Publications by authors named "Edgardo Donati"

29 Publications

  • Page 1 of 1

Evaluation of the sequential coupling of a bacterial treatment with a physicochemical process for the remediation of wastewater containing Cr and organic pollutants.

J Hazard Mater 2021 Jun 6;418:126307. Epub 2021 Jun 6.

Planta Piloto de Procesos Industriales Microbiológicos (PROIMI), CONICET, Av. Belgrano y Pasaje Caseros, 4000 Tucumán, Argentina; Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán, Miguel Lillo 205, 4000 Tucumán, Argentina. Electronic address:

A restoration strategy was developed for the treatment of two artificial liquid systems (Minimal Medium, MM, and Water Carbon Nitrogen, WCN) contaminated with Cr(VI), lindane (γ-HCH), phenanthrene (Phe), and reactive black 5 (RB5), through the use of an actinobacteria consortium, coupled with a physicochemical treatment using a column filled with nano-scale zero valent iron particles immobilized on dried Macrocystis pyrifera algae biomass. The Sequential Treatment A (ST: physicochemical followed by biological method) removed the three organic compounds with different effectiveness; however, it was very ineffective for Cr(VI) removal. The Sequential Treatment B (ST: biological followed by the physicochemical method) removed the four compounds with variable efficiencies. The removal of γ-HCH, Phe, and RB5 in both effluents did not present significant differences, regardless of the sequential treatment used. The highest removal of Cr(VI) and total Cr was observed in MM and WCN, respectively. Ecotoxicity tests (L. sativa) of the effluents treated with both methodological couplings demonstrated that the toxicity of WCN only decreased at the end of ST, while that of MM decreased at all stages of both sequential treatments. Therefore, MM would be more appropriate to perform both treatments.
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http://dx.doi.org/10.1016/j.jhazmat.2021.126307DOI Listing
June 2021

Influence of Extremophiles on the Generation of Acid Mine Drainage at the Abandoned Pan de Azúcar Mine (Argentina).

Microorganisms 2021 Jan 29;9(2). Epub 2021 Jan 29.

Centro de Investigación y Desarrollo en Fermentaciones Industriales, CINDEFI (CCT La Plata-CONICET, UNLP), Facultad de Ciencias Exactas, 50 y 115, La Plata 1900, Argentina.

The risk of generation of acid drainages in the tailings of the Pan de Azúcar mine that closed its activities more than three decades ago, was evaluated through biooxidation studies using iron- and sulfur-oxidizing extremophilic leaching consortia. Most of tailings showed a high potential for generating acid drainage, in agreement with the results from net acid generation (NAG) assays. In addition, molecular analysis of the microbial consortia obtained by enrichment of the samples, demonstrated that native leaching microorganisms are ubiquitous in the area and they seemed to be more efficient in the biooxidation of the tailings than the collection microorganisms. The acid drainages detected at the site and those formed by oxidation of the tailings, produced a significant ecotoxicological effect demonstrated by a bioassay. These drainages, even at high dilutions, could seriously affect a nearby Ramsar site (Laguna de Pozuelos) that is connected to the Pan de Azúcar mine through a hydrological route (Cincel River).
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http://dx.doi.org/10.3390/microorganisms9020281DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7912565PMC
January 2021

Acidophilic microorganisms enhancing geochemical dynamics in an acidic drainage system, Amarillo river in La Rioja, Argentina.

Chemosphere 2021 Jan 27;263:128098. Epub 2020 Aug 27.

Centro de Investigación y Desarrollo en Fermentaciones Industriales (CINDEFI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Calle 50 288, La Plata, Argentina; Universidad Nacional de La Plata (UNLP), Calle 47 y 115, La Plata, Buenos Aires, Argentina. Electronic address:

The Amarillo River in La Rioja, Argentina, is a natural acidic environment that is influenced by an abandoned mine. The river is characterized by extremely low pH and high concentrations of metals and metalloids. Fe(III)-bearing neoformed precipitated minerals are widespread along the hydrological basin. This work reports the presence of different species of iron-oxidizing bacteria and demonstrates that their action has a significant role in geochemical processes of the Amarillo River, mainly by catalyzing Fe oxidation and intensifying the Fe(III)-bearing mineral precipitation. Various iron oxidizers (i.e. Acidithiobacillus ferrivorans, Leptospirillum ferrooxidans, Ferrimicrobium acidophilum, Alicyclobacillus cycloheptanicus) were detected in enrichment cultures at different temperatures. Moreover, this is the first report confirming that Acidithiobacillus ferrivorans is able to grow at 4 °C. Other acidophilic bacteria (i.e., Acidiphilium iwatensii) and fungi (e.g., Fodinomyces uranophilus, Coniochaeta fodinicola, Acidea extrema, Penicillium sp. and Cladosporium pseudocladosporioides) were also detected. In vitro laboratory studies recreating natural Fe(III)-bearing mineral formation showed that mineral precipitation rate was higher than 350 mg L day in the presence of microorganisms whereas it was about 15 mg L day under abiotic conditions. Jarosite was the only mineral detected in the precipitates generated by microbial action and it was also identified in the Amarillo River bed sediments. Biological Fe oxidation rates depend on temperature which range from 8 to 32 mM day at 4 and 30 °C, respectively. Finally, a conceptual model recognizing the significant microbial role is proposed to gain a better understanding of the biogeochemistry dynamics of the Amarillo River.
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http://dx.doi.org/10.1016/j.chemosphere.2020.128098DOI Listing
January 2021

Effect of heavy metal-induced stress on two extremophilic microbial communities from Caviahue-Copahue, Argentina.

Environ Pollut 2021 Jan 24;268(Pt B):115709. Epub 2020 Sep 24.

CINDEFI (CONICET, UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina. Electronic address:

Metal pollution is a great concern worldwide and the development of new technologies for more sustainable extraction methods as well as for the remediation of polluted sites is essential. Extremophilic microorganisms are attractive for this purpose since they have poly-resistance mechanisms which make them versatile. In this work, we sampled an acidic river and a hot spring of Caviahue-Copahue volcanic environment. The indigenous microbial communities were exposed to five heavy metals (Cd, Co, Cu, Ni and Zn) in batch-cultures favouring different metabolisms of biotechnological interest. Remarkably, high tolerance values were reached in all the cultures, even though most of the metals studied were not present in the environmental sample. Particularly, outstanding tolerances were exhibited by acidophiles, which grew at concentrations as high as 400 mM of Zn and Ni. High-throughput amplicon sequencing of 16S rRNA gene was used to study the indigenous communities and the resistant consortia. We took three approaches for the analysis: phylotypes, OTUs and amplicon sequence variants (ASVs). Interestingly, similar conclusions were drawn in all three cases. Analysing the phylogenetic structure and functional potential of the adapted consortia, we found that the strongest selection was exerted by the culture media. Notably, there was a poor correlation between alpha diversity and metal stress; furthermore, metal stress did not seem to harm the functional potential of the consortia. All these results reveal a great adaptability and versatility. At the end, 25 metal-resistant extremophilic consortia with potential uses in bioremediation, bioleaching or biomonitoring processes were obtained.
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http://dx.doi.org/10.1016/j.envpol.2020.115709DOI Listing
January 2021

Importance of Initial Interfacial Steps during Chalcopyrite Bioleaching by a Thermoacidophilic Archaeon.

Microorganisms 2020 Jul 6;8(7). Epub 2020 Jul 6.

CINDEFI (CCT La Plata -CONICET, U.N.L.P.), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata 1900, Argentina.

Studies of thermophilic microorganisms have shown that they have a considerable biotechnological potential due to their optimum growth and metabolism at high temperatures. Thermophilic archaea have unique characteristics with important biotechnological applications; many of these species could be used in bioleaching processes to recover valuable metals from mineral ores. Particularly, bioleaching at high temperatures using thermoacidophilic microorganisms can greatly improve metal solubilization from refractory mineral species such as chalcopyrite (CuFeS), one of the most abundant and widespread copper-bearing minerals. Interfacial processes such as early cell adhesion, biofilm development, and the formation of passive layers on the mineral surface play important roles in the initial steps of bioleaching processes. The present work focused on the investigation of different bioleaching conditions using the thermoacidophilic archaeon DSM 29038 to elucidate which steps are pivotal during the chalcopyrite bioleaching. Fluorescent in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM) were used to visualize the microorganism-mineral interaction. Results showed that up to 85% of copper recovery from chalcopyrite could be achieved using . Improvements in these yields are intimately related to an early contact between cells and the mineral surface. On the other hand, surface coverage by inactivated cells as well as precipitates significantly reduced copper recoveries.
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http://dx.doi.org/10.3390/microorganisms8071009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7409349PMC
July 2020

Meta-Analysis of Microbial Communities in Hot Springs: Recurrent Taxa and Complex Shaping Factors beyond pH and Temperature.

Microorganisms 2020 Jun 16;8(6). Epub 2020 Jun 16.

CINDEFI (CCT, La Plata-CONICET, UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, 1900 Buenos Aires, Argentina.

The study of microbial communities from extreme environments is a fascinating topic. With every study, biologists and ecologists reveal interesting facts and questions that dispel the old belief that these are inhospitable environments. In this work, we assess the microbial diversity of three hot springs from Neuquén, Argentina, using high-throughput amplicon sequencing. We predicted a distinct metabolic profile in the acidic and the circumneutral samples, with the first ones being dominated by chemolithotrophs and the second ones by chemoheterotrophs. Then, we collected data of the microbial communities of hot springs around the world in an effort to comprehend the roles of pH and temperature as shaping factors. Interestingly, there was a covariation between both parameters and the phylogenetic distance between communities; however, neither of them could explain much of the microbial profile in an ordination model. Moreover, there was no correlation between alpha diversity and these parameters. Therefore, the microbial communities' profile seemed to have complex shaping factors beyond pH and temperature. Lastly, we looked for taxa associated with different environmental conditions. Several such taxa were found. For example, was frequently present in acidic springs, as was the Sulfolobaceae family; on the other hand, Hydrothermae phylum was strongly associated with circumneutral conditions. Interestingly, some singularities related to sites featuring certain taxa were also observed.
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http://dx.doi.org/10.3390/microorganisms8060906DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7356817PMC
June 2020

Isolated from a Pristine Natural Geothermal Area Reveals High Keratinolytic Activity.

Microorganisms 2020 May 26;8(6). Epub 2020 May 26.

CINDEFI (CCT La Plata-CONICET, UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calle 47 y 115, (B1900ASH) La Plata 1900, Argentina.

Geothermal areas are the niches of a rich microbial diversity that is not only part of the intangible patrimony of a country but also the source of many microbial species with potential biotechnological applications. Particularly, microbial species in geothermal areas in Argentina have been scarcely explored regarding their possible biotechnological uses. The purpose of this work was to explore the proteolytic and keratinolytic enzymatic potential of microorganisms that inhabit in the Domuyo geothermal area in the Neuquén Province. To this end, we did enrichment cultures from two high-temperature natural samples in mineral media only supplemented with whole chicken feathers. After the isolation and the phylogenetic and morphologic characterization of different colonies, we obtained a collection of isolates, a species with no previous report of keratinolytic activity and only reported in rehydrated meals connected with food poisoning outbreaks. Its natural habitat has been unknown up to now. We characterized the proteolytic and keratinolytic capacities of the isolates in different conditions, which proved to be remarkably high compared with those of other similar species. Thus, our work represents the first report of the isolation as well as the keratinolytic capacity characterization of strains of obtained from a natural environment.
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http://dx.doi.org/10.3390/microorganisms8060796DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7355561PMC
May 2020

A Deeper Look into the Biodiversity of the Extremely Acidic Copahue volcano-Río Agrio System in Neuquén, Argentina.

Microorganisms 2019 Dec 29;8(1). Epub 2019 Dec 29.

CINDEFI (CONICET-CCT LA PLATA, UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calles 47 y 115, 1900 La Plata, Argentina.

The Copahue volcano-Río Agrio system, on Patagonia Argentina, comprises the naturally acidic river Río Agrio, that runs from a few meters down the Copahue volcano crater to more than 40 km maintaining low pH waters, and the acidic lagoon that sporadically forms on the crater of the volcano, which is studied for the first time in this work. We used next-generation sequencing of the 16S rRNA gene of the entire prokaryotic community to study the biodiversity of this poorly explored extreme environment. The correlation of the operational taxonomic units (OTUs)s presence with physicochemical variables showed that the system contains three distinct environments: the crater lagoon, the Upper Río Agrio, and the Salto del Agrio waterfall, a point located approximately 12 km down the origin of the river, after it emerges from the Caviahue lake. The prokaryotic community of the Copahue Volcano-Río Agrio system is mainly formed by acidic bacteria and archaea, such as , and , which have been isolated from similar environments around the world. These results support the idea of a ubiquitous acidic biodiversity; however, this highly interesting extreme environment also has apparently autochthonous species such as , and strains of and .
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http://dx.doi.org/10.3390/microorganisms8010058DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7027000PMC
December 2019

Enrichment and isolation of acid-tolerant sulfate-reducing microorganisms in the anoxic, acidic hot spring sediments from Copahue volcano, Argentina.

FEMS Microbiol Ecol 2019 12;95(12)

School of Natural Sciences, Bangor University, Deiniol Road, Bangor, LL57 2UW, UK.

The geothermal Copahue-Caviahue (GCC) system (Argentina) is an extreme acidic environment, dominated by the activity of Copahue volcano. Environments characterised by low pH values, such as volcanic areas, are of particular interest for the search of acidophilic microorganisms with application in biotechnological processes. In this work, sulfate-reducing microorganisms were investigated in geothermal acidic, anaerobic zones from GCC system. Sediment samples from Agua del Limón (AL1), Las Máquinas (LMa2), Las Maquinitas (LMi) and Baño 9 (B9-2, B9-3) were found to be acidic (pH values 2.1-3.0) to moderate acidic (5.1-5.2), containing small total organic carbon values, and ferric iron precipitates. The organic electron donor added to the enrichment was completely oxidised to CO2. Bacteria related to 'Desulfobacillus acidavidus' strain CL4 were found to be dominant (67-83% of the total number of clones) in the enrichment cultures, and their presence was confirmed by their isolation on overlay plates. Other bacteria were also detected with lower abundance (6-20% of the total number of clones), with representatives of the genera Acidithiobacillus, Sulfobacillus, Alicyclobacillus and Athalassotoga/Mesoaciditoga. These enrichment and isolates found at low pH confirm the presence of anaerobic activities in the acidic sediments from the geothermal Copahue-Caviahue system.
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http://dx.doi.org/10.1093/femsec/fiz175DOI Listing
December 2019

Editorial: Recent Advances in Bioremediation/Biodegradation by Extreme Microorganisms.

Front Microbiol 2019 14;10:1851. Epub 2019 Aug 14.

Division of Genetics and Molecular Biology, Faculty of Science, Institute of Biological Sciences, University of Malaya, Kuala Lumpur, Malaysia.

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http://dx.doi.org/10.3389/fmicb.2019.01851DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6703092PMC
August 2019

Arsenic-tolerant microbial consortia from sediments of Copahue geothermal system with potential applications in bioremediation.

J Basic Microbiol 2019 Jul 20;59(7):680-691. Epub 2019 May 20.

Centro de Investigación y Desarrollo de Fermentaciones Industriales (CINDEFI, CCT La Plata - CONICET, UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina.

Although arsenic (As) is recognized as a toxic element for living species, some microorganisms have the ability to tolerate and transform it; recent studies have proposed to take advantage of such capacity to develop sustainable bioremediation strategies. In this study, we evaluated the adaptation to increasing concentrations of As(III) and As(V) of three metabolically different microbial cultures (heterotrophic, autotrophic-acidophilic, and anaerobic) obtained from a sample with low-soluble As content from the Copahue geothermal system. At the end of the adaptation process, the heterotrophic culture was able to grow at 20 mM and 450 mM of As(III) and As(V), respectively; the autotrophic-acidophilic culture showed tolerance to 15 mM of As(III) and 150 mM of As(V), whereas the anaerobic culture only developed in As(V) at concentrations up to 50 mM. The most tolerant consortia were characterized by their growth performance, complexity, and the presence of genes related to As metabolism and resistance. Regarding the consortia complexity, the predominant genera identified were: Paenibacillus in both heterotrophic consortia, Acidithiobacillus in the autotrophic-acidophilic consortium tolerant to As(III), Acidiphilium in the autotrophic-acidophilic consortium tolerant to As(V), and Thiomonas and Clostridium in the anaerobic consortium. This study is the first report of As tolerance microorganisms obtained from Copahue and reasserts the versatility and flexibility of the community of this natural extreme environment; also, it opens the door to the study of possible uses of these consortia in the design of biotechnological processes where the As concentration may fluctuate.
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http://dx.doi.org/10.1002/jobm.201800628DOI Listing
July 2019

Domestication of Local Microbial Consortia for Efficient Recovery of Gold Through Top-Down Selection in Airlift Bioreactors.

Front Microbiol 2019 30;10:60. Epub 2019 Jan 30.

Microbial Ecophysiology Laboratory, Fundación Ciencia & Vida, Santiago, Chile.

Extreme acidophiles play central roles in the geochemical cycling of diverse elements in low pH environments. This has been harnessed in biotechnologies such as biomining, where microorganisms facilitate the recovery of economically important metals such as gold. By generating both extreme acidity and a chemical oxidant (ferric iron) many species of prokaryotes that thrive in low pH environments not only catalyze mineral dissolution but also trigger both community and individual level adaptive changes. These changes vary in extent and direction depending on the ore mineralogy, water availability and local climate. The use of indigenous versus introduced microbial consortia in biomining practices is still a matter of debate. Yet, indigenous microbial consortia colonizing sulfidic ores that have been domesticated, i.e., selected for their ability to survive under specific polyextreme conditions, are claimed to outperform un-adapted foreign consortia. Despite this, little is known on the domestication of acidic microbial communities and the changes elicited in their members. In this study, high resolution targeted metagenomic techniques were used to analyze the changes occurring in the community structure of local microbial consortia acclimated to growing under extreme acidic conditions and adapted to endure the conditions imposed by the target mineral during biooxidation of a gold concentrate in an airlift reactor over a period of 2 years. The results indicated that operative conditions evolving through biooxidation of the mineral concentrate exerted strong selective pressures that, early on, purge biodiversity in favor of a few spp. over other iron oxidizing acidophiles. Metagenomic analysis of the domesticated consortium present at the end of the adaptation experiment enabled reconstruction of the RVS1-MAG, a novel representative of from the Andacollo gold mineral district. Comparative genomic analysis performed with this genome draft revealed a net enrichment of gene functions related to heavy metal transport and stress management that are likely to play a significant role in adaptation and survival to adverse conditions experienced by these acidophiles during growth in presence of gold concentrates.
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http://dx.doi.org/10.3389/fmicb.2019.00060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6363673PMC
January 2019

Combined strategy for removal of Reactive Black 5 by biomass sorption on Macrocystis pyrifera and zerovalent iron nanoparticles.

J Environ Manage 2018 Feb 12;207:70-79. Epub 2017 Dec 12.

Gerencia Química, Comisión Nacional de Energía Atómica, CONICET, Av. Gral. Paz 1499, 1650, San Martín, Prov. de Buenos Aires, Argentina; Instituto de Investigación e Ingeniería Ambiental, Universidad Nacional de Gral. San Martín, Campus Miguelete, Av. 25 de Mayo y Francia, 1650, San Martín, Prov. de Buenos Aires, Argentina. Electronic address:

Reactive Black 5, RB5, has been used as a model azo dye to evaluate the removal efficiency of sorption on Macrocystis pyrifera biomass (Mpyr) and commercial zerovalent iron nanoparticles (nZVI) in individual and combined treatments. The best conditions for the treatment with the isolated materials were first determined, and then, in series and combined treatments were performed under these conditions, achieving removal efficiencies higher than 80% of the initial dye concentration. Strengths and weaknesses of all removal strategies (individual, in series and combined) are analyzed regarding the application on real effluents. Mpyr efficiently adsorbed RB5, but also increased the total organic content by partial dissolution of components of the algal biomass. Removal experiments with commercial nZVI were also efficient but liberated Fe to the solution, and sulfanilic acid was observed after the treatment as a product of RB5 degradation. In contrast, after the Mpyr treatment, no sulfanilic acid was detected, suggesting that sulfanilic acid is efficiently adsorbed by the biomass. The best condition was the integrated use of Mpyr and nZVI, with a remarkable removal efficiency (69-80%) obtained after only 1 h of treatment. Finally, nZVI were successfully immobilized in Mpyr, and the hybrid material was used to remove RB5 in continuous flow experiments at pH 3, obtaining a removal capacity of 39.9 mg RB5 g after a total processed volume of 630 mL of [RB5] = 100 mg L.
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http://dx.doi.org/10.1016/j.jenvman.2017.11.002DOI Listing
February 2018

Effects of Physiochemical Factors on Prokaryotic Biodiversity in Malaysian Circumneutral Hot Springs.

Front Microbiol 2017 6;8:1252. Epub 2017 Jul 6.

Faculty of Biosciences and Medical Engineering, Universiti Teknologi MalaysiaSkudai, Malaysia.

Malaysia has a great number of hot springs, especially along the flank of the Banjaran Titiwangsa mountain range. Biological studies of the Malaysian hot springs are rare because of the lack of comprehensive information on their microbial communities. In this study, we report a cultivation-independent census to describe microbial communities in six hot springs. The Ulu Slim (US), Sungai Klah (SK), Dusun Tua (DT), Sungai Serai (SS), Semenyih (SE), and Ayer Hangat (AH) hot springs exhibit circumneutral pH with temperatures ranging from 43°C to 90°C. Genomic DNA was extracted from environmental samples and the V3-V4 hypervariable regions of 16S rRNA genes were amplified, sequenced, and analyzed. High-throughput sequencing analysis showed that microbial richness was high in all samples as indicated by the detection of 6,334-26,244 operational taxonomy units. In total, 59, 61, 72, 73, 65, and 52 bacterial phyla were identified in the US, SK, DT, SS, SE, and AH hot springs, respectively. Generally, Firmicutes and Proteobacteria dominated the bacterial communities in all hot springs. Archaeal communities mainly consisted of Crenarchaeota, Euryarchaeota, and Parvarchaeota. In beta diversity analysis, the hot spring microbial memberships were clustered primarily on the basis of temperature and salinity. Canonical correlation analysis to assess the relationship between the microbial communities and physicochemical variables revealed that diversity patterns were best explained by a combination of physicochemical variables, rather than by individual abiotic variables such as temperature and salinity.
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http://dx.doi.org/10.3389/fmicb.2017.01252DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5498555PMC
July 2017

Genome analysis of the thermoacidophilic archaeon Acidianus copahuensis focusing on the metabolisms associated to biomining activities.

BMC Genomics 2017 06 6;18(1):445. Epub 2017 Jun 6.

CINDEFI (CCT La Plata-CONICET, UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calle 47 y 115, 1900, La Plata, Argentina.

Background: Several archaeal species from the order Sulfolobales are interesting from the biotechnological point of view due to their biomining capacities. Within this group, the genus Acidianus contains four biomining species (from ten known Acidianus species), but none of these have their genome sequenced. To get insights into the genetic potential and metabolic pathways involved in the biomining activity of this group, we sequenced the genome of Acidianus copahuensis ALE1 strain, a novel thermoacidophilic crenarchaeon (optimum growth: 75 °C, pH 3) isolated from the volcanic geothermal area of Copahue at Neuquén province in Argentina. Previous experimental characterization of A. copahuensis revealed a high biomining potential, exhibited as high oxidation activity of sulfur and sulfur compounds, ferrous iron and sulfide minerals (e.g.: pyrite). This strain is also autotrophic and tolerant to heavy metals, thus, it can grow under adverse conditions for most forms of life with a low nutrient demand, conditions that are commonly found in mining environments.

Results: In this work we analyzed the genome of Acidianus copahuensis and describe the genetic pathways involved in biomining processes. We identified the enzymes that are most likely involved in growth on sulfur and ferrous iron oxidation as well as those involved in autotrophic carbon fixation. We also found that A. copahuensis genome gathers different features that are only present in particular lineages or species from the order Sulfolobales, some of which are involved in biomining. We found that although most of its genes (81%) were found in at least one other Sulfolobales species, it is not specifically closer to any particular species (60-70% of proteins shared with each of them). Although almost one fifth of A. copahuensis proteins are not found in any other Sulfolobales species, most of them corresponded to hypothetical proteins from uncharacterized metabolisms.

Conclusion: In this work we identified the genes responsible for the biomining metabolisms that we have previously observed experimentally. We provide a landscape of the metabolic potentials of this strain in the context of Sulfolobales and propose various pathways and cellular processes not yet fully understood that can use A. copahuensis as an experimental model to further understand the fascinating biology of thermoacidophilic biomining archaea.
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http://dx.doi.org/10.1186/s12864-017-3828-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5461723PMC
June 2017

Editorial: Genetics, Genomics and -Omics of Thermophiles.

Front Microbiol 2017 3;8:560. Epub 2017 Apr 3.

Department of Biology, Portland State UniversityPortland, OR, USA.

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http://dx.doi.org/10.3389/fmicb.2017.00560DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5376578PMC
April 2017

Thermophilic microorganisms in biomining.

World J Microbiol Biotechnol 2016 Nov 15;32(11):179. Epub 2016 Sep 15.

CINDEFI (CCT LA PLATA-CONICET, UNLP), Facultad de Ciencias Exactas (UNLP), 47 y 115, (1900) La Plata, Buenos Aires, Argentina.

Biomining is an applied biotechnology for mineral processing and metal extraction from ores and concentrates. This alternative technology for recovering metals involves the hydrometallurgical processes known as bioleaching and biooxidation where the metal is directly solubilized or released from the matrix for further solubilization, respectively. Several commercial applications of biomining can be found around the world to recover mainly copper and gold but also other metals; most of them are operating at temperatures below 40-50 °C using mesophilic and moderate thermophilic microorganisms. Although biomining offers an economically viable and cleaner option, its share of the world´s production of metals has not grown as much as it was expected, mainly considering that due to environmental restrictions in many countries smelting and roasting technologies are being eliminated. The slow rate of biomining processes is for sure the main reason of their poor implementation. In this scenario the use of thermophiles could be advantageous because higher operational temperature would increase the rate of the process and in addition it would eliminate the energy input for cooling the system (bioleaching reactions are exothermic causing a serious temperature increase in bioreactors and inside heaps that adversely affects most of the mesophilic microorganisms) and it would decrease the passivation of mineral surfaces. In the last few years many thermophilic bacteria and archaea have been isolated, characterized, and even used for extracting metals. This paper reviews the current status of biomining using thermophiles, describes the main characteristics of thermophilic biominers and discusses the future for this biotechnology.
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http://dx.doi.org/10.1007/s11274-016-2140-2DOI Listing
November 2016

Draft Genome Sequence of the Sulfate-Reducing Bacterium Desulfotomaculum copahuensis Strain CINDEFI1 Isolated from the Geothermal Copahue System, Neuquén, Argentina.

Genome Announc 2016 Aug 18;4(4). Epub 2016 Aug 18.

CINDEFI (CCT, La Plata-CONICET, UNLP), Facultad de Ciencias Exactas, Universidad Nacional de la Plata, La Plata, Argentina.

Desulfotomaculum copahuensis strain CINDEFI1 is a novel spore-forming sulfate-reducing bacterium isolated from the Copahue volcano area, Argentina. Here, we present its draft genome in which we found genes related with the anaerobic respiration of sulfur compounds similar to those present in the Copahue environment.
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http://dx.doi.org/10.1128/genomeA.00870-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4991723PMC
August 2016

Biofilm formation and interspecies interactions in mixed cultures of thermo-acidophilic archaea Acidianus spp. and Sulfolobus metallicus.

Res Microbiol 2016 Sep 5;167(7):604-12. Epub 2016 Jul 5.

Biofilm Centre, Aquatische Biotechnologie, Universität Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany; Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Department of Hydraulic and Environmental Engineering, School of Engineering, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 782-0436 Santiago, Chile. Electronic address:

The understanding of biofilm formation by bioleaching microorganisms is of great importance for influencing mineral dissolution rates and to prevent acid mine drainage (AMD). Thermo-acidophilic archaea such as Acidianus, Sulfolobus and Metallosphaera are of special interest due to their ability to perform leaching at high temperatures, thereby enhancing leaching rates. In this work, leaching experiments and visualization by microscopy of cell attachment and biofilm formation patterns of the crenarchaeotes Sulfolobus metallicus DSM 6482(T) and the Acidianus isolates DSM 29038 and DSM 29099 in pure and mixed cultures on sulfur or pyrite were studied. Confocal laser scanning microscopy (CLSM) combined with fluorescent dyes as well as fluorescently labeled lectins were used to visualize different components (e.g. DNA, proteins or glycoconjugates) of the aforementioned species. The data indicate that cell attachment and the subsequently formed biofilms were species- and substrate-dependent. Pyrite leaching experiments coupled with pre-colonization and further inoculation with a second species suggest that both species may negatively influence each other during pyrite leaching with respect to initial attachment and pyrite dissolution rates. In addition, the investigation of binary biofilms on pyrite showed that both species were heterogeneously distributed on pyrite surfaces in the form of individual cells or microcolonies. Physical contact between the two species seems to occur, as revealed by specific lectins able to specifically bind single species within mixed cultures.
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http://dx.doi.org/10.1016/j.resmic.2016.06.005DOI Listing
September 2016

EXAFS and DFT study of the cadmium and lead adsorption on modified silica nanoparticles.

Spectrochim Acta A Mol Biomol Spectrosc 2015 Dec 24;151:156-63. Epub 2015 Jun 24.

Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CCT-La Plata-CONICET, Universidad Nacional de La Plata, Diag 113 y 64, 1900 La Plata, Argentina. Electronic address:

Silica nanoparticles of 7 nm diameter were modified with (3-aminopropyl) triethoxysilane (APTES) and characterized by CP-MAS (13)C and (29)Si NMR, FTIR, zeta potential measurements, and thermogravimetry. The particles were shown to sorb successfully divalent lead and cadmium ions from aqueous solution. Lead complexation with these silica nanoparticles was clearly confirmed by EXAFS (Extended X-ray Absorption Fine Structure) with synchrotron light measurements. Predicted Pb-N and Pb-C distances obtained from quantum-chemical calculations are in very good agreement with the EXAFS determinations. The calculations also support the higher APTES affinity for Pb(2+) compared to Cd(2+).
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http://dx.doi.org/10.1016/j.saa.2015.06.093DOI Listing
December 2015

Thermophiles in the genomic era: Biodiversity, science, and applications.

Biotechnol Adv 2015 Nov 22;33(6 Pt 1):633-47. Epub 2015 Apr 22.

Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Malaysia. Electronic address:

Thermophiles and hyperthermophiles are present in various regions of the Earth, including volcanic environments, hot springs, mud pots, fumaroles, geysers, coastal thermal springs, and even deep-sea hydrothermal vents. They are also found in man-made environments, such as heated compost facilities, reactors, and spray dryers. Thermophiles, hyperthermophiles, and their bioproducts facilitate various industrial, agricultural, and medicinal applications and offer potential solutions to environmental damages and the demand for biofuels. Intensified efforts to sequence the entire genome of hyperthermophiles and thermophiles are increasing rapidly, as evidenced by the fact that over 120 complete genome sequences of the hyperthermophiles Aquificae, Thermotogae, Crenarchaeota, and Euryarchaeota are now available. In this review, we summarise the major current applications of thermophiles and thermozymes. In addition, emphasis is placed on recent progress in understanding the biodiversity, genomes, transcriptomes, metagenomes, and single-cell sequencing of thermophiles in the genomic era.
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http://dx.doi.org/10.1016/j.biotechadv.2015.04.007DOI Listing
November 2015

Comparison of the microbial communities of hot springs waters and the microbial biofilms in the acidic geothermal area of Copahue (Neuquén, Argentina).

Extremophiles 2015 Mar 21;19(2):437-50. Epub 2015 Jan 21.

CINDEFI (CCT La Plata-CONICET, UNLP), calle 50 entre 115 y 116 N° 227 La Plata, Buenos Aires, Argentina,

Copahue is a natural geothermal field (Neuquén province, Argentina) dominated by the Copahue volcano. As a consequence of the sustained volcanic activity, Copahue presents many acidic pools, hot springs and solfataras with different temperature and pH conditions that influence their microbial diversity. The occurrence of microbial biofilms was observed on the surrounding rocks and the borders of the ponds, where water movements and thermal activity are less intense. Microbial biofilms are particular ecological niches within geothermal environments; they present different geochemical conditions from that found in the water of the ponds and hot springs which is reflected in different microbial community structure. The aim of this study is to compare microbial community diversity in the water of ponds and hot springs and in microbial biofilms in the Copahue geothermal field, with particular emphasis on Cyanobacteria and other photosynthetic species that have not been detected before in Copahue. In this study, we report the presence of Cyanobacteria, Chloroflexi and chloroplasts of eukaryotes in the microbial biofilms not detected in the water of the ponds. On the other hand, acidophilic bacteria, the predominant species in the water of moderate temperature ponds, are almost absent in the microbial biofilms in spite of having in some cases similar temperature conditions. Species affiliated with Sulfolobales in the Archaea domain are the predominant microorganism in high temperature ponds and were also detected in the microbial biofilms.
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http://dx.doi.org/10.1007/s00792-015-0729-2DOI Listing
March 2015

Copahue Geothermal System: A Volcanic Environment with Rich Extreme Prokaryotic Biodiversity.

Microorganisms 2015 Jul 8;3(3):344-63. Epub 2015 Jul 8.

CINDEFI (CCT La Plata-CONICET, Facultad de Ciencias Exactas-UNLP), calle 50 entre 115 y 116 N° 227 La Plata, Buenos Aires B8508, Argentina.

The Copahue geothermal system is a natural extreme environment located at the northern end of the Cordillera de los Andes in Neuquén province in Argentina. The geochemistry and consequently the biodiversity of the area are dominated by the activity of the Copahue volcano. The main characteristic of Copahue is the extreme acidity of its aquatic environments; ponds and hot springs of moderate and high temperature as well as Río Agrio. In spite of being an apparently hostile location, the prokaryotic biodiversity detected by molecular ecology techniques as well as cultivation shows a rich and diverse environment dominated by acidophilic, sulphur oxidising bacteria or archaea, depending on the conditions of the particular niche studied. In microbial biofilms, found in the borders of the ponds where thermal activity is less intense, the species found are completely different, with a high presence of cyanobacteria and other photosynthetic species. Our results, collected during more than 10 years of work in Copahue, have enabled us to outline geomicrobiological models for the different environments found in the ponds and Río Agrio. Besides, Copahue seems to be the habitat of novel, not yet characterised autochthonous species, especially in the domain Archaea.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5023244PMC
http://dx.doi.org/10.3390/microorganisms3030344DOI Listing
July 2015

Archaeal and bacterial diversity in five different hydrothermal ponds in the Copahue region in Argentina.

Syst Appl Microbiol 2014 Sep 14;37(6):429-41. Epub 2014 Jul 14.

CINDEFI (CCT La Plata-CONICET, UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calle 47 y 115, 1900 La Plata, Argentina.

Copahue is an acidic geothermal volcanic region in the northwest corner of Neuquén Province, Argentina. In the area, there are various ponds, pools and hot springs with different temperatures, pH values and levels of anthropogenic influence. In this study, the prokaryotic biodiversity of five representative ponds was studied by using two complementary molecular ecology techniques: phylogenetic analysis of 16S rRNA bacterial and archaeal genes and FISH (or CARD-FISH) for quantitative estimation of biodiversity. The results, supported by multivariate statistical analysis, showed that the biodiversity in Copahue ponds seemed to be determined by temperature. High temperature ponds were dominated by archaea, mainly apparently novel representatives from the orders Sulfolobales and Thermoplasmatales that had no close cultivated relatives. By contrast, moderate temperature ponds were colonised by well-characterised sulphur-oxidising bacteria related to acidic environments, such as other geothermal sites or acid mine drainage, and archaea were absent. By combining the biodiversity results from this study and the reported physicochemical features of Copahue, a preliminary model of the possible biogeochemical interaction was outlined for moderate and high temperature ponds.
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http://dx.doi.org/10.1016/j.syapm.2014.05.012DOI Listing
September 2014

Draft Genome Sequence of the Novel Thermoacidophilic Archaeon Acidianus copahuensis Strain ALE1, Isolated from the Copahue Volcanic Area in Neuquen, Argentina.

Genome Announc 2014 May 8;2(3). Epub 2014 May 8.

CINDEFI (CCT La Plata-CONICET, UNLP), Facultad de Ciencias Exactas, Universidad Nacional de la Plata, La Plata, Argentina.

Acidianus copahuensis is a recently characterized thermoacidophilic archaeon isolated from the Copahue volcanic area in Argentina. Here, we present its draft genome sequence, in which we found genes involved in key metabolic pathways for developing under Copahue's extreme environmental conditions, such as sulfur and iron oxidation, carbon fixation, and metal tolerance.
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http://dx.doi.org/10.1128/genomeA.00259-14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4014679PMC
May 2014

Physiologic versatility and growth flexibility as the main characteristics of a novel thermoacidophilic Acidianus strain isolated from Copahue geothermal area in Argentina.

Microb Ecol 2013 Feb 3;65(2):336-46. Epub 2012 Oct 3.

IDEPA (CCT Comahue-CONICET-UNCo), Departamento Química, Facultad de Ingeniería, Universidad Nacional del Comahue, Buenos Aires, Neuquén, Argentina.

A novel thermoacidophilic archaeal strain has been isolated from three geothermal acidic hot springs in Copahue, Argentina. One of the most striking characteristic of ALE1 isolate is its metabolic versatility. It grows on sulphur, tetrathionate, iron (II) and sucrose under aerobic conditions, but it can also develop under anaerobic conditions using iron (III) or sulphur as electron acceptors and sulphur or hydrogen as electron donors autotrophically. A temperature of 75 °C and a pH between 2.5 and 3.0 are strain ALE1 optimal growth conditions, but it is able to oxidise iron (II) even at pH 1.0. Cells are irregular cocci surrounded by a regularly arrayed glycoprotein layer (S-layer). Phylogenetic analysis shows that strain ALE1 belongs to the family Sulfolobaceae in the class Thermoprotei, within the phylum Crenarchaeota. Based on 16S rRNA gene sequence similarity on NCBI database, ALE1 does not have closely related relatives, neither in culture nor uncultured, which is more surprising. Its closest related species are strains of Acidianus hospitalis (91 % of sequence similarity), Acidianus infernus (90 %), Acidianus ambivalens (90 %) and Acidianus manzanensis (90 %). Its DNA base composition of 34.5 % mol C + G is higher than that reported for other Acidianus species. Considering physiological and phylogenetic characteristics of strain ALE1, we considered it to represent a novel species of the genus Acidianus (candidatus "Acidianus copahuensis"). The aim of this study is to physiologically characterise this novel archaea in order to understand its role in iron and sulphur geochemical cycles in the Copahue geothermal area and to evaluate its potential applications in bioleaching and biooxidation.
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http://dx.doi.org/10.1007/s00248-012-0129-4DOI Listing
February 2013

Biosorption of mercury by Macrocystis pyrifera and Undaria pinnatifida: influence of zinc, cadmium and nickel.

J Environ Sci (China) 2011 ;23(11):1778-86

Centro de Investigación y Desarrollo en Fermentaciones Industriales, CINDEFI (CCT La Plata-CONICET, UNLP), Facultad de Ciencias Exactas, 50 y 115, (1900) La Plata, Argentina.

This study investigated the adsorption of Hg(II) on Macrocystis pyrifera and Undaria pinnatifida in monometallic system in the presence of Zn(II), Cd(II) and Ni(II). The two biosorbents reached the same maximum sorption capacity (q(m) = 0.8 mmol/g) for mercury. U. pinnatifida showed a greater affinity (given by the coefficient b of the Langmuir equation) for mercury compared to M. pyrifera (4.4 versus 2.7 L/mmol). Mercury uptake was significantly reduced (by more than 50%) in the presence of competitor heavy metals such as Zn(II), Cd(II) and Ni(II). Samples analysis using an environmental scanning electron microscopy equipped with an energy dispersive X-ray microanalysis showed that mercury was heterogeneously adsorbed on the surface of both biomaterials, while the other heavy metals were homogeneous distributed. The analysis of biosorbents by Fourier transform infrared spectrometry indicated that Hg(II) binding occurred on S = O (sulfonate) and N-H (amine) functional groups.
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http://dx.doi.org/10.1016/s1001-0742(10)60650-xDOI Listing
April 2012

Dynamics of microbial community during bioremediation of phenanthrene and chromium(VI)-contaminated soil microcosms.

Biodegradation 2009 Feb 5;20(1):95-107. Epub 2008 Jul 5.

Centro de Investigación y Desarrollo en Fermentaciones Industriales, CINDEFI (UNLP, CCT-La Plata, CONICET), La Plata, Buenos Aires, Argentina.

The combined effect of phenanthrene and Cr(VI) on soil microbial activity, community composition and on the efficiency of bioremediation processes has been studied. Biometer flask systems and soil microcosm systems contaminated with 2,000 mg of phenanthrene per kg of dry soil and different Cr(VI) concentrations were investigated. Temperature, soil moisture and oxygen availability were controlled to support bioremediation. Cr(VI) inhibited the phenanthrene mineralization (CO(2) production) and cultivable PAH degrading bacteria at levels of 500-2,600 mg kg(-1). In the bioremediation experiments in soil microcosms the degradation of phenanthrene, the dehydrogenase activity and the increase in PAH degrading bacteria counts were retarded by the presence of Cr(VI) at all studied concentrations (25, 50 and 100 mg kg(-1)). These negative effects did not show a correlation with Cr(VI) concentration. Whereas the presence of Cr(VI) had a negative effect on the phenanthrene elimination rate, co-contamination with phenanthrene reduced the residual Cr(VI) concentration in the water exchangeable Cr(VI) fraction (WEF) in comparison with the soil microcosm contaminated only with Cr(VI). Clear differences were found between the denaturing gradient gel electrophoresis (DGGE) patterns of each soil microcosm, showing that the presence of different Cr(VI) concentrations did modulate the community response to phenanthrene and caused perdurable changes in the structure of the microbial soil community.
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http://dx.doi.org/10.1007/s10532-008-9203-5DOI Listing
February 2009

Bacterial removal of chromium (VI) and (III) in a continuous system.

Biodegradation 2007 Aug 8;18(4):505-13. Epub 2006 Nov 8.

Department of Chemical Engineering, Food Technology and Environmental Technologies, University of Cadiz, Puerto Real 11510, Spain.

The capacity of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans to reduce different concentrations of hexavalent chromium in shake flask cultures has been investigated. A. ferrooxidans reduces 100% of chromium (VI) at concentrations of 1, 2.5 and 5 ppm, but in the presence of 10 ppm only 42.9% of chromium (VI) was reduced after 11 days of incubation. A. thiooxidans showed a lower capacity to reduce this ion and total reduction of chromium (VI) was only obtained for concentrations of 1 and 2.5 ppm, whereas 64.7% and 30.5% was reached for 5 and 10 ppm, respectively, after 11 days. A continuous flow mode system was subsequently investigated, in which A. thiooxidans was immobilized on elemental sulphur and the acidic medium obtained was employed to solubilize chromium (III) and to reduce chromium (VI) present in a real electroplating waste [30% of chromium (III) and 0.1% of chromium (VI)]. The system enabled the reduction of 92.7% of hexavalent chromium and represents a promising way to treat this type of waste in the industry.
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http://dx.doi.org/10.1007/s10532-006-9083-5DOI Listing
August 2007