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 analysis(EDAX). 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 surface 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 increased the corrosion damage degree of the passive film and accelerated pitting propagation.

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.

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

Microbiologically influenced corrosion （MIC） is very severe corrosion for constructions buried under sea mud environment. Therefore it is of great importance to carry out the investigation of the corrosion behavior of marine steel in sea mud. In this paper, the effect of sulfate-reducing bacteria （SRB） on corrosion behavior of mild steel in sea mud was studied by weight loss, dual-compartment cell, electronic probe microanalysis （EPMA）, transmission electron microscopy （TEM） combined with energy dispersive X-ray analysis （EDX） and electrochemical impedance spectroscopy （EIS）. The results showed that corrosion rate and galvanic current were influenced by the metabolic activity of SRB. In the environment of sea mud containing SRB, the original corrosion products, ferric （oxyhydr） oxide, transformed to iron sulfide. With the excess of the dissolved H2S, the composition of the protective layer formed of FeS transformed to FeS2 or other non-stoichiometric polysulphide, which changed the state of the former layer and accelerated the corrosion process.

Partial function prediction of sulfate-reducing bacterial community from the rhizospheres of two typical coastal wetland plants in China

Sulfate-reducing bacteria(SRB)are ubiquitous anaerobic microorganisms that play signifi cant roles in the global biogeochemical cycle.Coastal wetlands,one of the major habitats of SRB,exhibit high sulfate-reducing activity and thus play signifi cant roles in organic carbon remineralization,benthic geochemical action,and plant-microbe interactions.Recent studies have provided credible evidence that the functional rather than the taxonomic composition of microbes responds more closely to environmental factors.Therefore,in this study,functional gene prediction based on PacBio single molecular real-time sequencing of 16S rDNA was applied to determine the sulfate-reducing and organic substrate-decomposing activities of SRB in the rhizospheres of two typical coastal wetland plants in North and South China:Zostera japonica and Scirpus mariqueter.To this end,some physicochemical characteristics of the sediments as well as the phylogenetic structure,community composition,diversity,and proportions of several functional genes of the SRB in the two plant rhizospheres were analyzed.The Z.japonic a meadow had a higher dissimilatory sulfate reduction capability than the S.mariqueter-comprising saltmarsh,owing to its larger proportion of SRB in the microbial community,larger proportions of functional genes involved in dissimilatory sulfate reduction,and the stronger ability of the SRB to degrade organic substrates completely.This study confi rmed the feasibility of applying microbial community function prediction in research on the metabolic features of SRB,which will be helpful for gaining new knowledge of the biogeochemical and ecological roles of these bacteria in coastal wetlands.

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.

Synthesis of Chlorinated Bicyclic Adduct as Biocids for Sulfate-Reducing Bacteria

Synthesis of bicyclic systems containing chlorine atoms, and/or ether groups in aromatic rings can be con- sidered as an important method for building bicyclic system and production of new adducts. One of the most important types in the cycloaddition reaction is the Diels-Alder reaction (1,4 cycloaddition). In the present investigation a new ether of allylic type (dienophile) p-allyl bromo phenol was prepared and its structure was confirmed by molecular weight determination, refractive index, infrared spectra, and density. A new adduct was obtained by means of 1,4 cycloaddition reaction of hexachlorocyclopentadiene (HCP) and the new pre- pared dienophile. The reaction takes place without using solvent, catalysts, or elimination of any compound. The effect of variations in temperature, initial molar ratio and reaction duration were studied to determine the optimum conditions of the reaction. The optimum conditions reached were reaction temperature recorded 140?C, initial molar ratio diene: dienophile was 3:1 and the reaction duration time reached 6 h. Under these optimum conditions the maximum yield was 78%. The new adduct revealed very high biological effect as sulfate-reducing bacteria (SRB).

Model identification with BPNN on restrictive ecological factors of SRB for sulfate-reduction

The model of back-propagation neural network (BPNN) was presented to demonstrate the effect of restrictive ecological factors, COD/SO 4 2- ratio, pH value, alkalinity (ALK) and SO 4 2- loading rate (Ns), on sulfate reduction of Sulfate Reducing Bacteria (SRB) in an acidogenic sulfate reducing reactor supplied with molasses as sole organic carbon source and sodium sulfate as electron acceptor. The compare of experimental results and computer simulation was also discussed. It was shown that the method of BPNN had a powerful ability to analyze the ecological characteristic of acidogenic sulfate reducing ecosystem quantitatively.

厌氧处理构筑物中SRB的生态学

对处理硫酸盐废水过程中，硫酸盐还原菌（SRB）在处理构筑物中的生态学研究进行了综述。着重论述了影响SRB代谢的重要生态因子包括pH值、温度、底物资源、抑制剂等），SRB与MPB和AB对H2和乙酸、VFA等共同底物的竞争利用，并介绍了不同SRB种群对底物的竞争，指出对SRB生态学研究的深入和完善可使硫酸盐废水的处理水平和技术不断提高。

SRB法处理高浓度硫酸盐废水的试验研究

研究了在厌氧序批式反应器(ASBR)中,利用硫酸盐还原菌(SRB)处理含高浓度SO42-的酸性钛白粉废水的技术可行性及ASBR处理工艺的最佳运行参数。试验结果表明:SRB法处理含高浓度SO42-的酸性钛白粉废水是可行的,在选定试验条件下,模拟废水和钛白粉废水的SO42-去除率分别为92.7%和88.3%,且出水硫酸盐浓度在250mg·L-1以下,达到了国家地面水环境质量标准(GB3838-83)。

Interaction between sulfate-reducing bacteria and aluminum alloys——Corrosion mechanisms of 5052 and Al-Zn-In-Cd aluminum alloys

Microbiologically influenced corrosion caused by sulfate-reducing bacteria(SRB) poses a serious threat to marine engineering facilities.This study focused on the interaction between the corrosion behavior of two aluminum alloys and SRB metabolic activity.SRB growth curve and sulfate variation with and with aluminum were performed to find the effect of two aluminum alloys on SRB metabolic activity.Corrosion of 5052 aluminum alloy and Al-Zn-In-Cd aluminum alloy with and without SRB were performed.The results showed that both the presence of 5052 and Al-Zn-In-Cd aluminum alloy promoted SRB metabolic activity,with the Al-Zn-In-Cd aluminum alloy having a smaller promotion effect compared with 5052 aluminum alloy.The electrochemical results suggested that the corrosion of the Al-Zn-In-Cd aluminum alloy was accelerated substantially by SRB.Moreover,SRB led to the transformation of Al-Zn-In-Cd aluminum alloy corrosion product from Al(OH)3 to Al2 S3 and NaAlO2.

Lipid Evidence for Oil Depletion by Sulfate-Reducing Bacteria during U Mineralization in the Dongsheng Deposit

Fatty acids were extracted from fluid inclusions, and analyzed for distribution and individual 613C values to determine if there exists sulfate-reducing bacteria （SRB） and what substrates SRB depleted during U mineralization in the Dongsheng deposit. The 10-methylhexadecanoic acid （10Mel6：0） has been detected from most of the samples using GC-MS based on relative retention time and co-injection of standard 10Me16：0 compound. Samples with higher 10Me16： 0 concentrations, show higher U contents. The presence of 10Mel6：0 along with iso-ω7-cis-heptadecenoic acid （i17：1ω7c） and ω7-cisoctadecenoic acid （18：1ω7c） in the fluid inclusions may indicate the occurrence of SRB during the U mineralization. Saturated fatty-acids and unsaturated fatty-acids detected in this study have individual δ^13C values from-30.3‰ to-28.5‰ and-30.5‰ to-27.9‰, respectively. These values are close to those of n-alkanes of the associated oils and the bulk oils, but significantly distinct from methane, thus the oils are concluded to have been used as substrate for the microorganisms to survive on. This proposal is supported by oil biodegradation and ore-stage calcite cement with δ^13C values from-1.4‰ to-17.2‰.

The Microbial Metabolic Characteristics in the Course of Sulfate-Reduction

Acid-producing phase reactor of two-phase anaerobic treatment process has remarkable advantages treating sulfate-laden wastewater. In order to investigate SRB population's capability of utilizing substrate and the microbial acidification type formed during the course of sulfate reduction, continuous-flow and batch tests were conducted in a continuous stirred tank bio-film reactor supplied with sodium sulfate as electron acceptor. The experimental results demonstrated that the acidification type formed b...

材料微生物腐蚀的研究概况

综述了国内外近几十年来对铁、碳钢、不锈钢等一般金属材料,铝、铜、镍、钛及其合金等有色金属材料和部分工业非金属材料的微生物腐蚀的研究概况。指出了目前材料微生物腐蚀的途径、机理和控制方法。

Desulfovibrio sp.厌氧代谢淮南煤中>C12有机组分的实验研究

从淮南潘北煤矿采取530m深石炭系太原组石灰岩钻孔出水水样和二叠系山西组煤样,开展煤的有机成分与煤系地层地下水的SRB代谢关系实验。从水样中分离纯化出一菌株S890,经基因测序鉴定为脱硫弧菌Desulfovibrio sp.。煤样的甲醇萃取物经气质联用GC-MS仪检测,匹配出21种主要有机化合物,均为C11以上的高级链烃、环烃、芳香烃及其衍生物。选择其中3种有机化合物2,6-Di-tert-butyl-4-methylphenol、2-hexyl-1-Decanol和Naphthalene,2,6-dimethyl-做27d的SRB细菌厌氧培养与底物SO2-4含量与H2S、FeS产生量对比观测试验,发现SRB细菌可有效利用前2种碳源,而Naphthalene,2,6-dimethyl-未被利用。实验结果证实煤系地下水中的SRB生长可以有效地厌氧降解煤中一些较大分子有机化合物。

厌气混合培养中产甲烷菌和硫酸盐还原菌的动力学竞争 Ⅱ.动力学推定的结果及讨论

根据前文建立的动力学模型及批量实验结果,进行了包括乙酸及氢气利用在内的MPB和SRB的动力学常数的推定。结果显示,以Methanothrix及Methanobacter为种属的乙酸和氢气利用MPB;以Desulfobacter postageix和Desulfovibrior为种属的乙酸和氢气利用SRB分别存在于葡萄糖消化过程中。在反映现实情况的低浓度硫酸根离子条件下,热力学及动力学均占优势的乙酸利用SRB相反完全竞争不过乙酸利用MPB。这是由于对硫酸根离子乙酸利用SRB竞争不过氢气利用SRB的缘故,因为后者(Kg=10.7-13.3 mg/L)具有比前者(Ks=19.5-21.4mg/L)更高的硫酸根离子亲合性。这一结果进一步显示有必要重新评价长久以来一直承担负面角色的SRB的作用。因为如果从有利于厌气过程中甲烷主要产生者-乙酸利用MPB的生长这一角度来看,适量生长的氢气利用SRB能够完全抑止作为对手的乙酸利用SRB的生长以至发挥重大的正面作用。另外,该研究提供的动力学推定方法能简便、快速、准确的推定出微生物菌体浓度和诸动力学常数,对于生物处理的近乎所有过程都具有参考价值。

厌气混合培养中产甲烷菌和硫酸盐还原菌的动力学竞争 Ⅰ.动力学推定的模型及实验方法

产甲烷菌(MPB)和硫酸盐还原菌(SRB)的竞争是一个有关厌气处理过程生死存亡的重大问题。研究的目的是提供一个明确实际厌气过程中MPB和SRB竞争机理的动力学研究方法。首先,以Monod模型为基准建立了一整套动力学模型用于微生物菌体浓度和诸动力学常数推定。其次,进行包括乙酸和氢气利用MPB和SRB的两系列连续培养及批量实验,为下一步的动力学常数推定及讨论实际厌气过程中MPB和SRB的动力学竞争机理打好基础。

一个硫酸盐还原细菌富集物对丁草胺的厌氧降解

通过多次富集培养 ,得到一个能有效厌氧降解丁草胺的硫酸盐还原细菌 (SRB)富集物 ,并对该富集物的生长动力学以及生长的最适丁草胺浓度。

硫酸盐还原菌厌氧颗粒污泥的形成条件

硫酸盐还原菌是利用硫酸盐或其他氧化态硫化物作为电子受体来异化有机物的严格厌氧菌。介绍了硫酸盐还原菌的生物化学性质、代谢机理和生理学特征,综述了硫酸盐还原菌厌氧颗粒污泥的形成条件和影响因素,如进水SO2-4含量,碳源、氮源和磷源,COD与SO2-4质量浓度比,H2S,pH,温度,氧气及微量元素等。

高浓度硫酸盐废水的厌氧生物处理

对高浓度硫酸盐在废水的厌氧生物处理过程中的各种影响因素进行了综述,着重论述了硫酸盐还原菌的生态学特性,硫酸盐还原菌对产甲烷菌的抑制作用,以及各种高浓度硫酸盐废水的处理工艺。

硫酸盐在厌氧生物过程中的行为 Ⅰ.抑制作用及其影响因素

采用半连续实验方法,研究了中温条件下不同硫酸盐负荷在两种不同实验基质中对厌氧体系产生的影响和抑制作用规律.结果表明,在两种基质中硫酸盐对厌氧体系的抑制作用表现出相同的规律,在一定COD负荷下,SO_4^(2-)负荷小于0.10—0.30g/(L·d),对厌氧体系产生轻度抑制;SO_4^(2-)负荷大于1.5g/(L·d)时,会产生重度抑制作用.当COD/SO_4^(2-)≥7,体系中SO_4^(2-)累积浓度小于1000mg/L时,对厌氧体系基本不产生抑制作用;当COD/SO_4^(2-)≤1,体系中SO_4^(2-)累积浓度大于8000mg/L时,厌氧体系将受到严重抑制.实验结果还表明,适量硫酸盐及硫酸盐还原菌的存在有助于维持产酸菌及耗酸菌之间的平衡,防止体系出现酸化现象.