RESUMEN
The study evaluated plants with phytoremediation potential that occur spontaneously in an area of copper mining tailings in Southern of Brazil. Eleven plant species were investigated for heavy metal concentrations in its biomass. All species showed copper concentrations greater than 100 mg kg-1, and seven species highlighted for copper concentrations between 321 and 586 mg kg-1 and these species showed Cr concentrations between 25 and 440 mg kg-1. The species S. viarum Dunal and B. trimera Less were highlighted showing the highest concentrations of Cr (586 mg kg-1) and Cu (440 mg kg-1), respectively. Seven species showed Pb phytoextraction potential and four species showed Cu phytostabilization potential. It was concluded that the investigated species are adapted to low nutritional conditions and showed tolerance to heavy metals, mainly Cu, Pb and Cr in its biomass.
Asunto(s)
Metales Pesados , Contaminantes del Suelo , Biodegradación Ambiental , Brasil , Cobre , Minería , Raíces de PlantasRESUMEN
Mining tailing areas may contain metal minerals such as Cu, Pb, Zn, Cr, and Cd at high concentrations and low nutrients for the growth of plants. This kind of conditions of the area, as well as lack of tailing structure, may limit the development of plants on these areas. Thus, the present study determined the metal, macronutrient, and micronutrient concentrations in the tissues of the roots and shoots of the Solanum viarum Dunal species as well as it evaluated the potential use of the plant for phytoremediation of mining tailing areas contaminated with heavy metals. The macronutrients, micronutrients, and heavy metals in the roots and shoots were determined by the digestion method with nitric and perchloric acid (HNO3-HClO4) and quantified by the ICP-OES. In S. viarum, the average concentrations of the metals presented in the dry biomass varied between the shoots and roots, being higher in the roots for metals such as Cu (229 mg kg-1), Zn (232 mg kg-1), Mn (251 mg kg-1), Cr (382 mg kg-1), Ni (178 mg kg-1), Pb (33 mg kg-1), and Ba (1123 mg kg-1). S. viarum indicates the possibility of a potential application in phytoremediation and treatment of areas contaminated with heavy metals.
Asunto(s)
Restauración y Remediación Ambiental/métodos , Metales Pesados/análisis , Minería , Contaminantes del Suelo/análisis , Solanum/química , Biodegradación Ambiental , Biomasa , Brasil , Metales Pesados/farmacocinética , Raíces de Plantas/química , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/metabolismo , Brotes de la Planta/química , Brotes de la Planta/efectos de los fármacos , Brotes de la Planta/metabolismo , Contaminantes del Suelo/farmacocinética , Solanum/efectos de los fármacos , Solanum/metabolismo , Distribución TisularRESUMEN
Aquatic environments are widely affected by anthropogenic activities and efficient remediation of these areas requires detailed studies for each natural ecosystem. This research aimed to evaluate the natural phytoremediation potential of Hydrocotyle ranunculoides L., a floating aquatic macrophyte located in a polluted aquatic environment in South of the Rio Grande do Sul, Brazil. Nutrients such as P, K, Ca, Mg, and S and heavy metals such as Cu, Zn, Fe, Mn, Na, Cd, Cr, Ni, Pb, Al, As, Co, and V content in the roots and shoots of the plants were evaluated through nitric perchloric acid digestion (HNO3-HClO4) methods and quantified by ICP-OES. Bioconcentration factor (BCF), translocation factor (TF), plant effective number (PEN), and potential phytoremoval (mg m-2) were carried out. H. ranunculoides showed a substantial ability for phytoextracting P, Na, and As, since showed ability of uptake these elements from the water and translocate them to the shoots of the plants. H. ranunculoides also showed potential for application in rhizofiltration of Mg, S, Cu, Zn, Fe, Mn, Cd, Cr, Ni, Pb, Al, and V, since exhibited high potential to uptake higher levels in the roots. The highest potential for bioremoval (mg m-2) of the H. ranunculoides was detected for K, Ca, P (recommending thus the use for phytoextraction), Fe, and Al (highly recommended for rhizofiltration). Therefore, this species under study showed high potential for in situ phytoremediation at Santa Bárbara stream, and as a widespread species, it might be tested for phytoremediation in other sites.
Asunto(s)
Centella/crecimiento & desarrollo , Metales Pesados/análisis , Ríos/química , Contaminantes del Suelo/análisis , Contaminantes Químicos del Agua/análisis , Biodegradación Ambiental , Brasil , Centella/química , Raíces de Plantas/química , Raíces de Plantas/crecimiento & desarrolloRESUMEN
High copper concentration is toxic for living organisms including humans. Biosorption is a bioremediation technique that can remove copper and other pollutants from aqueous medium and soils, consequently cleaning the environment. The aim of this study was, therefore, to investigate the influence of different copper compounds (Cu(II) as CuCl2; Cu(II) as CuSO4; and Cu(I) as CuCl) on copper bioreduction and biosorption using four copper-resistant bacteria isolated from the rhizosphere of two plants (Avena sativa and Plantago lanceolata) in aqueous matrix. Copper resistance profile, bioreduction, and biosorption after 48 h of incubation were evaluated. The isolates displayed high copper resistance. However, isolate A1 did not grow very well in the CuCl2 and isolate T5 was less resistant to copper in aqueous solutions amended with CuCl (Cu(I)). The best copper source for copper bioreduction and biosorption was CuSO4 and the isolates removed as much as ten times more copper than in aqueous solutions amended with the other copper compounds. Moreover, Cu(I) did not succumb to biosorption, although the microbes were resistant to aqueous solutions of CuCl. In summary, Cu(II) from CuSO4 was furthermost susceptible to bioreduction and biosorption for all isolates. This is an indication that copper contamination of the environment from the use of CuSO4 as an agrochemical is amenable to bioremediation.
Asunto(s)
Sulfato de Cobre/aislamiento & purificación , Cobre/aislamiento & purificación , Contaminantes Ambientales/aislamiento & purificación , Acinetobacter/genética , Acinetobacter/crecimiento & desarrollo , Acinetobacter/aislamiento & purificación , Adsorción , Avena/microbiología , Biodegradación Ambiental , Biomasa , Farmacorresistencia Bacteriana , Oxidación-Reducción , Raíces de Plantas/microbiología , Plantago/microbiología , Pseudomonas putida/genética , Pseudomonas putida/crecimiento & desarrollo , Pseudomonas putida/aislamiento & purificación , ARN Ribosómico 16S/genética , Rizosfera , Soluciones , Stenotrophomonas maltophilia/genética , Stenotrophomonas maltophilia/crecimiento & desarrollo , Stenotrophomonas maltophilia/aislamiento & purificación , AguaRESUMEN
The use of microorganisms with hydrocarbon degrading capability and biosurfactant producers have emerged as an alternative for sustainable treatment of environmental passives. In this study 45 bacteria were isolated from samples contaminated with petrochemical residues, from which 21 were obtained from Landfarming soil contaminated with oily sludge, 11 were obtained from petrochemical industry effluents and 13 were originated directly from oily sludge. The metabolization capability of different carbon sources, growth capacity and tolerance, biosurfactant production and enzymes detection were determined. A preliminary selection carried out through the analysis of capability for degrading hydrocarbons showed that 22% of the isolates were able to degrade all carbon sources employed. On the other hand, in 36% of the isolates, the degradation of the oily sludge started within 18-48 h. Those isolates were considered as the most efficient ones. Twenty isolates, identified based on partial sequencing of the 16S rRNA gene, were pre-selected. These isolates showed ability for growing in a medium containing 1% of oily sludge as the sole carbon source, tolerance in a medium containing up to 30% of oily sludge, ability for biosurfactant production, and expression of enzymes involved in degradation of aliphatic and aromatic compounds. Five bacteria, identified as Stenotrophomonas acidaminiphila BB5, Bacillus megaterium BB6, Bacillus cibi, Pseudomonas aeruginosa, and Bacillus cereus BS20 were shown to be promising for use as inoculum in bioremediation processes (bioaugmentation) of areas contaminated with petrochemical residues since they can use oily sludge as the sole carbon source and produce biosurfactants.
Asunto(s)
Bacterias/aislamiento & purificación , Bacterias/metabolismo , Biodegradación Ambiental , Contaminantes Ambientales/metabolismo , Hidrocarburos/metabolismo , Microbiología del Suelo , Bacterias/efectos de los fármacos , Bacterias/crecimiento & desarrollo , Medios de Cultivo/química , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Tensoactivos/metabolismoRESUMEN
Long-term copper application in vineyards and copper mining activities cause heavy metal pollution sites. Such sites need remediation to protect soil and water quality. Bioremediation of contaminated areas through bioleaching can help to remove copper ions from the contaminated soils. Thus, the aim of this work was to evaluate the effects of different treatments for copper bioleaching in two diverse copper-contaminated soils (a 40-year-old vineyard and a copper mining waste) and to evaluate the effect on microbial community by applying denaturing gradient gel electrophoresis (DGGE) of 16S ribosomal DNA amplicons and DNA sequence analysis. Several treatments with HCl, H(2)SO(4), and FeSO(4) were evaluated by stimulation of bioleaching of copper in the soils. Treatments and extractions using FeSO(4) and H(2)SO(4) mixture at 30°C displayed more copper leaching than extractions with deionized water at room temperature. Treatment with H(2)SO(4) supported bioleaching of as much as 120 mg kg(-1) of copper from vineyard soil after 115 days of incubation. DGGE analysis of the treatments revealed that some treatments caused greater diversity of microorganisms in the vineyard soil compared to the copper mining waste. Nucleotide Blast of PCR-amplified fragments of 16S rRNA gene bands from DGGE indicated the presence of Rhodobacter sp., Silicibacter sp., Bacillus sp., Paracoccus sp., Pediococcus sp., a Myxococcales, Clostridium sp., Thiomonas sp., a firmicute, Caulobacter vibrioides, Serratia sp., and an actinomycetales in vineyard soil. Contrarily, Sphingomonas was the predominant genus in copper mining waste in most treatments. Paracoccus sp. and Enterobacter sp. were also identified from DGGE bands of the copper mining waste. Paracoccus species is involved in the copper bioleaching by sulfur oxidation system, liberating the copper bounded in the soils and hence promoting copper bioremediation. Results indicate that stimulation of bioleaching with a combination of FeSO(4) and H(2)SO(4) promoted bioleaching in the soils and can be employed ex situ to remediate copper-impacted soils.
Asunto(s)
Cobre/química , Microbiología del Suelo , Suelo/química , Biodegradación Ambiental , ADN Bacteriano/química , Microbiología Industrial , Minería , Filogenia , Reacción en Cadena de la Polimerasa , Calidad del AguaRESUMEN
Copper is a toxic heavy metal widely used to microbial control especially in agriculture. Consequently, high concentrations of copper residues remain in soils selecting copper-resistant organisms. In vineyards, copper is routinely used for fungi control. This work was undertaken to study copper resistance by rhizosphere microorganisms from two plants (Avena sativa L. and Plantago lanceolata L.) common in vineyard soils. Eleven rhizosphere microorganisms were isolated, and four displayed high resistance to copper. The isolates were identified by 16S rRNA gene sequence analysis as Pseudomonas putida (A1), Stenotrophomonas maltophilia (A2) and Acinetobacter sp. (A6), isolated from Avena sativa rhizosphere, and Acinetobacter sp. (T5), isolated from Plantago lanceolata rhizosphere. The isolates displayed high copper resistance in the temperature range from 25°C to 35°C and pH in the range from 5.0 to 9.0. Pseudomonas putida A1 resisted as much as 1,000 mg L(-1) of copper. The isolates showed similar behavior on copper removal from liquid medium, with a bioremoval rate of 30% at 500 mg L(-1) after 24 h of growth. Speciation of copper revealed high copper biotransformation, reducing Cu(II) to Cu(I), capacity. Results indicate that our isolates are potential agents for copper bioremoval and bacterial stimulation of copper biosorption by Avena sativa and Plantago lanceolata.
Asunto(s)
Avena/microbiología , Bacterias/aislamiento & purificación , Cobre/metabolismo , Plantago/microbiología , Bacterias/metabolismo , Biodegradación Ambiental , Concentración de Iones de Hidrógeno , ARN Bacteriano/metabolismo , ARN Ribosómico 16S/metabolismo , Rizosfera , Microbiología del SueloRESUMEN
The biodegradation capacity of aliphatic and aromatic hydrocarbons of petrochemical oily sludge in liquid medium by a bacterial consortium and five pure bacterial cultures was analyzed. Three bacteria isolated from petrochemical oily sludge, identified as Stenotrophomonas acidaminiphila, Bacillus megaterium and Bacillus cibi, and two bacteria isolated from a soil contaminated by petrochemical waste, identified as Pseudomonas aeruginosa and Bacillus cereus demonstrated efficiency in oily sludge degradation when cultivated during 40 days. The bacterial consortium demonstrated an excellent oily sludge degradation capacity, reducing 90.7% of the aliphatic fraction and 51.8% of the aromatic fraction, as well as biosurfactant production capacity, achieving 39.4% reduction of surface tension of the culture medium and an emulsifying activity of 55.1%. The results indicated that the bacterial consortium has potential to be applied in bioremediation of petrochemical oily sludge contaminated environments, favoring the reduction of environmental passives and increasing industrial productivity.
Asunto(s)
Bacterias/metabolismo , Biotecnología/métodos , Aguas del Alcantarillado/microbiología , Bacillus/metabolismo , Bacillus megaterium/metabolismo , Biodegradación Ambiental , Medios de Cultivo/química , Hidrocarburos/química , Concentración de Iones de Hidrógeno , Mutágenos , Aceites , Petróleo/metabolismo , Microbiología del Suelo , Contaminantes del Suelo/metabolismo , Stenotrophomonas/metabolismo , Tensión Superficial , Tensoactivos/química , Temperatura , Factores de TiempoRESUMEN
This study sought to evaluate the potential of perennial peanut (Arachis pintoi) for copper phytoremediation in vineyard soils (Inceptisol and Mollisol) contaminated with copper and copper mining waste. Our results showed high phytomass production of perennial peanut in both vineyard soils. Macronutrient uptakes were not negatively affected by perennial peanut cultivated in all contaminated soils. Plants cultivated in Mollisol showed high copper concentrations in the roots and shoots of 475 and 52 mg kg(-1), respectively. Perennial peanut plants showed low translocation factor values for Cu, although these plants showed high bioaccumulation factor (BCF) for both vineyard soils, Inceptisol and Mollisol, with BCF values of 3.83 and 3.24, respectively, being characterized as a copper hyperaccumulator plant in these soils. Copper phytoextraction from Inceptisol soil was the highest for both roots and entire plant biomass, with more than 800 mg kg(-1) of copper in whole plant. The highest potential copper phytoextraction by perennial peanut was in Inceptisol soil with copper removal of 2,500 g ha(-1). Also, perennial peanut showed high potential for copper phytoremoval in copper mining waste and Mollisol with 1,700 and 1,500 g of copper per hectare, respectively. In addition, perennial peanuts characterized high potential for phytoextraction and phytostabilization of copper in vineyard soils and copper mining waste.
Asunto(s)
Arachis/metabolismo , Biodegradación Ambiental , Cobre/aislamiento & purificación , Minería , Contaminantes del Suelo/aislamiento & purificación , BiomasaRESUMEN
Environmental copper contamination is a serious human health problem. Copper reductase is produced by microorganisms to facilitate copper uptake by ATPases into the cells increasing copper biosorption. This study assessed the reduction of Cu(II) by cell-free extracts of a highly copper-resistant bacterium, Pseudomonas sp. strain NA, isolated from vineyard soil contaminated with copper. Both intact cells and cell-free extract of Pseudomonas sp. strain NA displayed substantial reduction of Cu(II). Intact cells reduced more then 80 mg L(-1) of Cu(II) from medium amended with 200 mg L(-1) of copper after 24 h of incubation. Cell-free extract of the isolate reduced more than 65% of the Cu(II) at initial copper concentration of 200 mg L(-1) after 24 h. Soluble protein production was high at 72 h of incubation at 100 mg L(-1) of copper, with more then 60 µg L(-1) of total soluble protein in cell-free extract recorded. Cu(II) reduction by isolate NA was increased when copper concentration increased for both intact cells and cell-free extract. Results indicate that Pseudomonas sp. strain NA produces copper reductase enzyme as the key mechanism of copper biotransformation.
Asunto(s)
Proteínas Bacterianas/metabolismo , Cobre/metabolismo , Oxidorreductasas/metabolismo , Pseudomonas/enzimología , Pseudomonas/metabolismo , Oxidación-ReducciónRESUMEN
Isolation of soil microorganisms from a landfarming site with a 19-year history of petrochemical residues disposal was carried out. After isolation, the bacteria behavior in mineral medium with 1% commercial gasoline (24% ethanol) was evaluated. Parameters employed for microorganism evaluation and selection of those with the greatest degradation potential were: microbial growth; biosurfactant generation and compound reduction in commercial gasoline. Starting from bacteria that presented the best degradation results, consortiums formed by 4 distinct microorganisms were formed. A microbial growth in the presence of commercial gasoline was observed and, for most of the bacteria, degradations of compounds such as benzene, toluene and xylenes (BTX) as well as biosurfactant production was observed. Ethanol was partially degraded by the bacterial isolates although the data does not allow affirming that it was degraded preferentially to the aromatic hydrocarbons investigated. The analyzed consortiums present an efficiency of 95% to 98% for most of the commercial gasoline compounds and a preferential attack to ethanol under the essay condition was not observed within 72 h.
Asunto(s)
Biodegradación Ambiental , Gasolina/microbiología , Benceno/metabolismo , Etanol/metabolismo , Tolueno/metabolismo , Xilenos/metabolismoRESUMEN
Lack of attention to soil and microbial characteristics that influence PAHs degradation has been a leading cause of failures in isolation of efficient PAH degraders and bioaugumentation processes with microbial consortia. This study compared the classic method of isolation of PAHs-degraders with a modified method employing a pre-enrichment respirometric analysis. The modified enrichment of PAH degrading microorganisms using in vitro microcosm resulted to reduced enrichment period and more efficient PAH-degrading microbial consortia. Results indicate that natural soils with strong heterotrophic microbial activity determined through pre-enrichment analysis, are better suited for the isolation of efficient PAH degrading microorganisms with significant reduction of the enrichment period.
Asunto(s)
Antracenos/metabolismo , Bacterias/aislamiento & purificación , Bacterias/metabolismo , Hidrocarburos Policíclicos Aromáticos/metabolismo , Microbiología del Suelo , Bacterias/genética , Biodegradación Ambiental , ADN Bacteriano/genética , ADN Ribosómico/genética , Datos de Secuencia Molecular , ARN Ribosómico 16S/genética , Contaminantes del Suelo/metabolismoRESUMEN
In this study we evaluated the capacity of a defined microbial consortium (five bacteria: Mycobacterium fortuitum, Bacillus cereus, Microbacterium sp., Gordonia polyisoprenivorans, Microbacteriaceae bacterium, Naphthalene-utilizing bacterium; and a fungus identified as Fusarium oxysporum) isolated from a PAHs contaminated landfarm site to degrade and mineralize different concentrations (0, 250, 500 and 1000 mg kg(-1)) of anthracene, phenanthrene and pyrene in soil. PAHs degradation and mineralization was evaluated by gas chromatography and respirometry, respectively. The microbial consortium degraded on average, 99%, 99% and 96% of the different concentrations of anthracene, phenanthrene and pyrene in the soil, in 70 days, respectively. This consortium mineralized 78%, on average, of the different concentrations of the 3 PAHs in soil after 70 days. Contrarily, the autochthonous soil microbial population showed no substantial mineralization of the PAHs. Bacterial and fungal isolates from the consortium, when inoculated separately to the soil, were less effective in anthracene mineralization compared to the consortium. This signifies synergistic promotion of PAHs mineralization by mixtures of the monoculture isolates (the microbial consortium).
Asunto(s)
Compuestos Policíclicos/metabolismo , Microbiología del Suelo , Contaminantes del Suelo/metabolismoRESUMEN
Iron may enhance polycyclic aromatic hydrocarbons (PAHs) degradation directly by increasing the activity of the enzymes involved in the aerobic biodegradation pathways for hydrocarbons, and indirectly by increasing the PAHs bioavailability due to the stimulation of biosurfactant production. In the present work, the PAH anthracene was used in order to study the effect of different forms and concentrations of iron on its biodegradation and surfactant production by Pseudomonas spp. isolates from a 14-years old petrochemical sludge landfarm site. Among the iron forms, iron nitrate was chosen based on its high solubility and effect on the increase in the growth of the isolate. Iron concentration of 0.1mM was selected as the limit between deficiency and toxicity for isolates growth and anthracene degradation. After 48 days Pseudomonas citronellolis isolate 222A degraded 72% of anthracene related to iron stimulation and surface tension decrease, indicating surfactant production. Pseudomonas aeruginosa isolate 332C was iron-stimulated but did not reduce surface tension while P. aeruginosa isolate 312A exhibited a noniron and surfactant dependence to degrade 72% of anthracene. Isolate 222A showed a direct dependence on iron to stimulate surfactant activity, which probably increased anthracene bioavailability. To our knowledge, this is the first report about the iron effect on anthracene degradation and surfactant production by a Pseudomonas sp. Based on the iron requirement and surfactant activity, the Pseudomonas isolates may be useful for bioremediation of PAHs.
Asunto(s)
Antracenos/metabolismo , Hierro/metabolismo , Pseudomonas/metabolismo , Contaminantes del Suelo/metabolismoRESUMEN
Bioremediation of diesel oil in soil can occur by natural attenuation, or treated by biostimulation or bioaugmentation. In this study we evaluated all three technologies on the degradation of total petroleum hydrocarbons (TPH) in soil. In addition, the number of diesel-degrading microorganisms present and microbial activity as indexed by the dehydrogenase assay were monitored. Soils contaminated with diesel oil in the field were collected from Long Beach, California, USA and Hong Kong, China. After 12 weeks of incubation, all three treatments showed differing effects on the degradation of light (C12-C23) and heavy (C23-C40) fractions of TPH in the soil samples. Bioaugmentation of the Long Beach soil showed the greatest degradation in the light (72.7%) and heavy (75.2%) fractions of TPH. Natural attenuation was more effective than biostimulation (addition of nutrients), most notably in the Hong Kong soil. The greatest microbial activity (dehydrogenase activity) was observed with bioaugmentation of the Long Beach soil (3.3-fold) and upon natural attenuation of the Hong Kong sample (4.0-fold). The number of diesel-degrading microorganisms and heterotrophic population was not influenced by the bioremediation treatments. Soil properties and the indigenous soil microbial population affect the degree of biodegradation; hence detailed site specific characterization studies are needed prior to deciding on the proper bioremediation method.