Mercury Resistance in Bacterial Strains Isolated from Tailing Ponds in a Gold Mining Area Near El Callao (Bolívar State, Venezuela)

Ball, María M.; Carrero, Pablo; Castro, David J.; Yarzábal, Luis Andrés

doi:10.1007/s00284-006-0347-4

Cited by 33 publications

(15 citation statements)

References 16 publications

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“…In particular, secreted exopolysaccharides have been recognized for several decades as important contributors to metal biosorption by microorganisms (13,36). The strains selected here displayed MICs ranging from 20 to 100 M in LB medium and from 15 to 30 M in PB medium, ranges typical for mercury-tolerant or -resistant bacteria (8,51). The metal sequestration capacities of live bacterial biomass were about 1 to 2 mg per g (dry weight) of bacteria.…”

Section: Discussionmentioning

confidence: 96%

Isolation and Characterization of Environmental Bacteria Capable of Extracellular Biosorption of Mercury

François

Lombard

Guigner

et al. 2012

Appl Environ Microbiol

196

102

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Accumulation of toxic metals in the environment represents a public health and wildlife concern. Bacteria resistant to toxic metals constitute an attractive biomass for the development of systems to decontaminate soils, sediments, or waters. In particular, biosorption of metals within the bacterial cell wall or secreted extracellular polymeric substances (EPS) is an emerging process for the bioremediation of contaminated water. Here the isolation of bacteria from soil, effluents, and river sediments contaminated with toxic metals permitted the selection of seven bacterial isolates tolerant to mercury and associated with a mucoid phenotype indicative of the production of EPS. Inductively coupled plasma-optical emission spectroscopy and transmission electron microscopy in conjunction with X-ray energy dispersive spectrometry revealed that bacteria incubated in the presence of HgCl 2 sequestered mercury extracellularly as spherical or amorphous deposits. Killed bacterial biomass incubated in the presence of HgCl 2 also generated spherical extracellular mercury deposits, with a sequestration capacity (40 to 120 mg mercury per g [dry weight] of biomass) superior to that of live bacteria (1 to 2 mg mercury per g [dry weight] of biomass). The seven strains were shown to produce EPS, which were characterized by Fourier transform-infrared (FT-IR) spectroscopy and chemical analysis of neutral-carbohydrate, uronic acid, and protein contents. The results highlight the high potential of Hg-tolerant bacteria for applications in the bioremediation of mercury through biosorption onto the biomass surface or secreted EPS.T hroughout the twentieth century, human activities such as mining, chemical industries, and agriculture have yielded high accumulations of toxic metals in the environment. These metals, bioavailable and persistent (33), constitute a major environmental problem, adversely affecting ecosystems and public health (24). Mercury pollution is of real concern because of the high toxicity of the metal and its translocation all along the food chain: mercury is accumulated upward through the aquatic food chain and is transformed to more-toxic organic mercury forms, mainly highly neurotoxic methylmercury (24).Toxic metals are difficult to remove from the environment, since they cannot be chemically or biologically degraded and are ultimately indestructible. Physicochemical remediation of metalpolluted sites, from incineration of soils to chemical precipitation or/and ion-exchange technologies, has been widely used but remains costly and environmentally damaging. Biological approaches based on metal-resistant microorganisms have received a great deal of attention as alternative remediation processes (20,26). The biological methods used currently for mercury removal consist of Hg 2ϩ reduction to volatile metal mercury by bacterial strains harboring the mer resistance operon (1,32,35,48). Live or dead bacterial biomass has also been used for biosorption applications (52), which consist of passive immobilization of metals by th...

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Section: Discussionmentioning

confidence: 96%

Isolation and Characterization of Environmental Bacteria Capable of Extracellular Biosorption of Mercury

François

Lombard

Guigner

et al. 2012

Appl Environ Microbiol

196

102

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“…All tests were performed in 96-multiwell plates with each well being filled with 200 μL of the growth medium. Each well was inoculated with 5 μL of overnight cultures following incubation at 30°C for 48 h. The lowest concentration of mercury at which no visible growth was observed was considered as the minimal inhibitory concentration (MIC) (Ball et al 2007). Uninoculated LB medium served as negative controls, and inoculated LB medium without mercury served as positive controls.…”

Section: Minimal Inhibitory Concentrationsmentioning

confidence: 99%

Detoxification of Mercury by Bacteria Using Crude Glycerol from Biodiesel as a Carbon Source

Giovanella

Costa

Schaffer

et al. 2015

Water Air Soil Pollut

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Bacteria that harbor the mer operon in their genome are able to enzymatically reduce mercury (II) to the volatile form of mercury Hg (0). Detoxification of contaminated waste by using these bacteria may be an alternative to conventional methods for mercury removal. Residual glycerol from the biodiesel industry can be used as a carbon source to accelerate the process. This work shows for the first time the feasibility of using residual glycerol as a carbon source for Hg removal by bacteria prospected from contaminated environments. Eight bacterial isolates were able to remove mercury and degrade glycerol in mineral medium and residual glycerol. Mercury removal was monitored by atomic absorption spectroscopy and glycerol degradation by high performance liquid chromatography. The best results of mercury removal and glycerol degradation were obtained using isolates of Serratia marcescens M25C (85 and 100 %), Klebsiella pneumoniae PLB (90 and 100 %), Klebsiella oxytoca (90 and 100 %), and Arthrobacter sp. U3 (80 and 75 %), with addition of 0.5 g L −1 yeast extract. The Arthrobacter sp. U3 isolate is common in soils and has proven to be a promising candidate for environment applications due to its low pathogenicity and higher Hg removal and glycerol degradation rates.

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“…As placas foram incubadas a 30 ± 2 ºC até o aparecimento das colônias, que foram isoladas conforme características morfológicas. 11,12 Os isolados foram identificados com base no sequenciamento parcial da região 16S ribossomal. Os oligonucleotídeos iniciadores universais utilizados para bactérias foram o 27F (5'-AGATTTGA-TCMTGGCTCAG-3') e 1492R (5'-TACGGYTACCTTGTTAC-GACTT-3'), para a amplificação em PCR.…”

Section: Parte Experimentalunclassified

“…A maioria dos isolados apresentaram uma CIM de 110 mg L -1 para acetato de mercúrio e acima de 170 mg L -1 para a forma inorgânica divalente, assim como observado por outros autores. 12,22,29 O micro-organismo mais resistente (M100B) cresceu na presença de 210 mg L -1 em ambas as formas de mercúrio. Estes resultados concordam com um grupo de pesquisadores, 30 quando micro-organismos termófilos quimiolitotróficos de uma fonte termal com altas concentrações de Hg foram avaliados.…”

Section: Foram Isoladas 8 Bactérias Provenientes Do Lodo E Efluente Lunclassified

Isolamento e seleção de micro-organismos resistentes e capazes de volatilizar mercúrio

Giovanella¹,

Bento²,

Cabral³

et al. 2011

Quím. Nova

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Recebido em 18/2/10; aceito em 10/9/10; publicado na web em 30/11/10 ISOLATION AND SELECTION OF MICROORGANISMS RESISTANT AND ABLE TO VOLATILIZE MERCURY. Mercury (Hg) occurs in the environment as a natural and anthropogenic element, and through the years the accumulation of mercury has affected the integrity of ecosystems and human health. This study presents a screening of microorganisms resistant to organic and inorganic mercury, the determination of the minimum inhibitory concentration of Hg, the estimation of the mercury volatilization by selected microorganisms and the dynamics of volatilization. Eight Gram-negative bacteria resistant to high concentrations of mercury (60 to 210 mg L -1 ) were selected, and these isolates showed ability to volatilize the metal. The dynamics of the volatilization of the Proteus mirabilis M50C demonstrated that in only 4 h of incubation it was possible to volatilize 72% of the mercury present in the culture. The results showed promising application for bioremediation strategies.Keywords: bacterial resistance to mercury; mercury chloride; minimum inhibitory concentration. INTRODUÇÃOO mercúrio ocorre naturalmente no ambiente em diferentes espécies químicas com solubilidade, reatividade e toxicidade distintas, causando diferentes impactos no ecossistema e na saúde do homem. 1 Este metal é raramente encontrado como elemento livre na natureza, estando em baixas concentrações e amplamente distribuído por toda crosta terrestre. As fontes mais importantes para extração de mercúrio são as reservas de minério de cinábrio (HgS), o qual é encontrado em rochas de regiões onde existe atividade vulcânica recente, em fraturas minerais e em áreas próximas de fontes de águas termais. 2 O mercúrio é emitido para o ambiente por inúmeras fontes naturais e antropogênicas, por meio de combinações complexas, envolvendo reações químicas, físicas e biológicas. As fontes antrópicas mais frequentes de mercúrio são as indústrias petroquímicas, eletrônicas, equipamentos de medição, tintas e cloro-soda; além da utilização na extração de ouro e como amálgamas dentárias. 3 Em humanos, os efeitos renais e neurotóxicos devem ser considerados como os mais importantes numa avaliação de risco pela exposição aos compostos de mercúrio inorgânico. Os sinais e sintomas da ação tóxica do mercúrio no sistema nervoso central consistem basicamente em tremores, depressão, insônia, dificuldade para concentração, diminuição da memória e fobias. A exposição ao mercúrio por longos períodos, mesmo em baixas concentrações pode causar danos renais irreversíveis e afetar o sistema imunológico. [4][5][6] A propriedade química mais importante que explica grande parte dos danos biológicos causados pelo mercúrio é a elevada afinidade que este metal possui pelo grupo sulfidrila das proteínas, causando inativação enzimática e desestruturação proteica. Quando o enxofre está presente fazendo a ponte peptídica de proteínas, o mercúrio divalente substitui o átomo de hidrogênio para formar mercaptanos. Desse modo, mesmo em baixas concentraçõ...

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Mercury Resistance in Bacterial Strains Isolated from Tailing Ponds in a Gold Mining Area Near El Callao (Bolívar State, Venezuela)

Cited by 33 publications

References 16 publications

Isolation and Characterization of Environmental Bacteria Capable of Extracellular Biosorption of Mercury

Isolation and Characterization of Environmental Bacteria Capable of Extracellular Biosorption of Mercury

Detoxification of Mercury by Bacteria Using Crude Glycerol from Biodiesel as a Carbon Source

Isolamento e seleção de micro-organismos resistentes e capazes de volatilizar mercúrio

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