Electrogenic sulfur oxidation mediated by cable bacteria and its ecological effects

At the sediment-water interfaces,filamentous cable bacteria transport electrons from sulfide oxidation along their filaments towards oxygen or nitrate as electron acceptors.These multicellular bacteria belonging to the family Desulfobulbaceae thus form a biogeobattery that mediates redox processes between multiple elements.Cable bacteria were first reported in 2012.In the past years,cable bacteria have been found to be widely distributed across the globe.Their potential in shaping the surface water environments has been extensively studied but is not fully elucidated.In this review,the biogeochemical characteristics,conduction mechanisms,and geographical distribution of cable bacteria,as well as their ecological effects,are systematically reviewed and discussed.Novel insights for understanding and applying the role of cable bacteria in aquatic ecology are summarized.

Diverse transformations of sulfur in seabird-affected sediments revealed by microbial and stable isotope analyses

Microbial communities,sulfur isotope of sulfides(δ^(34)S_(AVS)and δ^(34)S_(CRS)),and sulfur and oxygen isotopes of sulfate(δ^(34)S_(SO_(4))and δ^(18)O_(SO_(4)))in sediments were analyzed to reveal the biogeochemical transformations of sulfur in a seabird-affected lake Y2 and a se abird-free YO from Fildes Peninsula,Antarctic Peninsula.The microbial communities in Y2 were mainly associated with penguin activities,while those in YO were limited by nutrients.The much enriched δ^(34)S_(SO_(4))recorded at depth of 30,41,and 52 cm in Y2indicates very strong sulfate reduction therein.The sulfur-degrading bacteria Pseudomonas in 0-23 cm of Y2 was 3.5 time s as abundant as that of sulfur oxidizing bacteria(SOB),indicating remarkable remineralization of organic sulfur.The abundant SOB and ^(34)S-depleted sulfate indicate considerable sulfur oxidation in 34-56-cm layer in Y2.In YO sediments,the highest abundance of Desulfotalea and the most enriched δ^(34)S_(SO_(4))(35.2‰)and δ^(34)S_(CRS)(2.5‰)indicate the strongest sulfate reduction in 28-cm layer.High abundance of Pseudomonas indicates active remineralization of organic sulfur in 3-5-cm layer in YO.The medium δ^(34)S_(SO_(4))and considerable abundance of SOB and sulfate-reducing bacteria(SRB)indicate concurrence of sulfur oxidation and sulfate reduction in other layers in YO.Therefore,a high level of organic matter input from penguin populations supported the diverse microbial community and transformations of sulfur in aquatic ecosystems in Antarctica.

净水污泥固定化硫氧化菌去除河道中AVS污染的试验研究

目的 研究净水污泥固定化硫氧化菌去除河道中的酸可挥发性硫化物污染方法,为净水污泥资源化利用提供一种新的思路。方法 通过高温焙烧的方法制备净水污泥固定化载体,采用XRD、SEM、BET对载体进行表征,使用净水污泥、绿沸石、活性炭3种载体对硫氧化菌进行固定化,分析其对底泥中AVS的去除效果以及固定化效果的影响,并通过高通量测序技术分析其对微生物种群变化的影响。结果 净水污泥固定化载体的最佳焙烧温度为600℃,无论是单一载体,还是固定化硫氧化菌,净水污泥组对于AVS的去除效果均要优于绿沸石和活性炭;同时硫氧化菌在温度为30℃、pH=6、固定化时间为24 h条件下的固定化效果最好;净水污泥固定化硫氧化菌的加入有利于降解硫化物优势菌种的群居,抑制了硫酸盐还原菌的生长繁殖。结论 净水污泥固定化硫氧化菌能有效去除河道中的AVS污染,降低底泥生物种群的多样性,有利于去除AVS优势菌种的群聚,抑制硫酸盐还原菌的繁殖,促进水体黑臭环境的改善。

砂浆粗糙度对污水硫氧化细菌生物被膜特征的影响研究

为分析粗糙度对硫氧化细菌生物被膜特征的影响,通过超景深显微镜、扫描电子显微镜、能谱仪、紫外分光光度计等表征方法,研究了污水环境中的硫氧化细菌在不同粗糙度砂浆试件表面形成生物被膜的宏观形貌、微观形貌、微生物数量、蛋白质含量及生物被膜厚度。结果表明:随着龄期的增加,试件粗糙度对硫氧化细菌生物被膜的宏观形貌、微观形貌及结构、生长脱落总周期影响不大,但会影响生物被膜的形成分布,粗糙度较大会延长生物被膜的黏附时间,并导致部分生物被膜提前脱落。

铅冶炼场地土壤微生物群落结构与硫氧化菌作用

长期的铅冶炼生产活动给周边地区带来了严重的重金属污染。重金属污染土壤的微生物群落结构和组成对其风险评估和污染修复具有重要意义。本文选择某铅冶炼区域的周边环境,研究重金属污染在垂直剖面上对土壤微生物群落结构和组成的影响。结果表明,重金属含量随着土壤垂直深度的增加而逐渐降低,中度污染土壤中微生物群落多样性高于低污染土;无论污染程度如何,表层土壤微生物群落多样性均高于底层;相对丰度优势属包括Perlucidibaca、Limnobacter、Delftia、Hydrogenophaga、Thiobacillus、Sulfurifustis、Sphingopyxis,其中硫氧化菌(SOB)丰度较高。XRD结果表明,土壤中存在PbSO_(4),可能是由于SOB的富集对硫的氧化作用。这种硫循环特征可能是铅(Pb)转化为PbSO_(4)的稳定化修复潜力。

Enrichment, isolation and identification of sulfur-oxidizing bacteria from sulfide removing bioreactor

Sulfur-oxidizing bacteria （SOB） are the main microorganisms that participate in the natural sulfur cycle. To obtain SOBwith high sulfur-oxidizing ability under aerobic or anaerobic conditions, aerobic and anaerobic enrichmentswere carried out. Denaturing gradient gel electrophoresis （DGGE） profiles showed that the microbial community changed according to the thiosulfate utilizationduring enrichments, and Rhodopseudomonas and Halothiobacilluswere the predominant bacteria in anaerobic enrichment and aerobic enrichment, respectively,which mainly contributed to the thiosulfate oxidization in the enrichments. Based on the enriched cultures, six isolateswere isolated from the aerobic enrichment and four isolateswere obtained from the anaerobic enrichment. Phylogenetic analysis suggested the 16S rRNA gene of isolates belonged to the genus Acinetobacter, Rhodopseudomonas, Pseudomonas, Halothiobacillus,0chrobactrum, Paracoccus, Thiobacillus, and Alcaligenes, respectively. The tests suggested isolates related to Halothiobacillus and Rhodopseudomonas had the highest thiosulfate oxidizing ability under aerobic or anaerobic conditions, respectively; Paracoccus and Alcaligenes could aerobically and anaerobically oxidize thiosulfate. Based on the DGGE and thiosulfate oxidizing ability analysis, Rhodopseudomonas and Halothiobacilluswere found to be the main SOB in the sulfide-removing reactor, andwere responsible for the sulfur-oxidizing in the treatment system.

Coupled trace element and SIMS sulfur isotope geochemistry of sedimentary pyrite:Implications on pyrite growth of Caixiashan Pb-Zn deposit

Colloform pyrite with core-rim texture is commonly deposited in carbonate platforms associated with the sulfide ores such as the Caixiashan Pb-Zn deposit.However,the genesis of colloform pyrite in Pb-Zn deposits,its growth controls and their geological implication are insufficiently understood.Integration of in-situ trace element and SIMS sulfur isotopes has revealed geochemical variations among these pyrite layers.These colloform pyrite occur as residual phases of core-rim aggregates,the cores are made up of very fine-grained anhedral pyrite particles,with some rims being made up of fine-grained and poorlycrystallized pyrite,while the other rims were featured with euhedral cubic pyrite.which are cemented by fine-grained calcite and/or dolomite with minor quartz.Sulfur isotope analysis shows that some wellpreserved rims have negative δ^34 S values(-28.12‰to-0.49‰),whereas most of the cores and rims have positive δ^34 S values(>0 to+44.28‰;peak at+14.91‰).Integrating with the methane and sulfate were observed in previous fluid inclusion study,we suggest that the 34 S depleted rims were initially formed by bacteria sulfate reduction(BSR),whereas the positive δ^34 S values were resulted from the sulfate reduction driven by anaerobic methane oxidation(AOM).The well-developed authigenic pyrite and calcite may also support the reaction of AOM.Combined with petrographic observations,trace element composition of the colloform pyrite reveals the incorporation and precipitation behavior of those high abundance elements in the pyrite:Pb and Zn were present as mineral inclusion and likely precipitated before Fe,as supported by the time-resolved Pb-Zn signal spikes in most of the analyzed pyrite grains.Other metals,such as Hg,Co and Ni,may have migrated as chloride complexes and entered the pyrite lattice.Arsenic and Sb,generally influenced by complex-forming reactions rather than substitution ones,could also enter the pyrite lattice,or slightly predate the precipitation of colloform pyrite as mineral inclusions,which are controlled by their hydrolysis constant in the ore fluids.The colloform pyrite may have grown inward from the rims.The successive BSR reaction process would enrich H^32/2S in the overlying water column but reduce the metal content,the nucleation of these pyrite rims was featured by strongly negative sulfur isotopes.The following AOM process should be activated by deformation like the turbidity sediment of the mudstone as the sulfide deposition are associated with fault activities that caused the emission of methane migration upward and simultaneously replenishing the metal in the column.The higher AOM reaction rate and the higher metal supply(not only Fe.but with minor other metals such as Pb and Zn) caused by sediment movement enhanced the metal concentration within the pyrite lattice.

Lipids of sulfate-reducing bacteria and sulfur-oxidizing bacteria found in the Dongsheng uranium deposit

U-bearing sandstones from the Dongsheng deposit in Ordos Basin contain abundant C15-C18 fatty acids. The fatty acids may have been derived from modern and ancient organisms including organisms from the intervals of U mineralization. A certain amount of i15:0, a15:0, a17:0 fatty acids coexist with small amounts of i17:1ω7c and 10me16:0, characteristic biomarkers of Desulfovibrio and Desulfobacter sp., respectively. This indicates the existence of sulfate-reducing bacteria (SRB) in the sandstones. The presence of sulfur-oxidizing bacteria (SOB), such as Beggiatoa and Thioploca, is indicated by significant amounts of 16:1ω7c and 18:1ω7c fatty acids. The existence of the SRB in the deposit, as inferred from the fatty acids, is consistent with results from fossilized microorganisms and isotopic compositions of ore-stage pyrite. This suggests that the environment may have been favorable for the SRB to grow since ore formation (9.8-22 Ma). The bacteria may have degraded hydrocarbons directly, or indirectly utilized hydrocarbons degraded by oxic microbes in the deposits. This process may have produced 12C-rich calcite and prominent baseline humps of unresolved complex mixtures (UCM), and 25-demethylated hopanes and tricyclic terpanes. The existence of sulfur-oxidizing bacteria and sulfate-reducing bacteria in the deposit may have resulted in bacterial sulfate reduction to sulfide, re-oxidization of the sulfide to sulfate and subsequent reduction of the sulfate to sulfide. This assertion is supported by ore-stage pyrite with δ34S values as low as-39.2‰, and the lightest sulfate (about 11‰) measured during the Phanerozoic, a difference of more than 46‰.

海水环境中硫氧化菌对混凝土性能的影响

目的 探究硫氧化细菌及其生物膜对混凝土宏观性能和微观结构的作用效果以明确硫氧化细菌对混凝土性能的影响规律。方法 将混凝土试样半浸泡于含有微生物的海水中,利用光学显微镜和紫外光密度(OD)分析不同龄期生物膜厚度、膜内微生物数量变化,观察测定混凝土不同龄期的外观形貌、抗压强度、质量以及通过电通量法分析混凝土抗氯离子渗透能力表征混凝土宏观性能,利用热分析仪、X射线衍射仪、压汞仪分析混凝土微观结构。结果 生物膜的生长、发育和脱落具有周期性规律,且膜内微生物数量与生物膜厚度呈正相关。120 d时无菌组混凝土电通量达到793.1 C,有菌组混凝土电通量仅为173.4 C,180 d时仅无菌对照组的混凝土出现开裂,240 d时有菌混凝土和无菌混凝土的质量损失率分别为0.79%、1.20%,有菌混凝土的抗压强度增加了6.9%,而无菌混凝土的抗压强度降低了7.1%;有菌组混凝土石膏生成量和C-S-H凝胶损失量均小于无菌混凝土,使得有菌组混凝土孔隙率比无菌组混凝土低了1.193 5%。结论 附着在混凝土的气液固界面的硫氧化细菌逐渐形成生物膜,膜厚度以及膜内微生物数量发生周期性变化,生物膜会降低SO42-的传质效率从而减缓混凝土的劣化。

西藏东北部热泉水中硫氧化菌的多样性及分布特征

热泉中存在大量的硫氧化菌,而西藏东北部丰富的热泉资源中硫氧化菌的相关研究较少。为探究西藏东北部热泉水中不同类型硫氧化菌(Sulfur-Oxidizing Bacteria,SOB)的多样性、群落结构及其分布特征,采集西藏东北部5个地热区总共13个热泉的地球化学及微生物样品,构建硫氧化基因dsrA和soxB的功能基因克隆文库、q PCR定量分析dsr A和soxB基因丰度,结合水化参数对比分析热泉水中dsrA型SOB和soxB型SOB的群落结构及其分布特征的差异。结果表明,西藏东北部热泉水中的硫氧化菌主要为β变形菌纲(Betaproteobacteria)、α变形菌纲(Alphaproteobacteria)、γ变形菌纲(Gammaproteobacteria)和嗜氢菌纲(Hydrogenophilalia),其中dsr A型SOB和soxB型SOB的优势类群在纲水平上均为Betaproteobacteria,但目水平上则存在差异,即soxB型SOB优势菌目为亚硝化单胞菌目(Nitrosomonadales)(30.0%-91.7%);dsr A型SOB优势菌目为红环菌目(Rhodocyclales)(33.3%-96.0%)。冗余分析(redundancy analysis,RDA)表明,SO_4^(2-)、S^(2-)、HCO_(3)~-、pH、温度等是影响硫氧化菌群落分布的关键环境因子。soxB基因相对丰度主要与SO_4^(2-)浓度、氧化还原电位(Oxidation-Reduction Potential,ORP)以及S^(2-)浓度相关,dsr A基因相对丰度受总砷(As~T)浓度和HCO_(3)~-浓度影响较大。这些结果表明,soxB基因型SOB主要分布于偏氧化环境,而dsr A基因型SOB主要分布于砷浓度、碱度相对偏高的热泉。该研究进一步完善了关于西藏热泉水环境中SOB多样性和分布规律的认识,促进了对热泉硫的生物地球化学循环的理解。

pH对生物脱硫系统的性能及菌群结构的影响

为探究pH对生物脱硫反应器性能、生物量及微生物种群结构的影响,一座生物滴滤池(bio-trickling filter,BTF)分别运行在中性偏碱(6.0<pH<9.5)、弱酸(2.6<pH<5.5)和极酸(pH<1.0)环境下。结果表明,BTF获得对H_(2)S的最大脱硫性能分别为246.5、142.8和164.6 g/(m^(3)·h)。中性偏碱下BTF的脱硫性能最佳,这是由于较低的H2 S气液传质阻力及较高的硫氧化菌活性。保持此pH范围需消耗大量碱性试剂,这导致反应器的运行成本升高和操作过程变得复杂。在极酸环境中,耐酸的硫氧化菌——Mycobacterium逐渐占据主导(79.2%),且生物膜拥有高硫氧化活性(比耗氧速率1.35 mg/(g·min)),非耐酸的微生物被淘汰,这维持了系统内生物量的稳定(生物量质量浓度10~11 g/L),避免了反应器的堵塞,降低了生物量控制和pH调整的成本。综上,通过富集高丰度且高活性嗜酸的Mycobacterium,BTF在极酸环境(pH<1.0)下仍可获得较高的脱硫性能,扩大了生物反应器运行的pH范围。

Sulfur dioxide and o-xylene co-treatment in biofilter：Performance, bacterial populations and bioaerosols emissions

Sulfur dioxide（SO_2） and benzene homologs are frequently present in the off-gas during the process of sewage sludge drying. A laboratory scale biofilter was set up to co-treat SO_2 and o-xylene in the present study. SO_2 and o-xylene could be removed simultaneously in a single biofilter. Their concentration ratio in the inlet stream influenced the removal efficiencies. It is worth noting that the removal of SO_2 could be enhanced when low concentrations of o-xylene were introduced into the biofilter. Pseudomonas sp., Paenibacillus sp., and Bacillus sp. were the main functional bacteria groups in the biofilter. Sulfur-oxidizing bacteria（SOB） and o-xylene-degrading bacteria（XB） thrived in the biofilter and their counts as well as their growth rate increased with the increase in amount of SO2 and o-xylene supplied. The microbial populations differed in counts and species due to the properties and components of the compounds being treated in the biofilter. The presence of mixed substrates enhanced the diversity of the microbial population. During the treatment process, bioaerosols including potentially pathogenic bacteria, e.g., Acinetobacter lwoffii and Aeromonas sp., were emitted from the biofilter. Further investigation is needed to focus on the potential hazards caused by the bioaerosols emitted from waste gas treatment bioreactors.

Hybrid zeolite-based ion-exchange and sulfur oxidizing denitrification for advanced slaughterhouse wastewater treatment

The discharge of slaughterhouse wastewater(SWW)is increasing and its wastewater has to be treated thoroughly to avoid the eutrophication.The hybrid zeolite-based ion-exchange and sulfur autotrophic denitrification(IX-AD)process was developed to advanced treat SWW after traditional secondary biological process.Compared with traditional sulfur oxidizing denitrification(SOD),this study found that IX-AD column showed:(1)stronger ability to resist NO_(3)^(-) pollution load,(2)lower SO_(4)^(2-) productivity,and(3)higher microbial diversity and richness.Liaoning zeolites addition guaranteed not only the standard discharge of NH_(4)^(+)-N,but also the denitrification performance and effluent TN.Especially,when the ahead secondary biological treatment process run at the ultra-high load,NO_(3)-N removal efficiency for IX-AD column was still~100%,whereas only 64.2%for control SOD column.The corresponding average effluent TN concentrations for IX-AD and SOD columns were 5.89 and 65.55 mg/L,respectively.Therefore,IX-AD is a promising technology for advanced SWW treatment and should be widely researched and popularized.

海岸盐沼湿地土壤硫循环中的微生物及其作用

硫及硫化合物的动态循环是海岸盐沼湿地的重要组成部分,硫酸盐还原菌(SRB)和硫氧化菌(SOB)是推动硫循环的重要微生物。硫酸盐还原菌把硫酸盐还原为硫化物,同时消耗土壤中的有机物质;硫氧化菌把还原性硫化合物氧化为硫酸盐,缓解土壤中硫化物的积累,它们共同维持硫循环的动态平衡。本文综述了海岸盐沼湿地土壤中硫的存在形式、硫的地球化学循环以及在硫循环过程中扮演重要角色的硫酸盐还原菌和硫氧化菌的生物多样性、活性测定方法及其生态学意义等的最新研究进展,并提出了存在的问题及研究展望。

嗜酸硫氧化细菌作用下元素硫化学形态的研究进展

嗜酸硫氧化细菌是生物冶金过程中研究最为广泛的细菌,广泛分布在含硫和硫化物丰富的环境中。嗜酸硫氧化细菌作用下,单质硫及其它还原型硫化物(包括金属硫化矿)经过一系列形态转换使得硫在其细胞体内、体外和环境沉积物中存在着不同形态分布。单质硫经细菌细胞活化后在细胞体内以硫球形式积累;还原型硫化物可被细菌氧化至硫酸盐,其氧化中间态多为单质硫或连多硫酸盐等。有关嗜酸硫氧化细菌作用下硫的形态研究十分缺乏,进一步开展嗜酸硫氧化细菌作用下元素硫化学形态的研究可以为这类细菌的硫氧化机制及对硫化矿的浸出机理的阐明提供理论依据。

不同接种量下生物沥滤去除污泥中重金属的研究

采用污泥的硫细菌混合菌液以2%、5%、10%和20%的接种量,序批试验研究了污泥中重金属的生物沥滤.结果表明,沥滤初期污泥pH的下降幅度和速率随混合菌液接种量增大而增大,而第4日后,4种接种量的污泥样品pH相差不大,最终稳定在1.4左右;污泥中硫细菌对硫的利用,使SO42-浓度迅速上升,同时也有少量的重金属硫化物被硫细菌利用.硫细菌接种液可明显促进污泥中Cu、Pb和Zn的沥滤,缩短沥滤周期;接种量越大,沥滤启动越快,Zn的沥滤启动快于Cu和Pb.达到最高沥滤效率后,Cu和Zn的沥滤效果均较为稳定,而Pb则有明显的持续降低趋势.选用2%硫细菌混合菌液接种量,沥滤时间控制在5～6d,Cu、Pb和Zn的沥滤效果可达到最佳,沥出率分别为96.5%、41.4%和82.9%.

利用硫氧化细菌改良盐碱土

硫氧化细菌具有氧化单质硫及硫化物,生成硫酸的特性。根据硫氧化细菌的这种生物特性,使其在盐碱土中发生生化反应,将硫磺粉氧化生成硫酸,中和盐碱土中的OH-,从而达到改良盐碱土的目的。在实验中,土样分为吹填土、盐田土、农田土、绿化土4组,将一定体积的氧化硫硫杆菌、排硫杆菌菌液和硫磺粉加入到各土样中,每12 h观测一次土壤上清液的pH值和电导率。实验结果表明:氧化硫硫杆菌和排硫杆菌对降低土壤pH值有明显作用,使土壤pH值由7.5降低到7.2,对改良碱土有一定的作用。

我国主要低产水稻冷浸田土壤微生物特征分析

研究我国冷浸田主要分布的7个省份冷浸田土壤样品的微生物特征,通过与当地高产田土壤微生物特征比较发现:我国冷浸田土壤的微生物量碳含量(70.98～356.61mg/kg)总体低于高产田,差异显著(P<0.05);冷浸田土壤中可培养的细菌、真菌、放线菌、氨化细菌、固氮菌、纤维素分解菌的平均值分别为高产田土壤的53.93%,43.33%,47.32%,51.98%,44.83%,47.80%。表明我国冷浸田土壤微生物总量偏低且活性弱。但是,可培养的硫化细菌数量(平均16.21×106个/g土)和铁还原菌数量(平均9.28×107个/g土)高于高产田土壤中可培养的硫化细菌数量(平均13×106个/g土)和铁还原菌的数量(平均7.32×107个/g土),说明我国冷浸田土壤中硫化氢和亚铁浓度较高。因此,只要有针对性的改良冷浸田土壤微生物群落结构和功能的多样性,冷浸田土壤肥力将大大提高。

低电位生物浸出黄铜矿研究

在酸性溶液中,高浓度Fe2+离子的存在有助于溶解氧对黄铜矿的氧化浸出。试验驯化培养具有单一硫氧化性的高效浸矿细菌,运用其对单体硫的高效氧化性能,结合Fe2+离子对黄铜矿氧化浸出的促进作用,开展黄铜矿低电位生物浸出研究。研究发现硫氧化菌可有效利用黄铜矿氧化溶解的产物——单体硫,将其氧化为硫酸并补充溶液H+离子消耗。同时,清除黄铜矿表面氧化溶解产物——单体硫后,有助于离子扩散和黄铜矿的进一步氧化溶解。

生物沥浸法去除畜禽粪便中重金属的影响因素研究

研究了粪液固体浓度和硫细菌混合菌液接种量对猪粪中重金属生物沥浸的影响。结果表明，猪粪固体浓度越低，重金属沥浸周期越短，沥浸效果越好。从沥浸效果和经济效益2方面综合考虑，固体质量浓度采用70～100g·L^-1较为合适。接种量也是影响生物沥浸的重要因素，试验结果表明，接种量越大，生物沥浸速度越快，但接种量小的粪样只需适当延长沥浸时间即可达到较高的重金属去除效果，2％接种量的猪粪沥浸14d时，Cu、Zn和Cd沥出率可分别达到76．9％、75．2％和47．8％。从经济角度考虑，接种量采用2％即可满足生物沥浸的需要。