脱氮硫杆菌生长特性及其对SRB生长的影响

由土壤中分离得到一株自养型的脱氮硫杆菌(Thiobacillus denitrigioans,硫杆菌属,硫杆菌科,革兰氏阴性化能自养细菌),该菌株的最佳生长pH为7．0。将此菌株与硫酸盐还原菌(Sulfate Reducing Bacteria,SRB,脱硫弧菌属,革兰氏阴性厌氧细菌)混合培养,测定SRB的菌量变化,结果表明,脱氮硫杆菌的生长抑制了硫酸盐还原菌的生长,降低了SRB的腐蚀性的代谢产物硫化物的浓度,腐蚀速率降低,有利于防治SRB引起的微生物腐蚀。     

脱氮硫杆菌生长特性及其对SRB生长的影响*

由土壤中分离得到一株自养型的脱氮硫杆菌 (Thiobacillusdenitrificans,硫杆菌属 ,硫杆菌科 ,革兰氏阴性化能自养细菌 ) ,该菌株的最佳生长 pH为 7 0。将此菌株与硫酸盐还原菌 (SulfateReducingBacteria ,SRB ,脱硫弧菌属 ,革兰氏阴性厌氧细菌 )混合培养 ,测定SRB的菌量变化 ,结果表明 ,脱氮硫杆菌的生长抑制了硫酸盐还原菌的生长 ,降低了SRB的腐蚀性的代谢产物硫化物的浓度 ,腐蚀速率降低 ,有利于防治SRB引起的微生物腐蚀。     

一株脱氮硫杆菌的筛选及其脱氮除硫性能分析

利用人工模拟酸性环境,从定期浇注HCl的土壤中筛选出一株脱氮硫杆菌T1菌株,并对其生长特性以及pH、盐度等理化因素对其脱氮除硫性能的影响进行了研究。结果表明,该菌株最适生长pH为7.02,最适脱氮pH为7.0;培养基中NaCl含量低于1.5%时,其脱氮能力没明显变化;与硫酸盐还原菌混菌培养能将H2S氧化为SO42-,从而明显抑制H2S的产生。在液体静置混菌培养过程中,在培养开始后的24 h内,SO42-生成速率最大(11.21 mg/(L·h)),随后不断降低。该菌不仅适用于不同pH、盐度废水的生物处理,还可以与硫酸盐还原菌混合添加到厌氧消化池中以减少硫化物的形成,从而减轻后者对污水处理系统中的金属设备和管道的腐蚀作用以及硫化氢对大气的污染。     

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。     

锅炉管道回水、厌氧污泥中硫酸盐还原菌的筛选

目的研究硫酸盐还原菌及其筛选、分离鉴定体系.方法在锅炉管道回水和厌氧污泥中驯化、筛选硫酸盐还原能力强的菌株,以铬酸钡光度方法检测液体培养基中的硫酸根含量,测定了菌株的硫酸盐降解能力.结果在水样A和泥样B中,A1和B2菌株能够较好地降解培养基中的硫酸盐,通过计数得出A1和B2的最大可能菌数分别为1.65×10(6)个/ml、2.25×10(6)个/ml.并利用改进的稀释涂布-叠皿夹层培养方法分离鉴定A1和B2菌株,观察硫酸盐还原菌的形态,为进一步了解SRB的生长特性,进而从根本上解决硫酸盐还原菌腐蚀问题提供理论基础.结论经过实验,所筛选分离鉴定体系可行.     

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。     

脱氮硫杆菌硫化合物载体SoxYZ蛋白的同源建模和结构分析

脱氮硫杆菌(Thiobacillus denitrificans)中的Sox蛋白在硫代谢过程中起着至关重要的作用,硫化合物需先与硫氧化基因族(sox)编码的蛋白质Sox YZ二聚体共价连接后才能与其他酶发生相互作用。利用同源建模法构建硫化合物载体Sox YZ蛋白的二聚体结构并验证了其合理性。二聚体相互作用分析发现Sox YZ蛋白的溶剂可及表面积(solvent accessible surface,SAS)为10 922.92,疏水率为50.85%;亚基Sox Y和Sox Z界面处共含有12个氢键和1个Π键来维持其三维结构的稳定性;二聚体表面呈现明显的正负电势互补,两亚基界面处氨基酸残基的VDW作用能和静电作用能分别为-80.925 13kcal/mol和-323.856 57kcal/mol,这说明静电作用是二聚体形成的主要驱动力;Sox Z亚基的残基Thr28、Arg31、Lys32、Ser64、Gly65、Val66、Ser67对Sox Y亚基活性位点构象的稳定有重要作用。     

PCR-SSCP技术分析碱度影响下硫酸盐还原反应器中微生物群落动态

采用PCR-单链构象多态性(SSCP)技术和杂交技术, 分析进水碱度降低引起的产酸-硫酸盐还原反应器中微生物群落动态. 试验结果表明, 碱度人为控制在4000 mg/L, 硫酸盐负荷率为4.8 kg/(m³·d)时, 反应器25天启动成功, 硫酸盐去除率达87%, 此时Lactococcus sp., Anaerofilum sp.和Kluyvera sp.等占优势. 当短时间降低进水碱度至1000 mg/L以下时, 硫酸盐去除率迅速降到35%; 继而提高并稳定进水碱度为3000 mg/L时, 硫酸盐去除率稳定在55%, Dysgonomonas sp., Sporobacte sp., Obesumbacterium sp.和Clostridium sp.得以富集, 同Lactococcus sp., Anaerofilum sp.和Kluyvera sp.一起构成优势菌群. 碱度继续降低并稳定至1500 mg/L时, 硫酸盐的去除率上升并稳定在70%, Dysgonomonas sp., Sporobacter sp.和Obesumbacterium sp.消亡, 而Desulfovibrio sp.和Clostridium sp.的某些菌种得以大量富集. 为探讨系统所能承受的最低碱度阈值, 再次将碱度降低至400 mg/L, 发现硫酸盐去除率、pH值和出水碱度迅速下降, Petrotoga sp., Prevotella sp., Kluyvera sp.和Neisseria sp.的数量水平明显降低, 杂交显示硫酸盐还原菌(SRB)的数量也随之降低. 微生物群落结构特征和多样性分析表明, 种泥中的SRB种群异常丰富, 碱度降低使种群的丰度逐渐趋于单一. 常驻种群绝大多数为发酵产酸菌(FAB), 其中Firmicute门所占的比例最大, 而SRB所占数量比例极少. 这种群落结构体现了FAB与SRB之间的协同代谢作用, 从而维持着系统硫酸盐较高去除率和运行稳定性.     

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。     

脱氮硫杆菌特异引物/探针的设计和评价

自脱氮硫杆菌(Thiobacillus denitrificans)16S rRNA基因V3可变区中发现一条27 bp的特异序列, 以该序列为反向引物, 对高效同步脱硫反硝化系统污泥DNA进行了温度梯度PCR扩增和基因文库构建, 结果证实了该引物的高度专一性。应用该探针在去离子甲酰胺和NaCl的浓度分别为35%和100 mmol/L, 杂交/洗脱温度为48°C条件下对污泥样品杂交得到较好的阳性结果, 软件分析表明脱氮硫杆菌在污泥中约占15%。脱氮硫杆菌专一性引物/探针的提出, 将为不同生态环境中该种微生物的时空分布、结构动态以及实时定量等研究提供分子生物学工具。     

Sulfur metabolism in Thiobacillus denitrificans

The relatively high specific sulfite reductase activity of 25 mU/mg protein was found in extracts from Thiobacillus denitrificans. The absorption spectrum of the partially purified enzyme was similar to the siroheme containing sulfite reductases from other sources. It is suggested that the T. denitrificans sulfite reductase may function during the oxidation of reduced sulfur compounds.     

Cell yield and bioenergetics of Thiomicrospira denitrificans compared with Thiobacillus denitrificans

From cell yields of Thiomicrospira denitrificans grown in the chemostat at different growth rates under anaerobic conditions a value of 1.4mm S₂O _inf3 ^sup= per g dry wt and per h could be calculated for maintenance energy requirements, and of 5.65 g dry wt per mole S₂O _inf3 ^sup= for the true growth yield.Cell yields of Thiomicrospira denitrificans appeared to be almost half of those of Thiobacillus denitrificans. Though in Thiobacillus denitrificans at D=0.03 h^-1 under anaerobic conditions a value was found of 11.60 g dry wt per mole of thiosulphate used for energetic purposes, a value of 5.72 g dry wt per mole of thiosulphate was found under comparable conditions in Thiomicrospira denitrificans. Under aerobic conditions at D=0.03 h^-1 values of 18.54 g dry wt per mole of thiosulphate were found in Thiobacillus denitrificans whereas Thiomicrospira denitrificans yielded only 9.38 g dry wt per mole of thiosulphate.As in Thiobacillus denitrificans anaerobic cell yields on sulphide were comparable to those on thiosulphate.Calculations have been made which indicate that the biosynthetic efficiency of Thiomicrospira denitrificans is lower than that of Thiobacillus denitrificans. This can only partly be explained by the absence of adenosine-phosphosulphate (APS) reductase.     

Thermotolerance of adenylylsulfate reductase from Thiobacillus denitrificans

Abstract Adenylylsulfate (APS) and APS reductase are important in the energy-generating processes of sulfate-reducing bacteria and sulfur lithotrophs (phototrophs and nonphototrophs). APS reductase from an extremely thermophilic archaebacterial sulfate-reducer was recently shown to be thermophilic with optimal activity at 85°C (Speich and Truper (1988) J. Gen. Microbiol. 134, 1419–1425). APS reductase of Thiobacillus denitrificans , a mesophilic eubacterium, has biochemical and physical properties in common with the thermophilic enzyme and is also thermotolerant (up to 75°C). APS reductase and other enzymes of dissimilative inorganic sulfur metabolism may commonly be thermotolerant is mesophilic eubacteria; perhaps a vestige of their primordial significance.     

Intermediates of denitrification in the chemoautotroph Thiobacillus denitrificans

Summary Intact cells obtained from Thiobacillus denitrificans grown autotrophically with thiosulfate as the oxidizable substrate and nitrate as the final electron acceptor catalyzed the reduction of nitrate, nitrite and nitric oxide stoichiometrically to nitrogen gas with the concomitant oxidation of thiosulfate. In addition, nitrous oxide was also capable of acting as the terminal oxidant of the respiratory chain with thiosulfate as the reductant. The anaerobic oxidation of thiosulfate by NO₃ ^-, NO, and N₂O was sensitive to the flavoprotein inhibitors, antimycin A or NHQNO, and cyanide or azide thus, implicating the participation of flavins, and cytochromes of b-, c-, and a-types in the denitrification process. The nitrite reductase system, however, was not markedly affected by the electron transport chain inhibitors. The experimental observations suggest that the dissimilatory nitrate reduction in the chemoautotroph T. denitrificans involves nitrite, nitric oxide, and nitrous oxide as theintermediates with nitrogen gas as the final reduction product.Non-Standard Abbreviations TTFA Thenoyltrifluoroacetone - NHQNO 2-n-nonyl-4-hydroxyquinoline N-oxide     

Aerobic oxidation of hydrogen sulfide by Thiobacillus denitrificans

It has been demonstrated that Thiobacillus denitrificans may be readily cultured aerobically in batch and continuous flow reactors on H(2)S(g) under sulfide limiting conditions. Under these conditions sulfide concentrations in the culture medium were less than 1muM resulting in very low concentrations of H(2)S in the reactor outlet gas. Biomass yield under aerobic conditions was much lower than previously reported for anaerobic conditions, presumably because of oxygen inhibition of growth. However, biomass yield was not affected by steady state oxygen concentration in the range of 45muM-150muM. Biomass yield was also observed to be essentially independent of specific growth rate in the range of 0.030-0.053 h(-1). Indicators of reactor upset were determined and recovery from upset conditions demonstrated. Maximum loading of the biomass for H(2)S oxidation under aerobic conditions was observed to be 15.1-20.9 mmol/h/g biomass which is much higher than previously reported for aerobic conditions. Other aspects of the stoichiometry of aerobic H(2)S oxidation are also reported.     

Proton translocation in intact cells of Thiobacillus denitrificans

Proton translocation assessed by the quinacrine fluorescence technique was compared with oxygen uptake during thiosulphate oxidation by cells of Thiobacillus denitrificans. The addition of thiosulphate to cell suspensions resulted in an outwardly directed proton translocation as reflected by an increased quinacrine fluorescence. Compared to the O₂ uptake activity, the proton translocating system was much more sensitive to proton conductors, other ionophores and inhibitors of electron transport. The results indicate that (a) the proton-translocation activity (membrane energization) is enhanced in aged cell suspensions, (b) intactness of the cytoplasmic membrane is essential for establishing a protonmotive force in cells, (c) the fluorescence increase and proton translocation are reversible processes, (d) inhibitors of electron transport may also act as proton conductors by altering the integrity of the cytoplasmic membrane.Abbreviations CCCP carbonyl cyanide m-chlorophenyl-hydrazone - DBP 2,4-dibromophenol - DNP 2,4-dinitrophenol - HOQNO 2-heptyl-4-hydroxyquinoline-N-oxide - PCP pentachlorophenol - TPB tetraphenyl boron - TTFA 1-[thenoyl-(2)]-3,3,3-trifluoracetone     

Assessment of the addition of Thiobacillus denitrificans and Thiomicrospira denitrificans to chemolithoautotrophic denitrifying bioreactors

The aim of the present study was to assess the impact of adding cultures of Thiobacillus denitrificans and Thiomicrospira denitrificans to two upflow anaerobic sludge bed (UASB) reactors: one inoculated with granular sludge and the other filled only with activated carbon (AC). The performances of the bioreactors and the changes in biomass were compared with a non-bioaugmented control UASB reactor inoculated with granular sludge. The reactors inoculated with granular sludge achieved efficiencies close to 90% in nitrate and thiosulfate removal for loading rates as high as 107 mmol-NO3 -/l per day and 68 mmol-S2O3 2-/l per day. Bioaugmentation with Tb. denitrificans and Tm. denitrificans did not enhance the efficiency compared to that achieved with non-bioaugmented granular sludge. The loading rates and efficiencies were 30-40% lower in the AC reactor. In all the reactors tested, Tb. denitrificans became the predominant species. The results strongly suggest that this bacterium was responsible for denitrification and sulfoxidation within the reactors. We additionally observed that granules partially lost their integrity during operation under chemolithoautotrophic conditions, suggesting limitations for long-term operation if bioaugmentation is applied in practice.