Microbial diversity in uranium mine waste heaps

Microbial communities were characterized at contaminated sites that had elevated levels of nitrate, nickel, aluminum, and uranium (up to 690 mM, 310 microM, 42 mM, and 30 microM, respectively). The bacterial community structure based upon clonal libraries of the SSU rRNA genes (screened clones = 876) was diverse at the background site, but the three acidic samples had decreased diversity and the majority of clones were closely related to Azoarcus and Pseudomonas species. Arthrobacter and Novosphingobium sequences were recovered from the background samples but not the acidic sites, and similar pseudomonad populations were present at the background and acidic sites albeit at different relative abundances. Heterologous sequence coverage analyses indicated the microbial communities at the contaminated sites were very similar (p = 0.001) but different from the background site. Bacterial isolates (n = 67) classified as beta-or gamma-Proteobacteria, high G+C Gram-positive or low G+C Gram-positive were obtained from the background and one contaminated sample, and some of the isolates had less than 95% sequence identity with previously observed microorganisms. Despite variations in nitrate and heavy metal levels and different proximities to the source ponds, the three acidic samples had similar microbial populations. However, the least contaminated site (lowest nitrate and aluminum) had increased diversity compared to the other acidic samples. The results suggested that the combined contamination has decreased the microbial diversity, and Azoarcus populations were observed at a drastically increased frequency compared to the background site that had a more even distribution of multiple taxa.

Section: Sequence and Phylogenetic Analysismentioning

confidence: 99%

Impacts on microbial communities and cultivable isolates from groundwater contaminated with high levels of nitric acidâuranium waste

Fields

Tao

Rhee

et al. 2005

“…Tailing could thus be viewed as an extreme heavy-metal-contaminated environment that has adverse impacts on biological activity. Nonetheless, only few investigations have demonstrated that there are diverse lithotrophic and chemoorganotropic (COT) bacteria in sulfidic and uranium tailings [17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Genetic and physiological diversity of phylogenetically and geographically distinct groups of Arthrobacter isolated from leadâzinc mine tailings

Zhang

Duan

Qiyong

et al. 2004

The phylogenetic positions of 60 bacterial strains isolated from three tailing piles were determined by analyzing their partial 16S rRNA gene sequences. These strains were divided into three phylogenetically distinct groups of Arthrobacter and likely represented several non-described species. The physiological diversities of these phylogenetically and geographically distinct populations were evaluated based on their resistance to five heavy metals (Zn, Pb, Cd, Cu and Co) and four antibiotics (Kan, Rif, Str and Amp), and differences in utilization of 49 carbon sources. Genetic differentiations were demonstrated with randomly amplified polymorphic DNA (RAPD) analysis. These biological parameters were significantly different among three phylogenetically distinct groups. Notably, detectable differences were also observed among three geographically distinct subdivisions with similar taxonomic position. These results indicate that mine tailings are an ideal site for investigating the differentiation of natural bacterial populations in response to extreme metal contamination. Additionally, these environments appear to harbor many previously not characterized bacterial species, which are potentially important candidates for application in bioremediation due to their remarkable resistance to multiple metals.

“…Due to their impressive physiological diversity and the high resistance of their spores to unfavourable conditions, bacilli are widely distributed in a large variety of natural habitats [2,4^7]. It was demonstrated that in addition to the most abundant bacteria, the haemolithoautotrophic thiobacilli and leptospirilli, and the heterotrophic acidophili [8], some Bacillus sp. are also present in uranium waste piles [9].…”

Section: Introductionmentioning

confidence: 99%

Selective accumulation of heavy metals by three indigenous Bacillus strains, B. cereus, B. megaterium and B. sphaericus, from drain waters of a uranium waste pile

Selenska-Pobell¹

1999

The interaction was studied of three Bacillus isolates, recovered from a uranium waste pile in Saxony, Germany, with different heavy metal ions present in the original ground water of the pile. Using 16S amplified ribosomal DNA restriction and random amplified polymorphic DNA analyses, the three isolates were classified as B. cereus, B. megaterium and B. sphaericus. The ability was investigated of vegetative cells and spores of the indigenous Bacillus strains as well as those of the corresponding reference strains B. cereus ATCC 4415, B. megaterium NRRL B5385, and B. sphaericus NCTC 9602 to accumulate Al, Ba, Cd, Co, Cr, Cs, Cu, Fe, Ga, Mn, Ni, Rb, Pb, Si, Sn, Sr, Ti, U, and Zn. It was clearly shown that all strains studied accumulated selectively large amounts of U, Pb, Cd, Cu and Al. Co, Mn, Ni, Zn, and Ga was only weakly accumulated. The binding of Ba, Ga, Mn, Ni, and Zn was species and in some cases even strain specific. z