还原激活材料、内聚碳源和固体酸水解材料4个组分进行实验研究优选SRB包埋颗粒组分,结果表明,凹凸棒石粉作为SRB包埋颗粒表面吸附材料应用效果比较好,纳米零价铁对SRB的还原激活作用相对更好,内聚碳源及固体酸水解材料组合以玉米芯、花生壳与沸石粉、磁铁矿粉的组合效果比较理想。在此基础上筛选制备出4种包埋颗粒,通过厌氧三角瓶验证其对模拟废水中SO_(4)^(2-)的去除效果,发现制备的4种包埋颗粒经过10 d的实验对SO_(4)^(2-)的去除率都在60%以上,去除率最高的是花生壳-Fe_(3)O_(4)组合包埋颗粒,为80.20%。

SURFACE ANALYSIS OF ALUMINUM ALLOYS INFLUENCED BY SULFATE- REDUCING BACTERIA

The morphology and chemical compositions of surface and corrosion phases for two aluminum alloys(7075 and 2024 ) in the aqueous mediums containing sulfate reducing bacteria(SRB) were studied by the methods of scanning electron microscopy (SEM) and energy dispersive x ray analysis (EDXA). The results showed that serious pitting corrosion took place when aluminum alloys were exposed in the mediums containing SRB, whereas no pitting corrosion were found on the surfaces of aluminum alloys only exposed in blank mediums non containing SRB. It was demonstrated with EDXA that corrosion of aluminum alloys exposed in the solutions containing SRB, whereas the corrosion in the solution non containing microorganisms was attributed to the presence of chloride ions(Cl ).

Treatment of simulated wastewater from in situ leaching uranium mining by zerovalent iron and sulfate reducing bacteria

Batch and column experiments were conducted to determine whether zerovalent iron (ZVI) and sulfate reducing bacteria (SRB) can function synergistically and accelerate pollutant removal. Batch experiments suggest that combining ZVI with SRB can enhance the removal of U(Ⅵ) synergistically. The removal rate of U(Ⅵ) in the ZVI+SRB combining system is obviously higher than the total rate of ZVI system and SRB system with a difference of 13.4% at t=2 h and 29.9% at t=4 h. Column experiments indicate that the reactor filled with both ZVI and SRB biofilms is of better performance than the SRB bioreactor in wastewater basification, desulfurization and U(Ⅵ) fixation. The results imply that the ZVI+SRB permeable reactive barrier may be a promising method for treating subsurface uranium contamination.

Cd^(2+) removal from wastewater by sulfate reducing bacteria with an anaerobic fluidized bed reactor

A process of treatment for containing Cd 2+ wastewater by sulfate reducing bacteria with upflow anaerobic fluidized bed reactor has been studied. When the concentration of COD and Cd 2+ in the influent were 270 5mg/L and 100mg/L respectively and hydraulic retention time was 4 hours, the removal rate of COD and Cd 2+ were higher than 73 8% and 99 8% respectively. The reactor can treat as high as 1000mg/L of concentration of Cd 2+ . The highest removal velocity rate of Cd 2+ reached 2999 1mg/(L·d). And the possible relationship between sulfate reducing bacteria and methanogenic bacteria was discussed.

Molecular Characterization of Sulfate-Reducing Bacteria Community in Surface Sediments from the Adjacent Area of Changjiang Estuary

Sulfate-reducing bacteria(SRB),which obtain energy from dissimilatory sulfate reduction,play a vital role in the carbon and sulfur cycles.The dissimilatory sulfite reductase(Dsr),catalyzing the last step in the sulfate reduction pathway,has been found in all known SRB that have been tested so far.In this study,the diversity of SRB was investigated in the surface sediments from the adjacent area of Changjiang Estuary by PCR amplification,cloning and sequencing of the dissimilatory sulfite reductase beta subunit gene(dsr B).Based on dsr B clone libraries constructed in this study,diversified SRB were found,represented by 173 unique OTUs.Certain cloned sequences were associated with Desulfobacteraceae,Desulfobulbaceae,and a large fraction(60%) of novel sequences that have deeply branched groups in the dsr B tree,indicating that novel SRB inhabit the surface sediments.In addition,correlations of the SRB assemblages with environmental factors were analyzed by the linear model-based redundancy analysis(RDA).The result revealed that temperature,salinity and the content of TOC were most closely correlated with the SRB communities.More information on SRB community was obtained by applying the utility of Uni Frac to published dsr B gene sequences from this study and other 9 different kinds of marine environments.The results demonstrated that there were highly similar SRB genotypes in the marine and estuarine sediments,and that geographic positions and environmental factors influenced the SRB community distribution.

The Dynamic Experiment on Treating Acid Mine Drainage with Iron Scrap and Sulfate Reducing Bacteria Using Biomass Materials as Carbon Source

The study is aimed at the problem of high content of Cr^(6+),Cr^(3+)and SO_(4)^(2-)is high and low pH value in acid mine drainage(AMD).Moreover,treatment of AMD by sulfate reducing bacteria(SRB)requires the addition of carbon source,while the treating effectiveness is not good enough on its own.The sugarcane slag,the corn cob and the sunflower straw were selected as the SRB carbon source cooperating with iron scrap to construct the dynamic columns 1,2 and 3.The mechanism of removing Cr^(6+),Cr^(3+),SO_(4)^(2-)and H+and the regularity of sustained release of carbon source and TFe release was studied in AMD.The removal efficiency of heavy metal ions,the ability of sustained release of carbon source,and the ability of adjusting acid by the three dynamic columns were compared.The result shows that the average removal rates of Cr^(6+),Cr^(3+)and SO_(4)^(2-)in effluent of dynamic column 1,filled by sugarcane slag,iron scrap and SRB,were 96.9%,67.1%and 54.3%.The average release of TFe and chemical oxygen demand(COD)were 4.4 and 287.3 mg/L.Its average pH was 6.98.Compared with the performance of dynamic columns 1,2 and 3,dynamic column 1 performed best in removing Cr^(6+),Cr^(3+)and SO_(4)^(2-)from AMD and controlling the release of COD and TFe,adjusting the pH of the solution.The study is of significance in treatment of AMD by taking for biomass materials as SRB carbon source in cooperation with iron scrap.

Analysis of cultivable aerobic bacterial community composition and screening for facultative sulfate-reducing bacteria in marine corrosive steel

Anaerobic, aerobic, and facultative bacteria are all present in corrosive environments. However, as previous studies to address corrosion in the marine environment have largely focused on anaerobic bacteria, limited attention has been paid to the composition and function of aerobic and facultative bacteria in this process. For analysis in this study, ten samples were collected from rust layers on steel plates that had been immersed in seawater for diff erent periods (i.e., six months and eight years) at Sanya and Xiamen, China. The cultivable aerobic bacterial community structure as well as the number of sulfate-reducing bacteria (SRB) were analyzed in both cases, while the proportion of facultative SRB among the isolated aerobic bacteria in each sample was also evaluated using a novel approach. Bacterial abundance results show that the proportions are related to sea location and immersion time;abundances of culturable aerobic bacteria (CAB) and SRB from Sanya were greater in most corrosion samples than those from Xiamen, and abundances of both bacterial groups were greater in samples immersed for six months than for eight years. A total of 213 isolates were obtained from all samples in terms of CAB community composition, and a phylogenetic analysis revealed that the taxa comprised four phyla and 31 genera. Bacterial species composition is related to marine location;the results show that Firmicutes and Proteobacteria were the dominant phyla, accounting for 98.13% of the total, while Bacillus and Vibrio were the dominant genera, accounting for 53.06% of the total. An additional sixfacultative SRB strains were also screened from the isolates obtained and were found to encompass the genus Vibrio (four strains), Staphylococcus (one strain), and Photobacterium (one strain). It is noteworthy that mentions of Photobacterium species have so far been absent from the literature, both in terms of its membership of the SRB group and its relationship to corrosion.

Removal of SO_4^(2-),uranium and other heavy metal ions from simulated solution by sulfate reducing bacteria

在在原处铀沥滤的情况中，自从 leachant 被注入忍受铀沉积物的水，为地下水的原始 geochemical 环境被改变。这增加 SO42 的集中 ? ，在地下水污染的铀和另外的重金属离子和结果。SO42 的减小上的模仿的解决方案的 pH 值的效果？并且由减少细菌(SRB ) 的硫酸盐的铀和另外的重金属离子的移动被学习。结果看那模仿的答案的 pH 价值是否是大约 8， SO42 的减小率吗？由 SRB 和铀的移动率， Mn2+ ， Zn2+ ， Pb2+ 和 Fe2+ 将到达他们的最高的价值。为在在原处沥滤的地下水的补习的一种 bioremediation 技术铀矿能被开发。

Diversity and community pattern of sulfate-reducing bacteria in piglet gut

Background: Among the gut microbiota,sulfate-reducing bacteria(SRB) is a kind of hydrogen-utilizing functional bacteria that plays an important role in intestinal hydrogen and sulfur metabolism.However,information is lacking regarding diversity and community structure of SRB in the gut of piglets.Middle cecum contents were collected from 6 Yorkshire and 6 Meishan piglets at postnatal days(PND) 14,28 and 49.Piglets were weaned at PND28.Real-time quantitative PCR was performed to detect the number of SRB in the cecum based on dissimilatory sulfite reductase subunit A(dsrA) gene.Prior to real-time PCR,plasmid containing the dsrA gene was constructed and used as external standard to create a standard curve,from which the gene copies of dsrA were calculated.H2S concentration in the cecal contents was measured.Illumina PE250 sequencing of dsrA gene was used to investigate SRB diversity in cecum contents.Results: The qPCR results showed that the number of SRB at PND49 was significantly higher than that at PND28 in Meishan piglets.The concentration of H2S has no significant difference between piglet breeds and between different ages.The Illumina sequencing analysis revealed that the Chao1 richness index was significantly higher at PND49 than that at PND14 and PND28 in Yorkshire piglets.Based on dsrA gene similarities,Proteobacteria,Actinobacteria,and Firmicutes were identified at the phylum level,and most sequences were classified as Proteobacteria.At the genus level,most of sequences were classified as Desulfovibrio.At the species level,Desulfovibrio intestinalis was the predominant SRB in the piglet cecum.The relative abundance and the inferred absolute abundance of Faecalibacterium prausnitzii at PND49 were significantly higher than that at PND14 in Yorkshire piglets.Pig breeds did not affect the dsrA gene copies of SRB,diversity index and community pattern of SRB.Conclusions: Sulfate-reducing bacteria are widely colonized in the cecum of piglets and D.intestinalis is the dominant SRB.The age of piglets,but not the pig breeds affects the diversity and community pattern of SRB.

Effect of Sulfate-reducing Bacteria on Corrosion Behavior of Mild Steel in Sea Mud

微生物学地影响的腐蚀( MIC )是在它是的海泥 environment.Therefore 下面埋葬的很严重的腐蚀 forconstructions 对很重要在海 mud.In 执行海洋的钢的腐蚀行为的 theinvestigation 这份报纸，海泥里的低碳钢的腐蚀行为上的效果 减少ofsulfate 细菌( SRB )被 weightloss 学习，双分隔空间的房间，电子探查微量分析( EPMA )，传播 electronmicroscopy ( TEM )

Influence of Calcareous Deposit on Corrosion Behavior of Q235 Carbon Steel with Sulfate-Reducing Bacteria

Cathodic protection is a very effective method to protect metals, which can form calcareous deposits on metal surface. Research on the interrelationship between fouling organism and calcareous deposits is very important but very limited, especially sulfate-reducing bacteria(SRB). SRB is a kind of very important fouling organism that causes microbial corrosion of metals. A study of the influence of calcareous deposit on corrosion behavior of Q235 carbon steel in SRB-containing culture medium was carried out using electrochemical impedance spectroscopy(EIS), scanning electron microscopy(SEM) and surface spectroscopy(EDS). The calcareous deposit was formed with good crystallinity and smooth surface under the gradient current density of -30 μA cm^(-2) in natural seawater for 72 h. Our results can help elucidate the formation of calcareous deposits and reveal the interrelationship between SRB and calcareous deposits under cathodic protection. The results indicate that the corrosion tendency of carbon steel was obviously affected by Sulfate-reducing Bacteria(SRB) metabolic activity and the calcareous deposit formed on the surface of carbon steel under cathodic protection was favourable to reduce the corrosion rate. Calcareous deposits can promote bacterial adhesion before biofilm formation. The results revealed the interaction between biofouling and calcareous deposits, and the anti-corrosion ability was enhanced by a kind of inorganic and organic composite membranes formed by biofilm and calcareous deposits.

Isolation and identification of a sulfate reducing bacteria and sequence analysis of its dissimilatory sulfite reductase gene

A sulfate reducing bacteria was isolated from mining sewage of Daqing Oilfield by Hungate anaerobic technology. Physiological-biochemical analysis showed that the strain could utilize polyacrylamide as sole carbon and nitrogen source. The sequence analysis of 16S rDNA illustrated that the similarity of F8 and Desulfovibrio desulfuricans (AF192153) was 99%, and the similarity sequence of dissimilatory sulfite reductase gene (DSR) cloned from the strain and Desulfovibrio desulfuricans (AF273034) was 98%. Their phylogenitic analysis was basically anastomosed, and thus temporarily named as Desulfovibrio desulfuricans F8. The DSR cloned from F8 strain was 2740 bp in length consisting of three ORF, DSRA, DSRB and DSRD as a single operon (DSRABD) regulated by the same operator. DSRA contained typical conservative box of sulfate—sulfite reducing enzyme (SiteⅠand SiteⅡ), which could bind siroheme and [Fe4S4]. DSRB retained a [Fe4S4] binding site, with an uncomplimentary structure for siroheme binding. There was no conservative box in DSRD. Sequence analysis of DSR will provide a theoretical basis for quantitative detection, metabolic pathway modification through gene engineering, and sulfate reducing bacteria (SRB) suppression.

Preparation of Conducting Poly N-methylaniline Microsphere and Its Antibacterial Performance to Sulfate Reducing Bacteria

Microspheres of conducting polymers poly N-methylaniline （PNMA） were successfully synthesized through oxidation of N-methylaniline without any template. The average diameter of the microspheres with a smooth surface was about 0.40 μm when 0.2 M N-methylanUine was oxidized with 0.2 M ammonium persulfate in 0.2 M of HClO4 solution. The size of microspheres can be controlled by changing reaction time and temperature. The acid concentration was critical for the formation of microspheres with smooth surfaces. The excellent antibacterial performance of PNMA in novolac epoxy coating to sulfate reducing bacteria was demonstrated. Moreover, in API media, PNMA inhibited growth of SRB and then reduced the corrosion rate of carbon steel remarkably.

Corrosion and Electrochemical Behavior of 316L Stainless Steel in Sulfate-reducing and Iron-oxidizing Bacteria Solutions

Corrosion and electrochemical behavior of 316L stainless steel was investigated in the presence of aerobic iron-oxidizing bacteria IOB and anaerobic sulfate-reducing bacteria SRB isolated from cooling water systems in an oil refinery using electrochemical measurement, scanning electron microscopy SEM and energy dispersive atom X-ray analysisEDAX. The results show the corrosion potential and pitting potential of 316L stainless steel decrease distinctly in the presence of bacteria, in comparison with those observed in sterile medium under the same exposure time. SEM morphologies have shown that 316L stainless steel reveals no signs of pitting attack in the sterile medium. However, micrometer-scale corrosion pits were observed on 316L stainless steel sur- face in the presence of bacteria. The presence of SRB leads to higher corrosion rates than IOB. The interactions between the stainless steel surface, abiotic corrosion products, and bacterial cells and their metabolic products in- creased the corrosion damage degree of the passive film and accelerated pitting propagation.

Electron transfer from sulfate-reducing bacteria biofilm promoted by reduced graphene sheets

Reduced graphene sheets (RGSs) mediate electron transfer between sulfate-reducing bacteria (SRB) and solid electrodes, and promote the development of microbial fuel cells (MFC). We have investigated RSG-promoted electron transfer between SRB and a glassy carbon (GC) electrode. The RGSs were produced at high yield by a chemical sequence involving graphite oxidation, ultrasonic exfoliation of nanosheets, and N2H4 reduction. Cyclic voltammetric testing showed that the characteristic anodic peaks (around 0.3 V) might arise from the combination of bacterial membrane surface cytochrome c3 and the metabolic products of SRB. After 6 d, another anodic wave gradually increased to a maximum current peak and a third anodic signal became visible at around 0 V. The enhancements of two characteristic anodic peaks suggest that RSGs mediate electron-transfer kinetics between bacteria and the solid electrode. Manipulation of these recently-discovered electron-transport mechanisms will lead to significant advances in MFC engineering.