scholarly journals 16S rRNA Gene-Based Profiling of the Microbial Community in an Acid Mine Drainage Fe Precipitate at Libiola Mine (Liguria, Italy)

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1064
Author(s):  
Sirio Consani ◽  
Stefano Ghignone ◽  
Marina Pozzolini ◽  
Marco Giovine ◽  
Luigi Vezzulli ◽  
...  

Acid mine drainage (AMD) is a common environmental problem in many sulphide mines worldwide, and it is widely accepted that the microbial community plays a major role in keeping the process of acid generation active. The aim of this work is to describe, for the first time, the microbial community thriving in goethite and jarosite Fe precipitates from the AMD of the Libiola mine. The observed association is dominated by Proteobacteria (>50%), followed by Bacteroidetes (22.75%), Actinobacteria (7.13%), Acidobacteria (5.79%), Firmicutes (2.56%), and Nitrospirae (1.88%). Primary producers seem to be limited to macroalgae, with chemiolithotrophic strains being almost absent. A phylogenetic analysis of bacterial sequences highlighted the presence of heterotrophic bacteria, including genera actively involved in the AMD Fe cycle and genera (such as Cytophaga and Flavobacterium) that are able to reduce cellulose. The Fe precipitates constitute a microaerobic and complex environment in which many ecological niches are present, as proved by the wide range of bacterial species observed. This study is the first attempt to quantitatively characterize the microbial community of the studied area and constitutes a starting point to learn more about the microorganisms thriving in the AMD of the Libiola mine, as well as their potential applications.

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
Tebogo M. Mokgehle ◽  
Nikita T. Tavengwa

AbstractAcid mine drainage is the reaction of surface water with sub-surface water located on sulfur bearing rocks, resulting in sulfuric acid. These highly acidic conditions result in leaching of non-biodegradeable heavy metals from rock which then accumulate in flora, posing a significant environmental hazard. Hence, reliable, cost effective remediation techniques are continuously sought after by researchers. A range of materials were examined as adsorbents in the extraction of heavy metal ions from acid mine drainage (AMD). However, these materials generally have moderate to poor adsorption capacities. To address this problem, researchers have recently turned to nano-sized materials to enhance the surface area of the adsorbent when in contact with the heavy metal solution. Lately, there have been developments in studying the surface chemistry of nano-engineered materials during adsorption, which involved alterations in the physical and chemical make-up of nanomaterials. The resultant surface engineered nanomaterials have been proven to show rapid adsorption rates and remarkable adsorption capacities for removal of a wide range of heavy metal contaminants in AMD compared to the unmodified nanomaterials. A brief overview of zeolites as adsorbents and the developent of nanosorbents to modernly applied magnetic sorbents and ion imprinted polymers will be discussed. This work provides researchers with thorough insight into the adsorption mechanism and performance of nanosorbents, and finds common ground between the past, present and future of these versatile materials.


2003 ◽  
Vol 69 (9) ◽  
pp. 5512-5518 ◽  
Author(s):  
Brett J. Baker ◽  
Philip Hugenholtz ◽  
Scott C. Dawson ◽  
Jillian F. Banfield

ABSTRACT During a molecular phylogenetic survey of extremely acidic (pH < 1), metal-rich acid mine drainage habitats in the Richmond Mine at Iron Mountain, Calif., we detected 16S rRNA gene sequences of a novel bacterial group belonging to the order Rickettsiales in the Alphaproteobacteria. The closest known relatives of this group (92% 16S rRNA gene sequence identity) are endosymbionts of the protist Acanthamoeba. Oligonucleotide 16S rRNA probes were designed and used to observe members of this group within acidophilic protists. To improve visualization of eukaryotic populations in the acid mine drainage samples, broad-specificity probes for eukaryotes were redesigned and combined to highlight this component of the acid mine drainage community. Approximately 4% of protists in the acid mine drainage samples contained endosymbionts. Measurements of internal pH of the protists showed that their cytosol is close to neutral, indicating that the endosymbionts may be neutrophilic. The endosymbionts had a conserved 273-nucleotide intervening sequence (IVS) in variable region V1 of their 16S rRNA genes. The IVS does not match any sequence in current databases, but the predicted secondary structure forms well-defined stem loops. IVSs are uncommon in rRNA genes and appear to be confined to bacteria living in close association with eukaryotes. Based on the phylogenetic novelty of the endosymbiont sequences and initial culture-independent characterization, we propose the name “Candidatus Captivus acidiprotistae.” To our knowledge, this is the first report of an endosymbiotic relationship in an extremely acidic habitat.


2018 ◽  
Vol 247 ◽  
pp. 624-632 ◽  
Author(s):  
Yaneth Vasquez ◽  
Maria C. Escobar ◽  
Johan S. Saenz ◽  
Maria F. Quiceno-Vallejo ◽  
Carmen M. Neculita ◽  
...  

Author(s):  
Christen L. Grettenberger ◽  
Trinity L. Hamilton

Acid mine drainage (AMD) is a global problem in which iron sulfide minerals oxidize and generate acidic, metal-rich water. Bioremediation relies on understanding how microbial communities inhabiting an AMD site contribute to biogeochemical cycling. A number of studies have reported community composition in AMD sites from 16S rRNA gene amplicons but it remains difficult to link taxa to function, especially in the absence of closely related cultured species or those with published genomes. Unfortunately, there is a paucity of genomes and cultured taxa from AMD environments. Here, we report 29 novel metagenome assembled genomes from Cabin Branch, an AMD site in the Daniel Boone National Forest, KY, USA. The genomes span 11 bacterial phyla and one Archaea and include taxa that contribute to carbon, nitrogen, sulfur, and iron cycling. These data reveal overlooked taxa that contribute to carbon fixation in AMD sites as well as uncharacterized Fe(II)-oxidizing bacteria. These data provide additional context for 16S rRNA gene studies, add to our understanding of the taxa involved in biogeochemical cycling in AMD environments, and can inform bioremediation strategies. IMPORTANCE Bioremediating acid mine drainage requires understanding how microbial communities influence geochemical cycling of iron and sulfur and biologically important elements like carbon and nitrogen. Research in this area has provided an abundance of 16S rRNA gene amplicon data. However, linking these data to metabolisms is difficult because many AMD taxa are uncultured or lack published genomes. Here, we present metagenome assembled genomes from 29 novel AMD taxa and detail their metabolic potential. These data provide information on AMD taxa that could be important for bioremediation strategies including taxa that are involved in cycling iron, sulfur, carbon, and nitrogen.


2020 ◽  
Author(s):  
Sarah Zecchin ◽  
Nicoletta Guerrieri ◽  
Evelien Jongepier ◽  
Leonardo Scaglioni ◽  
Gigliola Borgonovo ◽  
...  

&lt;p&gt;Arsenic is a toxic but naturally abundant metalloid that globally leads to contamination in groundwater and soil, exposing millions of people to cancer and other arsenic-related diseases. In several areas in Northern Italy arsenic in soil and water exceeds law limits (20 mg kg&lt;sup&gt;-1&lt;/sup&gt; and 10 mg L&lt;sup&gt;-1&lt;/sup&gt;, respectively), due to both the mineralogy of bedrock and former mining activities. The Rio Rosso stream, located in the Anzasca Valley (Piedmont) is heavily affected by an acid mine drainage originated from an abandoned gold mine. Arsenic, together with other heavy metals, is transferred by the stream to the surrounding area. The stream is characterized by the presence of an extensive reddish epilithic biofilm at the opening of the mine and on the whole contaminated waterbed.&lt;/p&gt; &lt;p&gt;The aim of this study was to characterize the mechanisms allowing the biotic fraction of this biofilm to cope with extreme arsenic concentrations. The composition and functionality of the microbial communities constituting the epilithic biofilms sampled in the close proximity and downstream the mine were unraveled by 16S rRNA genes and shotgun Illumina sequencing in relation to the extreme physico-chemical parameters. In parallel, autotrophic and heterotrophic microbial populations were characterized &lt;em&gt;in vivo&lt;/em&gt; by enrichment cultivation and isolated strains were tested for their ability to perform arsenic redox transformation.&lt;/p&gt; &lt;p&gt;Preliminary analyses indicated that the biofilm accumulated arsenic in the order of 6 &amp;#183; 10&lt;sup&gt;3&lt;/sup&gt; mg kg&lt;sup&gt;-1&lt;/sup&gt;, in contrast to 0.14 mg L&lt;sup&gt;-1&lt;/sup&gt;, measured in the surrounding water. The main chemical parameter affecting the composition of the microbial community was the pH, being 2 next to the mine and 6.7 in the downstream sampling point. In both sampling sites iron- and sulfur-cycling microorganisms were retrieved by both cultivation and molecular methods. However, the diversity of the microbial community living next to the mine was significantly lower with respect to the community developed downstream. In the latter, autotrophic &lt;em&gt;Cyanobacteria&lt;/em&gt; belonging to the species &lt;em&gt;Tychonema&lt;/em&gt; were the dominant taxa. A complete arsenic cycle was shown to occur, with heterotrophic bacteria mainly responsible for arsenate reduction and autotrophic bacteria performing arsenite &amp;#160;oxidation.&lt;/p&gt; &lt;p&gt;These observations indicate that the epilithic biofilm living in the Rio Rosso stream represents a peculiar ecosystem where microorganisms cope with metalloid toxicity likely using diverse mechanisms. Such microbial metabolic properties might be exploited in bioremediation strategies applied in arsenic-contaminated environments.&lt;/p&gt;


Microbiology ◽  
2016 ◽  
Vol 85 (4) ◽  
pp. 449-461 ◽  
Author(s):  
V. V. Kadnikov ◽  
D. A. Ivasenko ◽  
A. V. Beletskii ◽  
A. V. Mardanov ◽  
E. V. Danilova ◽  
...  

2013 ◽  
Vol 93 (2) ◽  
pp. 108-115 ◽  
Author(s):  
Ryan R. Auld ◽  
Maxine Myre ◽  
Nadia C.S. Mykytczuk ◽  
Leo G. Leduc ◽  
Thomas J.S. Merritt

2017 ◽  
Vol 93 (10) ◽  
Author(s):  
Jie-Liang Liang ◽  
Xiao-Jing Li ◽  
Hao-Yue Shu ◽  
Pandeng Wang ◽  
Jia-Liang Kuang ◽  
...  

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