Effect of hydrogen sulfide on growth of sulfate reducing bacteria

A culture of sulfate reducing bacteria (SRB) growing on lactate and sulfate was incubated at different pH values in the range of 5.8-7.0. The effect of pH on growth rate was determined in this pH range; the highest growth rate was observed at pH 6.7. Hydrogen sulfide produced from sulfate reduction was found to have a direct and reversible toxicity effect on the SRB. A hydrogen sulfide Concentration of 547 mg/L (16.1 mM) completely inhibited the culture growth. Comparison between acetic acid and hydrogen sulfide inhibition is presented and the concomitant inhibition kinetics are mathematically described. (c) 1992 John Wiley & Sons, Inc.     

2株海绵细菌的分离与鉴定

利用R2A培养基对海绵中的细菌进行分离,获得89株菌落形态有差异的菌株。通过在R2A培养基和营养丰富的LB培养基上的长势比较,发现有13株菌在LB培养基上生长缓慢、长势较弱。对此13株菌进行16S rDNA序列测定,发现菌株HB09009与Bacillus carboniphilus JCM9731T(AB021182)同源性最高,为97.1%;菌株HB09012与Planctomyces maris DSM8797T(NR025327)同源性最高,为97.4%,在发育树上处于一个分支,但在生长条件、培养特征和生理生化等方面都存在较大的差异,初步鉴定HB09009可能是Bacillus属的一个新种,暂定名为Bacillus sp.HB09009;鉴定HB09012可能是Planctomyces属的一个新种,暂定名Plancto-myces sp.HB09012。     

2株瘤胃纤维降解细菌的分离鉴定

从日粮精粗比为3:7的小尾寒羊×蒙古羊杂交一代绵羊的瘤胃内容物中分离到2株严格厌氧细菌,一株球菌WQ-1,1株弧菌WH-2,二者对滤纸有很好的降解能力。通过酶活力试验测得WQ-1的滤纸酶活、羧甲基纤维素酶活和β-葡萄糖苷酶活分别为0.66,7.0 U/mL和15.3 U/mL;WH-2的滤纸酶活、羧甲基纤维素酶活和β-葡萄糖苷酶活分别为0.52,6.9 U/mL和17.2 U/mL。经形态学、生理生化反应、生态特性和遗传型的鉴定,WQ-1归类为瘤胃球菌属(Ruminococcus)的黄色瘤胃球菌(Ruminococcus flavefaciens)。WH-2归类为丁酸弧菌属(Butyrivibrio)的溶纤维丁酸弧菌(Butyrivibrio fibrisolvens)。     

Upgrading the efficiency of dissimilatory sulfate reduction by Desulfovibrio desulfuricans via adjustment of the COD/SO4 ratio

The potential for upgrading the microbiological reduction of sulfates and for decreasing the organic pollution levels in industrial waste-water by the adjustment of the COD/SO4 ratio was investigated. The experiments involved waste-water samples coming from industrial pig farming, baker's yeast production and organic dye manufacture. The results show that in the presence of Desulfovibrio desulfuricans both the objectives can be achieved by abating the disproportion between the content of sulfates and that of organic substances.     

Streptomyces sp. strain isolated from river water has high bisphenol A degradability

AIMS: We report the identification of the bisphenol A (BPA) biodegradability in Streptomyces sp. strain isolated from river water. METHODS AND RESULTS: The water samples spiked with BPA (1 mg l(-1)) and the culture solution of Streptomyces sp. strain were placed at 30 degrees C for 10 days and were analysed by high-performance liquid chromatography. A half-life for BPA degradation was between 3 and 4 days. The removal rate of BPA was >90% for 10 days. CONCLUSIONS: These results show that the Streptomyces sp. strain isolated from river water has high BPA degradability. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, this is the first report of BPA degradation by Streptomyces sp. strain.     

甲醇降解菌的分离及性质研究

对氮肥厂活污泥进行驯化筛选得到3株甲醇降解菌,可耐10,000mg/L左右的甲醇浓度,实验得出其最佳生长条件为：pH7-8、温度30℃－35℃、通气,在适宜条件下,对甲醇有较好的降解能力。     

Isolation from coastal sea water and characterization of bacterial strains involved in non-ionic surfactant degradation

A bacterial community degrading branched alkylphenol ethoxylate (APE) was selected from coastal sea water intermittently polluted by urban sewage. This community degraded more than 99% of a standard surfactant, TRITON X 100, but I.R. analysis of the remaining compound showed the accumulation of APE₂ (alkylphenol with a two units length ethoxylated chain) which seemed very recalcitrant to further biodegradation. Twenty-five strains were isolated from this community, essentially Gram negative and were related to Pseudomonas, Oceanospirillum or Deleya genera. Among these strains, only four were able to degrade APE_9–10 (TRITON X 100). They were related to the Pseudomonas genus and were of marine origin. Pure cultures performed with these strains on TRITON X 100 gave APE₅ and APE₄ as end products. These products were further degraded to APE2 by two other strains unable to degrade the initial surfactant.     

Efficient method to isolate and purify viruses of bacteria from marine environments

Aim:  To isolate viruses of specific heterotrophic bacterial strains from marine environments using a host addition/virus amplification protocol (HAVAP) for use in phage/host systems.
Methods and Results:  Bacteria-free seawater samples containing natural viruses assemblages were inoculated with a single laboratory grown bacterial host of interest in a nutrient-enriched [peptone, Fe(III) and yeast extract] seawater suspension. These conditions enhanced the replication of only those virus(s) capable of infecting the host bacterium. After incubation, free viruses were recovered at concentrations ranging 10⁵–10¹⁰ infectious virus particles per ml of seawater. Using this approach, 15 viruses were isolated and represented 12 unique phage/host systems. Two of the hosts tested were infected by more than one virus.
Conclusions:  Isolation of high concentrations of specific viruses is possible even if their initial concentrations in native waters are low. This approach allows the recovery of phage/host systems that may not be numerically dominant.
Significance and Impact of the Study:  This host enrichment protocol for virus detection and isolation is well-suited for aquatic viral ecology studies that require phage/host systems.     

Analysis of interactions between potent inhibitors of ATP sulfurylase via molecular dynamics

The dynamic behaviour of adenosine triphosphate sulfurylase (ATPs) is analysed to investigate its energetic interactions with inhibitors recently studied theoretically and tested experimentally. The interactions between ATPs and three inhibitors namely, 2,2′-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS), butylated hydroxytoluene (BHT), and 3-tert-butyl-4-hydroxyanisole (BHA) in aqueous solution were studied via molecular dynamics simulations. The results of the absolute and relative free energies reveal the existence of synergism in the system. Additionally, the system demonstrates strong steric effect between ABTS and BHA that is not only due to the size of these inhibitors but also their surroundings.     

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。     

柴油降解细菌的分离及其降解能力初探

从含油土壤中,筛选出能以0#柴油为惟一碳源的2株柴油降解菌,经鉴定分别为假单胞菌(Pseudomonoussp.)和芽孢杆菌(Bacillussp.)。通过其降解能力的测试,假单胞杆菌属细菌A8的降解能力较强;在含油浓度ρ=10g/L的摇瓶试验中,培养7d后其除油率分别为18%和31%。在含油浓度1%的土壤中,2株菌均能正常生长和繁殖,接种30d除油率分别为35%和48.3%。     

一种从感染的培养细胞中分离细菌RNA的方法

病原菌全基因组表达谱研究是阐明其致病机理的必要的基础 ,已经成为当前生命科学领域的热点和重点 ;然而由于难于从感染的组织中快速固定并分离细菌RNA ,从而极大的制约了该研究的进展。介绍一种从感染的细胞中分离细菌RNA的方法———冷酸酚法 ,其主要特点是 :(1)使用可以破碎真核细胞但不影响细菌细胞完整性的SDS浓度 ,实现了从感染的细胞中快速分离完整的细菌 ,减少了宿主细胞RNA的污染 ;(2 )在将细菌从细胞中分离的同时即利用苯酚 乙醇混合液将其总RNA快速固定 ,既减少了RNA的降解 ,又最大限度地保持了细菌在哺乳细胞内原有的表达模式 ;(3)可以从 10 8个菌体中提取到至少 30 μg的总RNA ,足够用于反转录等其他研究。该方法将为利用DNAMicroarray技术进行的病原菌表达谱研究提供有益的借鉴。     

Enhanced sulfate reduction and trichloroethylene (TCE) biodegradation in a UASB reactor operated with a sludge developed from hydrothermal vents sediments: Process and microbial ecology

Most Trichloroethylene (TCE) biodegradation reports refer to methanogenic conditions, however, in this work, enhanced sulfidogenesis and TCE biodegradation were achieved in an upflow anaerobic sludge blanket (UASB) reactor in which a completely sulfidogenic sludge, from hydrothermal vents sediments, was developed. The work was divided in three stages, (i) sludge development and sulfate reducing activity (SRA) evaluation, (ii) TCE biodegradation and (iii) SRA evaluation after TCE biodegradation. For (i) SR was 98 ± 0.1%, 84% as sulfide (H₂S, 1200 ± 28 mg/L), sulfate reducing activity (SRA) was 188 ± 50 mg COD H₂S/g VSS*d. For (ii) The reactor reached 74% of TCE removal, concentrations of vinyl chloride of 16 ± 0.3 μM (5% of the TCE added) and ethene 202 ± 81 μM (67% of the TCE added), SRA of 161 ± 7 mg COD H₂S/g VSS*d, 68% of sulfide (H₂S) production and 93% of COD removal. For (iii) SRA was of 248 ± 22 mg COD H₂S/g VSS*d demonstrating no adverse effects due to TCE.Among the genera of the microorganisms identified in the sludge during TCE biodegradation were: Dehalobacter, Desulfotomaculum, Sulfospirillum, Desulfitobacterium, Desulfovibrio and Clostridium. To the best of our knowledge, this is the first report using a sulfidogenic UASB reactor to biodegrade TCE. The overall conclusions of this work are that the reactor is efficient on both, sulfate and TCE biodegradation and it could be used to decontaminate wastewater containing organic solvents and relatively high concentrations of sulfate.     

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。     

山西阳泉老窑水硫酸盐还原菌的分离鉴定及其还原功能驯化

【背景】含硫煤矿开采后,地表水/地下水回流至采空区形成酸性老窑水,含有高浓度重金属离子和硫酸盐,严重危害生态系统健康。利用微生物自身生长处理老窑水具有成本低、环境友好等特点,具有良好的应用前景。目前利用的硫酸盐还原菌大多只在适宜温度和中性pH条件下具有较高活性,在北方低温和酸性条件下难以发挥作用。【目的】本研究旨在从山西阳泉山底河流域的老窑水环境中分离硫酸盐还原菌,并调节温度和pH进行驯化,从而得到高效耐低温耐酸菌株,为北方老窑水微生物治理提供可用菌种资源。【方法】对山底河流域典型老窑水样品中的微生物进行富集培养,并筛选硫酸盐还原菌。通过革兰氏染色、扫描电镜对菌株形貌特性进行表征,利用16SrRNA基因序列比对进行菌种鉴定,探究其生长特性和硫酸盐还原性能。在此基础上降低温度和pH,对高效还原硫酸盐菌株进行驯化,探讨其在北方老窑水污染治理中的应用潜力。【结果】本研究筛选得到2株硫酸盐还原菌,命名为YQ-1和YQ-2,分别属于革兰氏阴性瘤胃解蛋白质菌属(Proteiniclasticum)和脱硫弧菌属(Desulfovibrio)。在30°C、pH 7.5条件下,YQ-1和YQ-2对1 1...     

Isolation and identification of bacterial strains with insecticidal activities from Rhynchophorus ferrugineus Oliver (Coleoptera: Curculionidae)

Several pathogenic bacteria strains were isolated from dead larvae of the weevil, Rhynchophorus ferrugineus Oliver, collected on palm trees in Taiwan, China. Strains of pure cultures were temporarily named TW‐1, TW‐2, TW‐3, TW‐4, TW‐5, TW‐6, TW‐7, TW‐8, TW‐9, TW‐10, TW‐11, TW‐12, TW‐13 and TW‐14. These strains were identified by synthetically using colony morphological characters, physiological and biochemical tests and molecular biological analysis. Our results showed that these 14 isolated strains belonged to four genera and five species. The expected approximate 1400‐bp bands were obtained through 16S rDNA universal primer amplification. The sequencing results obtained from a commercial sequencing company were initially compared with a corresponding database from NCBI using BLAST, and a phylogenetic tree was constructed using mega 5.1 software. The phylogenetic results indicated that these isolated strains had more than 99% homology with type strains. To further confirm these strains, numerous physiological and biochemical indexes were confirmed. TW‐1, TW‐2, TW‐3, TW‐9, TW‐12, TW‐13 and TW‐14 were identified as Serratia marcescens; TW‐4, TW‐5, TW‐8 and TW‐10 as Staphylococcus sciuri; TW‐6 as Klebsiella pneumonia subsp. pneumonia; TW‐7 as Proteus vulgaris and TW‐11 as Proteus mirabilis. The preliminary single‐dose bioassay on fourth instar larvae showed that S. marcescens had a higher virulence at a density of 1.89 OD₆₀₀ (56.37% mortality) than the other strains. The corrected mortalities of the other strains were all less than 50%. The lowest toxicities were found for P. vulgaris and P. mirabilis where the corrected mortalities were only 28.18% and 25.57%, respectively. LC₅₀ of S. marcescens was 1.2 × 10⁷ CFU/ml inoculums. Our results indicated that S. marcescens from facultative cultivable bacterial flora isolated from R. ferrugineus could potentially be used as a microbial control agent for this widespread pest.     

Isolation and characterization of a highly sulfated heparan sulfate from ascidian test cells.

Several sulfated polysaccharides have been isolated from the test cells of the ascidian Styela plicata. The preponderant polysaccharide is a highly sulfated heparan sulfate with the following disaccharide composition: (1) UA(2SO4)-1-->4 GlcN(SO4)(6SO4), 53%; (2) UA(2SO4)-1-->4-GlcN(SO4), 22%; (3) UA-1-->4-GlcNAc(6SO4), 14% and (4) UA-1-->4-GlcN(SO4), 11%. Two others unidentified sulfated polysaccharides and a glycogen polymer are also present in the ascidian eggs. Histochemistry with the cationic dye 1,9-dimethyl-methylene blue and biochemical analysis of the 35S-sulfate incorporation into the eggs reveal that the sulfated glycans are present exclusively in the test cells. Possibly these sulfated polysaccharides are involved in important functions of these cells, such as to confer an external and hydrophilic layer which protect the eggs and the larvae of ascidians.     

高磷土壤中丛枝菌根真菌的分离鉴定

【背景】丛枝菌根(arbuscular mycorrhiza,AM)真菌具有广泛的寄主范围、环境适应性和优良的植物促生能力。然而,土壤的高磷水平严重抑制了AM真菌生长及AM形成。【目的】分离鉴定出耐较高有效磷含量的华南土著AM真菌菌株,为菌根学研究工作提供新颖材料。【方法】采用经典形态学和分子系统学方法鉴定高磷土壤中AM真菌。【结果】从有效磷含量为53-131 (平均值±标准差为88.2±17.6) mg/kg的根区土壤中鉴定出7属25种AM真菌,包括无梗囊霉属(Acaulospora) 12种、球囊霉属(Glomus) 7种、隔球囊霉属(Septoglomus) 2种、近明球囊霉属(Claroideoglomus) 1种、根孢囊霉属(Rhizophagus) 1种、硬囊霉属(Sclerocystis) 1种和类球囊霉属(Paraglomus) 1种,其中幼套近明球囊霉(Claroideoglomus etunicatum)和蜜色无梗囊霉(Acaulospora mellea)是优势种。在(87.7±8.0) mg/kg的高磷水平下,AM真菌仍能形成丛枝和泡囊。但当有效磷含量达到(99.7±1.2) mg/kg时,菌根侵染率和丛枝丰度显著下降,但仍能够形成泡囊。【结论】从广州市南沙区有效磷含量为(88.2±17.6) mg/kg的耕地植物根区土壤中,鉴定出具有耐高磷潜力的7属25种AM真菌,幼套近明球囊霉和蜜色无梗囊霉等分离株可作为后续高磷抑制机制解析及耐高磷AM真菌菌剂研发工作的试验菌株。     

广西传统发酵米粉中乳酸菌的分离鉴定

对广西传统米粉发酵液中的乳酸菌进行分离筛选,获得6株纯培养优势菌株。通过形态学鉴定及16S rDNA序列分析,结果表明其中4株乳酸菌属于戊糖片球菌(Pediococcus pentosaceus),另外2株鉴定为植物乳杆菌(Lactobacillus plantarum)。这2种乳酸菌均为对人类及动物安全的益生菌,该结果将为传统发酵米粉中有益微生物资源的挖掘和利用奠定基础。