用硫酸盐还原菌处理重金属废水的研究

介绍了用硫酸盐还原菌处理重金属废水的几种主要方法和原理。硫酸盐还原菌处理含重金属废水主要是通过将可溶性的重金属离子转化成不溶性的金属硫化物、氢氧化物、碳酸盐的方式 ,或直接通过以菌体对重金属离子的吸附完成的。目前研究用硫酸盐还原菌处理重金属废水的主要方法有分批沉淀工艺、吸附处理工艺、化学法和硫酸盐还原菌的混合工艺、全混合处理工艺及硫酸盐还原菌的厌氧上流式污泥床和流化床工艺 ,并对其主要的工艺指标进行了比较。     

不同pH值条件下硫酸盐还原菌组成及硫酸盐还原机制分析

【目的】从海洋沉积物中富集获得硫酸盐还原菌群,改变pH值进行培养,分析pH值对硫酸盐还原性质的影响,明确菌群组成和进行硫酸盐还原功能基因预测,探究硫酸盐还原机制。【方法】分析硫酸盐还原菌群在不同pH值条件下的硫酸盐还原率,在此基础上,利用高通量测序技术和PICRUSt软件分析硫酸盐还原菌群优势菌组成及硫酸盐还原相关基因相对丰度。【结果】硫酸盐还原菌群在不同pH值培养条件下的生长和硫酸盐还原率出现显著变化(P<0.01),在pH 5.0时达到峰值,分别为0.34±0.01和96.52%±0.44%。高通量测序数据显示,pH 5.0时菌群丰富度和多样性最高,优势菌属为假单胞菌(Pseudomonas)和芽孢杆菌(Bacillus),相对丰度较高的基因为同化性硫酸盐还原相关基因。【结论】硫酸盐还原菌富集生长的最适pH 5.0,在此条件下的高硫酸盐还原率由同化性硫酸盐还原途径主导,为揭示硫酸盐还原机制提供了实验支持,并拓宽了硫酸盐还原菌实践应用方面的种质资源。     

硫酸盐还原菌净化工业废水的研究

本文报道了硫酸盐还原菌的菌学特征,以其具有吸附和絮凝作用,使工业废水得到净化。用硫酸盐还原菌处理印染废水,废水的脱色率为92．5％,COD(cr)和BOD5亦达到排放标准。对城市生活废水和含铬的电镀废水亦有很好的处理效果,各项指标分别达到了排放标准,其中净化后的电镀废水还可作为循环水使用。     

土壤腐蚀网站硫酸盐还原菌的研究

从我国东北、西北、西南和华北的的10多种土壤的苗蚀试验站的钢件周围及腐蚀产物中,分离、纯化了13株硫酸盐还原菌(SRB),测定了它们的形态、生理生化特性及氢化酶活性,据以确定我国广大地区土壤中分布的钢铁晦蚀厌氧腐蚀萄主要为普通脱硫弧菌(Desulfovibriavulgaris)和脱硫脱硫弧菌(D.desulfuricans)。他们对钢的腐蚀速率和其氧化酶活性存在着很好的相关性。     

硫酸盐还原菌检测与应用研究进展

硫酸盐还原菌是自然界存在最为广泛的细菌之一,近年来该类微生物研究日益受到国内外学者的关注。本文对硫酸盐还原菌的鉴定、量化和应用等方面的研究进展进行综述。     

一种肠道硫酸盐还原菌的增菌培养基

目的针对已经分离、纯化的肠道硫酸盐还原菌,建立一种能快速、高效地培养菌体的培养基。方法比较营养丰富的GAM肉汤与常用于培养硫酸盐还原菌的选择性培养基Postgate的培养效果,摸索在GAM肉汤中添加不同浓度的硫酸盐对两种肠道硫酸盐还原菌-Desulfovibrio desulfuricans和Desulfovibrio intestina—zis的培养效果。确定效果最佳的改良GAM培养基配方,并测定在该培养基中D．desulful＇icans的生长曲线。结果与Postgate培养基相比,GAM肉汤能在2d内快速培养D．desulfugicans,但培养至6d时细菌数量大幅降低。在GAM肉汤中添加Na2SO4与FeSO4,在实验浓度范围内,均显著地促进硫酸盐还原菌的生长。在此基础上改良GAM肉汤培养基,培养得到的细菌数量较GAM肉汤显著提高。D．desulfuricans的生长曲线显示,2d时细菌生长达到最高峰,数量可达3．5×10^7 CFU／mL;培养6d,细菌数量为7．3×10^6 CFU／mL。结论基于GAM肉汤改良而得到的增菌培养基,能快速、高效地培养肠道硫酸盐还原菌,为后续进一步研究肠道硫酸盐还原菌的生理功能提供了支持。     

硫酸盐还原菌及其还原解毒Cr(Ⅵ)的研究进展

硫酸盐还原菌是一类分布广泛, 能进行硫酸盐异化还原反应的严格厌氧菌。利用硫酸盐还原菌可去除环境中的许多污染物, 因而该类细菌在环境污染治理中具有广阔的应用前景。本文介绍了硫酸盐还原菌的生物学特性和代谢特征及其在环境污染治理中的应用, 并对硫酸盐还原菌还原解毒Cr(Ⅵ)及应用于含Cr(Ⅵ)废水处理的研究进展作了综述, 分析了其未来的研究方向。     

象山港海域硫酸盐还原菌的时空分布及其影响因素

分别于2007年7月(夏季)、11月(秋季)与2008年1月(冬季)、4月(春季),调查了象山港海域的水样(表层海水和上覆水)及沉积物中的硫酸盐还原菌丰度的时空分布特征及主要影响因素.结果表明,水样及沉积物中硫酸盐还原菌实测值的变化范围为30～2300 cells·ml-1,沉积物中的硫酸盐还原菌数量高于上覆水及表层海水;硫酸盐还原菌丰度的平面分布均呈现不均匀状态,人类开发活动较多的地区明显高于其他站点.根据硫酸盐还原菌数量,对底质进行腐蚀性评价结果表明,象山港大部分范围底质具有中等强度腐蚀性.有机质污染、水温、pH是表层海水中硫酸盐还原菌分布的重要影响因素(P＜0.01);上覆水中的硫酸盐还原菌含量与上覆水的营养盐(NO2--N、NH4+-N)呈显著正相关;沉积物中的硫酸盐还原菌含量与沉积物中的石油类呈显著正相关(P＜0.05).     

硫酸盐还原菌鉴定和检测方法的研究进展

硫酸盐还原菌有着重要的生态、经济和环境意义。系统地论述了硫酸盐还原菌鉴定和检测常用手段,如硫酸盐还原菌分离纯化培养方法、检测遗传标记的分子生物学方法和生物特征化合物方法。这些技术的发展,不断扩展了硫酸盐还原菌的研究领域和深度并使对硫酸盐还原菌在分子水平的研究成为可能。     

油田硫酸盐还原菌酸化腐蚀机制及防治研究进展

硫酸盐还原菌(Sulfate reducing bacteria,SRB)是一些厌氧产硫化氢的细菌的统称,是以有机物为养料的厌氧菌。它们广泛分布于pH值6-9的土壤、海水、河水、淤泥、地下管道、油气井、港湾及锈层中,它们生存于好气性硫细菌产生的沉积物下,其最适宜的生长温度是20-30℃,可以在高达50-60℃的温度下生存,与腐蚀相关的最主要的是脱硫脱硫弧菌(Desulfovibrio desulfuricans)。 它们是许多腐蚀问题的主因,例如油田系统金属管路的腐蚀等。在海上油田生产中,海水常被注入油井用于进行2次采油。富含硫酸盐的海水能加速油藏中SRB的生长,随之H₂S大量产生,引起油田水的酸化,H₂S具有毒性和腐蚀性,增加石油和天然气中的硫含量,并可能引起油田堵塞。SRB引起的腐蚀问题是拭待解决的最主要问题。国内外治理该问题的途径主要有物理杀灭、添加化学杀菌剂等方法,但是这些方法成本高,持续效果不显著。近几年来国外学者开始重点关注利用生物竞争排斥技术(Bio-competitive inhibition technology,BCX)控制硫酸盐还原菌的生长代谢的方法,该方法的原理为通过加入特定的药剂,激活油藏中的本源微生物或加入外源微生物,使其与SRB竞争营养源或产生代谢物抑制SRB的生长代谢,进而抑制H₂S的产生。GMT-LATA的科学家对在厌氧油气储层和开采系统中硝酸盐还原菌的作用进行了最早的研究,认为该细菌可以抑制硫酸盐还原菌的代谢活动。随后BCX技术已经在国外部分油田得到了应用,国内还没有在海油生产中应用的报道,但是也有学者对该方法进行了研究。     

Distribution of Methanogenic and Sulfate-Reducing Bacteria in Near-Shore Marine Sediments

The distribution of methanogenic and sulfate-reducing bacteria was examined in sediments from three sites off the coast of eastern Connecticut and five sites in Long Island Sound. Both bacterial groups were detected at all sites. Three distributional patterns were observed: (i) four sites exhibited methanogenic and sulfate-reducing populations which were restricted to the upper 10 to 20 cm, with a predominance of sulfate reducers; (ii) three sites in western Long Island Sound exhibited a methanogenic population most abundant in sediments deeper than those occupied by sulfate reducers; (iii) at one site that was influenced by fresh groundwater, methanogens and sulfate reducers were numerous within the same depths; however, the number of sulfate reducers varied vertically and temporally with sulfate concentrations. It was concluded that the distributions of abundant methanogenic and sulfate-reducing bacteria were mutually exclusive. Methanogenic enrichments yielded all genera of methanogens except Methanosarcina, with the methanobacteria predominating.     

Diversity and Characterization of Sulfate-Reducing Bacteria in Groundwater at a Uranium Mill Tailings Site

Microbially mediated reduction and immobilization of U(VI) to U(IV) plays a role in both natural attenuation and accelerated bioremediation of uranium-contaminated sites. To realize bioremediation potential and accurately predict natural attenuation, it is important to first understand the microbial diversity of such sites. In this paper, the distribution of sulfate-reducing bacteria (SRB) in contaminated groundwater associated with a uranium mill tailings disposal site at Shiprock, N.Mex., was investigated. Two culture-independent analyses were employed: sequencing of clone libraries of PCR-amplified dissimilatory sulfite reductase (DSR) gene fragments and phospholipid fatty acid (PLFA) biomarker analysis. A remarkable diversity among the DSR sequences was revealed, including sequences from δ-Proteobacteria, gram-positive organisms, and the Nitrospira division. PLFA analysis detected at least 52 different mid-chain-branched saturate PLFA and included a high proportion of 10me16:0. Desulfotomaculum and Desulfotomaculum-like sequences were the most dominant DSR genes detected. Those belonging to SRB within δ-Proteobacteria were mainly recovered from low-uranium (≤302 ppb) samples. One Desulfotomaculum-like sequence cluster overwhelmingly dominated high-U (>1,500 ppb) sites. Logistic regression showed a significant influence of uranium concentration over the dominance of this cluster of sequences (P = 0.0001). This strong association indicates that Desulfotomaculum has remarkable tolerance and adaptation to high levels of uranium and suggests the organism's possible involvement in natural attenuation of uranium. The in situ activity level of Desulfotomaculum in uranium-contaminated environments and its comparison to the activities of other SRB and other functional groups should be an important area for future research.     

Distribution of Iron-Oxidizing Bacteria in the Nordic Uranium Tailings Deposit, Elliot Lake, Ontario, Canada

Iron-oxidizing bacteria are present within the top 2 m (but not always at the surface) and near the water table-capillary fringe of the vegetated Nordic uranium deposit, Elliot Lake, Ontario, Canada. They are distributed uniformly in the top 0.5 m of unvegetated tailings. The locations of these bacteria correlate with zones of pyrite oxidation as delineated in previous studies by the formation of soluble iron and sulfate. Heterotrophic bacteria are also present in the tailings, with greatest concentrations at the surface and near the water table-capillary fringe. Sulfate-reducing bacteria were detected in the soil and peat at the base of the tailings. The results of this study suggest that the establishment of vegetation directly upon the tailings surface does not arrest bacterial pyrite oxidation.     

Modeling Reduction of Uranium U(VI) under Variable Sulfate Concentrations by Sulfate-Reducing Bacteria

The kinetics for the reduction of sulfate alone and for concurrent uranium [U(VI)] and sulfate reduction, by mixed and pure cultures of sulfate-reducing bacteria (SRB) at 21 ± 3°C were studied. The mixed culture contained the SRB Desulfovibrio vulgaris along with a Clostridium sp. determined via 16S ribosomal DNA analysis. The pure culture was Desulfovibrio desulfuricans (ATCC 7757). A zero-order model best fit the data for the reduction of sulfate from 0.1 to 10 mM. A lag time occurred below cell concentrations of 0.1 mg (dry weight) of cells/ml. For the mixed culture, average values for the maximum specific reaction rate, V_max, ranged from 2.4 ± 0.2 μmol of sulfate/mg (dry weight) of SRB · h⁻¹) at 0.25 mM sulfate to 5.0 ± 1.1 μmol of sulfate/mg (dry weight) of SRB · h⁻¹ at 10 mM sulfate (average cell concentration, 0.52 mg [dry weight]/ml). For the pure culture, V_max was 1.6 ± 0.2 μmol of sulfate/mg (dry weight) of SRB · h⁻¹ at 1 mM sulfate (0.29 mg [dry weight] of cells/ml). When both electron acceptors were present, sulfate reduction remained zero order for both cultures, while uranium reduction was first order, with rate constants of 0.071 ± 0.003 mg (dry weight) of cells/ml · min⁻¹ for the mixed culture and 0.137 ± 0.016 mg (dry weight) of cells/ml · min⁻¹ (U₀ = 1 mM) for the D. desulfuricans culture. Both cultures exhibited a faster rate of uranium reduction in the presence of sulfate and no lag time until the onset of U reduction in contrast to U alone. This kinetics information can be used to design an SRB-dominated biotreatment scheme for the removal of U(VI) from an aqueous source.     

Distribution of Sulfate-Reducing and Methanogenic Bacteria in Anaerobic Aggregates Determined by Microsensor and Molecular Analyses

Using molecular techniques and microsensors for H₂S and CH₄, we studied the population structure of and the activity distribution in anaerobic aggregates. The aggregates originated from three different types of reactors: a methanogenic reactor, a methanogenic-sulfidogenic reactor, and a sulfidogenic reactor. Microsensor measurements in methanogenic-sulfidogenic aggregates revealed that the activity of sulfate-reducing bacteria (2 to 3 mmol of S²⁻ m⁻³ s⁻¹ or 2 × 10⁻⁹ mmol s⁻¹ per aggregate) was located in a surface layer of 50 to 100 μm thick. The sulfidogenic aggregates contained a wider sulfate-reducing zone (the first 200 to 300 μm from the aggregate surface) with a higher activity (1 to 6 mmol of S²⁻ m⁻³ s⁻¹ or 7 × 10⁻⁹ mol s⁻¹ per aggregate). The methanogenic aggregates did not show significant sulfate-reducing activity. Methanogenic activity in the methanogenic-sulfidogenic aggregates (1 to 2 mmol of CH₄ m⁻³ s⁻¹ or 10⁻⁹ mmol s⁻¹ per aggregate) and the methanogenic aggregates (2 to 4 mmol of CH₄ m⁻³ s⁻¹ or 5 × 10⁻⁹ mmol s⁻¹ per aggregate) was located more inward, starting at ca. 100 μm from the aggregate surface. The methanogenic activity was not affected by 10 mM sulfate during a 1-day incubation. The sulfidogenic and methanogenic activities were independent of the type of electron donor (acetate, propionate, ethanol, or H₂), but the substrates were metabolized in different zones. The localization of the populations corresponded to the microsensor data. A distinct layered structure was found in the methanogenic-sulfidogenic aggregates, with sulfate-reducing bacteria in the outer 50 to 100 μm, methanogens in the inner part, and Eubacteria spp. (partly syntrophic bacteria) filling the gap between sulfate-reducing and methanogenic bacteria. In methanogenic aggregates, few sulfate-reducing bacteria were detected, while methanogens were found in the core. In the sulfidogenic aggregates, sulfate-reducing bacteria were present in the outer 300 μm, and methanogens were distributed over the inner part in clusters with syntrophic bacteria.     

Diversity and Distribution of Sulfate-Reducing Bacteria in Permanently Frozen Lake Fryxell, McMurdo Dry Valleys, Antarctica

The permanently frozen freshwater Lake Fryxell, located in the Dry Valleys of Antarctica, exhibits an ideal geochemistry for microbial sulfate reduction. To investigate the population of sulfate-reducing bacteria in Lake Fryxell, both 16S rRNA gene and metabolic primer sets targeting the dsrA gene for the dissimilatory sulfite reductase alpha subunit were employed to analyze environmental DNA obtained from the water column and sediments of Lake Fryxell. In addition, enrichment cultures of sulfate-reducing bacteria established at 4°C from Lake Fryxell water were also screened using the dsrA primer set. The sequence information obtained showed that a diverse group of sulfate-reducing prokaryotes of the domain Bacteria inhabit Lake Fryxell. With one exception, the enrichment culture sequences were not represented within the environmental sequences. Sequence data were compared with the geochemical profile of Lake Fryxell to identify possible connections between the diversity of sulfate-reducing bacteria and limnological conditions. Several clone groups were highly localized with respect to lake depth and, therefore, experienced specific physiochemical conditions. However, all sulfate-reducing bacteria inhabiting Lake Fryxell must function under the constantly cold conditions characteristic of this extreme environment.     

Response Characteristics between Sulfate-Reducing Bacteria and Environmental Factors in Petroleum Hydrocarbon-Contaminated Field of Northeast China

Lithology samples were collected from six sites of a petroleum hydrocarbon-contaminated site in northeast China along a contamination plume. The sulfate-reducing bacteria (SRB) diversity of all samples was analyzed by PCR-DGGE technology. The Shannon-Wiener indexes (1.004–3.665), Simpson indexes (0.516–0.907) and Pielou indexes (0.996–1.004) of all samples were used to characterize the abundances, advantages and evenness of the microbial communities. Additionally, Canoco for Windows 4.5 was utilized to analyze the correlation between dominant SRB and environmental factors. The results showed that the abundance, advantages and evenness of the sulfate-reducing bacterial community changed regularly along the contamination plume direction. The microbial homology of the samples was not high (0.25–0.80), and the dominant bacteria exhibited heteroplasmy. Additionally, the dominant bacteria were identified as uncultured bacteria. Canonical correspondence analysis (CCA) analysis showed that the distribution and structure of SRB communities were not obviously correlated with the concentration of total petroleum hydrocarbons (TPH), dissolved oxygen (DO) and other environmental factors. The results presented herein provide evidence of natural bioremediation in petroleum hydrocarbon-contaminated fields and information that will be useful to bioremediation of other contaminated fields.     

Formation of Ni- and Zn-Sulfides in Cultures of Sulfate-Reducing Bacteria

The purpose of this study was to characterize Ni- and Zn-sulfides precipitated in sulfate-reducing bacterial cultures. Fe-free media containing 58 mM SO ₄ ^2? were amended with Ni and Zn chloride followed by inoculation. Precipitates were sampled from cultures after two weeks of incubation at 22, 45, and 60 ^° C. Abiotic controls were prepared by reacting bacteria-free liquid media with Na ₂ S solutions under otherwise identical conditions. Precipitates were collected anaerobically, freeze-dried and analyzed by x-ray diffraction (XRD), scanning electron microscopy, and for total Ni, Zn, and S. In Ni-containing media, biogenic sulfide precipitates were mostly heazelwoodite (Ni ₃ S ₂ ), whereas abiotic precipitates were mixed heazelwoodite and vaesite (NiS ₂ ). The biogenic Ni-precipitates were better crystalline than the corresponding abiotic samples. Sphalerite (ZnS) was identified by XRD in precipitates sampled from Zn-containing media. Scanning electron microscopy revealed disordered morphological features for the sulfides, which occurred mostly as aggregates of fine particles in biogenic samples, whereas abiotic precipitates contained more plate- and needle-like structures.