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1.
Joke Geets Brigitte Borremans Jaco Vangronsveld Ludo Diels Dani?l van der Lelie 《Journal of Soils and Sediments》2005,5(3):149-163
Background, Aims and Scope Sulfate-reducing bacteria (SRB) are known for their capacity to reduce and precipitate heavy metals (HM) as metal sulfides,
offering the opportunity to create an in situ reactive zone for the treatment of heavy metal-contaminated groundwater, a process
called in situ metal precipitation (ISMP). The applicability of the ISMP technology first has to be investigated at a laboratory
scale before going into an on site application. The evaluation and optimization of the ISMP process is facilitated when physical/chemical
analysis techniques are combined with molecular tools that specifically monitor the abundance, diversity and dynamics of the
indigenous sulfate reducing microbial community. In this study, batch experiments were conducted in order to investigate the
feasibility of ISMP as a groundwater remediation strategy for an industrial site contaminated with elevated levels of Zn,
Cd, Co and Ni.
Methods The potential of different types of carbon source/ electron donor (lactate, acetate, methanol, ethanol, Hydrogen Release
Compound?, molasses) to stimulate the sulfate reduction and metal precipitation activity of the naturally present (or indigenous)
SRB community was explored. In addition, the effect of amending vitamin B12 and yeast extract was evaluated. The ISMP process
was monitored by combining analytical analyzes of process parameters (SO42-concentration, heavy metal concentrations,
pH, Eh) with molecular tools such as SRB subgroup and genus specific PCR, denaturing gradient gel electrophoresis (DGGE),
and phylogenetic analysis of clone sequences, based on either the 16S rRNA or the dsr (dissimilatory sulfite reductase) gene.
Results and Discussion The efficiency of different carbon-sources to stimulate the ISMP process followed the order HRC 〉 molasses 〉 methanol
〉 lactate 〉 ethanol 〉 acetate. Within 10 weeks, the highest sulfate and metal removal efficiencies ranged from 85% to 99%.
Addition of yeast extract boosted the ISMP process, whereas vitamin B12 negligibly affected SRB activity. Analysis of the
sulfate reducing population by SRB subgroup and genus specific PCR demonstrated that members of the genus Desulfosporosinus
dominated in all batch tests, while 16S rDNA DGGE profiles additionally revealed the presence in the microbial communities
of non-sulfate reducing bacteria within the family Clostridium and the -proteobacteria. The dsrB-based DGGE profiles
allowed us to assess the diversity and dynamics of the sulfate reducing community and added to a better understanding of the
effects of different batch conditions on the ISMP process. Remarkably, all dsrB sequences affiliated with the dsrB gene sequence
cluster found in Desulfotomaculum, which received their xenologous dsrB gene from the -proteobacteria.
Conclusions The batch experiments, which aimed at stimulating the activities of the indigenous SRB communities, demonstrated that these
communities were present and that their activities could be used to obtain efficient in situ precipitation of the contaminating
heavy metals. This opens the possibility to test this concept in the future as an on site demonstration as part of the groundwater
strategy for the heavy metal contaminated site. Although batch setups are suitable for preliminary feasibility studies for
ISMP, they do not reflect the in situ situation where sulfate and heavy metal and metalloid polluted groundwater are supplied
continuously. A sulfate reducing strain JG32A was isolated from whose 16S rRNA gene affiliated with the genus Desulfosporosinus,
while its dsrB gene sequence clustered with Desulfotomaculum dsrB gene sequences, which received their xenologous dsr genes
from -proteobacteria. Therefore we hypothesize that the batch experiments enrich members of the Desulfosporosinus
genus that possess a non-orthologous dsrB gene.
Recommendation and Perspective The next step towards an on site pilot test for ISMP will be the setup of a series of column experiments, with process conditions
that are selected based on the above mentioned results. This will allow to define optimal ISMP process conditions and to test
its long-term efficacy and sustainability before going into an on site bioremediation application. By applying the described
molecular tools together with physical-chemical analyzes, it can be investigated whether the same SRB community is enriched
and which type of C-source is most effective in promoting and sustaining its growth and sulfate-reduction activity. 相似文献
2.
3.
Christine?LachmundEmail author Beate?K?cher Werner?Manz Peter?Heininger 《Journal of Soils and Sediments》2003,3(3):188-196
Background River sediments are natural habitats of complex bacterial and fungal communities and therefore play a decisive role in the
mineralization process of organic matter in freshwater systems. By means of comparative temporal and spatial analyses of microbial
communities, the in situ impact of anthropogenically generated pollutants on these biofilm associations can be assessed and discriminated from seasonal
variations.
Aim The aim was the adaptation of hybridization with fluorescently labelled rRNA-targeted oligonucleotides (FISH) for the in situ characterization of the structural and functional diversity of native microbial communities in complex lotic sediments. The
impact of qualitatively and quantitatively different water pollutants on the microbial diversity, metabolic potential, and
relative abundance of characteristic bacterial groups was assessed by oligonucleotide probes on different phylogenetic levels.
In particular, sulfate reducing bacteria (SRB) were investigated to evaluate their potential applicability as microbial biomonitors
in sediments.
Methods Sediment samples from the German lowland rivers Elbe and Oder were investigated over 12 months with regard to physico-chemical
parameters and the composition of the attached microbial communities. Mechanical treatment including ultrasonification and
sagitation under aerobic conditions combined with the use of pyrophosphate ensured the equal dispersion of fixed microbial
cells within the sediment samples. The optimized whole-sediment FISH-technique was combined with an improved cell extraction
procedure and applied, due to the specific grain size fraction distribution, at the different sampling sites.
Resultsand discussion Up to 85.6% of the total bacterial cell counts as determined by DAPI (4’, 6-diamidino-2-phenylindole) staining could be successfully
monitored by the eubacterial oligonucleotide probe set EUB338, EUB338-II and EUB338-III, simultaneously indicating a high
proportion of Eubacteria and the high metabolic potential of the bacterial community. Desulfobacteriaceae could be detected by the specific probe SRB385Db in various relative percentages ranging from 2.4 to 16.0% of the total bacterial
cell counts. The total number of bacteria and the metabolic potential of sediment related bacteria were barely affected by
the different pollution pattern of the sampling sites.
Conclusions The pre-treatment step as conducted by cell extraction as well as the FISH hybridization procedure was successfully optimized
to the specific conditions present within freshwater sediments. Beside seasonal variations, particularly occurring at hydrologically
influenced sites, sampling sites with different pol lution levels could be successfully distinguished by the relative abundance
of Desulfobacteriaceae used as microbial indicator organisms.
Outlook The integration of ongoing insights into pollution induced changes of natural bacterial consortia should result in a system
of ecotoxicological classes representing the different ecological status of riverine systems. Physiological directed methods
like Community Level Physiological Profiling (CLPP) or Pollution Induced Community Tolerance (PICT), and structural techniques
as FISH or microarrays should be used to investigate the influence of harmful substances on the biodiversity in natural microbial
sediment communities. 相似文献
4.
大鹏澳网箱养殖区沉积物硫酸盐还原菌(SRB)及其与环境因子关系的初步研究 总被引:1,自引:0,他引:1
实验采用MPN法测定了大鹏澳网箱养殖区沉积物中硫酸盐还原菌(SRB)的含量,布设的5个站位SRB检出率达100%,SRB平面分布特征是鱼类网箱区>对照区>浮筏贝类区;垂直分布特征为1cm层>5cm层>10cm层,SRB数量是由上向下逐渐减少。探讨了SRB含量与相应沉积物样品中的硫化物含量、氧化还原电位、pH等环境因子的关系。结果表明,沉积物中SRB数量与硫化物含量呈显著性正相关(R=0.96,P<0.05),与氧化还原电位(OPR)呈极显著性负相关(R=-0.97,P<0.01),与pH之间不具有显著性关系。 相似文献
5.
重金属污染对水稻田土壤硫酸盐还原菌种群数量及其活性的影响 总被引:4,自引:0,他引:4
在实验室条件下,采用重金属Cd2+、As5+、Cu2+、Pb2+和Cr3+处理黄松稻田土壤、紫色稻田土壤和红壤稻田土,28d后分析重金属污染对水稻田土壤的硫酸盐还原菌(SRB)种群数量和硫酸盐还原活性(SRA)的影响。结果表明,在每千克干土中加入200mgPb2+时,对稻田土壤的SRB种群数量和SRA有促进作用;当加入的Cd2+、As5+、Cu2+、Pb2+和Cr3+每千克干土分别超过1.0、30、500、400和200mg时,对稻田土壤SRB种群数量和SRA有明显抑制作用。随着加入量的增加,重金属对水稻田土壤的SRB种群数量和SRA的抑制作用越来越强,水稻田土壤通过自身来恢复SRB种群数量和SRA所需的时间也越长。同一种重金属元素对不同土壤的SRB种群数量和SRA抑制的污染临界值也有差异。 相似文献
6.
红外光谱结合元素分析法研究SRB对煤的降解 总被引:1,自引:0,他引:1
利用傅里叶红外光谱(FTIR)技术,对淮南潘二煤层煤样在接种硫酸盐还原菌(SRB)前后煤样组分的结构变化特征及规律进行研究,同时结合元素分析技术进行进一步分析。结果表明,煤样经过SRB细菌降解后,S元素、N元素均有不同幅度变化,其中,S元素均有减小的趋势,N元素有小幅度的增加趋势。C、H元素变化不明显,同时SRB细菌将煤中能降解利用的有机物降解后,煤样中含氧官能团相对含量下降、羟基官能团含量有所上升。SRB细菌的降解利用改变了煤中有机物成分含量及物质结构。 相似文献
7.
高硫酸盐有机废水厌氧处理技术的进展 总被引:34,自引:2,他引:32
本文通过硫酸盐还原菌和产甲烷菌的竞争、硫化物对产甲烷菌的毒害二方面,论述了在高硫酸盐有机废水厌氧处理过程中,硫酸盐还原作用对产甲烷菌活性的抑制机理,同时,介绍了当前高硫酸盐有机废水的厌氧处理工艺 相似文献
8.
籼粳稻杂交理想株型创造与超高产育种及其应用研究 总被引:4,自引:1,他引:3
《沈阳农业大学学报》1999,30(4):397-403
几十年来在籼粳稻杂交育种、水稻理想株型及超高产育种领域完成了大量开拓性应用基础研究,首次提出了籼粳稻杂交育种的关键技术,即通过生物学方法克服籼粳杂交产生的疯狂分离、结实率低和后代不易稳定三大困难以及有利综合籼粳优点的亲本和杂交后代选择技术,使之成为行之有效的常规育种方法,使我国成为世界上籼粳稻杂交育种最成功的国家:在籼粳稻杂交育种基础上,首次明确提出通过籼粳稻杂交创造株型变异、进行理想株型育种的理 相似文献
9.
Oluwaseun Oyekola 《Soil biology & biochemistry》2006,38(12):3511-3515
Adenosine triphosphate-sulphurylase (ATPS) plays a major role in dissimilatory sulphate reduction. In this study, the level of ATPS activity was monitored in a time course study using a biosulphidogenic batch bioreactor system. A coincident decrease in ATPS activity with a decline in sulphate concentration and an increase in sulphide concentration as biosulphidogenesis proceeded was observed. Flask studies further showed sulphate to be stimulatory to ATPS, while sulphide proved to be inhibitory. The effect of ions (Ca2+, Cl−, Fe2+ and Zn2+) on the ATPS activity was also investigated. Most of the ions studied (Ca2+, Cl− and Fe2+) were stimulatory at lower concentrations (40-120 mg/l) but proved toxic at higher concentrations (>120 mg/l). In contrast, Zn2+ was inhibitory even at low concentrations (?40 mg/l). ATPS may potentially be used as an enzymatic marker for biological sulphate reduction in sulphate-rich wastewaters and natural environments (anaerobic systems such as soils and sediments found in freshwater and marine systems), providing all residual sulphide and interfering ions are removed using a simple preparative step. 相似文献
10.
Akihiro Ohsumi Toshiyuki Takai Masashi Ida Toshio Yamamoto Yumiko Arai-Sanoh Masahiro Yano Tsuyu Ando Motohiko Kondo 《Field Crops Research》2011
Rice yield potential is determined by the balance between sink size and source capacity. To clarify the factors that limit yield in temperate japonica cultivars, we compared the yield performance of Sasanishiki, a temperate japonica cultivar, with those of three near-isogenic lines (NILs) of Sasanishiki with introgression of quantitative trait loci (QTL) derived from a high-yielding indica cultivar, Habataki: qSBN1, which increases the number of secondary rachis branches; qPBN6, which increases the number of primary rachis branches; and a pyramid line that combines these two QTLs. NIL (SBN1), NIL (PBN6), and NIL (SBN1 + PBN6) produced 28–37%, 9–16%, and 62–65% more spikelets per panicle than Sasanishiki, respectively. However, the NILs with increased spikelet number per panicle did not increase grain yield significantly, because compensation is taken place among different yield components. The pyramid line nevertheless had 4–12% higher yield than Sasanishiki due to greater translocation of carbohydrates from stem to panicle. There was no difference in carbohydrate accumulation before heading or in biomass production among Sasanishiki and the three NILs. The results indicate that increasing sink size does not substantially improve yield in Sasanishiki, which lacks sufficient substrate supply to fully satisfy the increased sink demand that results from the spikelet-number QTLs. 相似文献