RESUMO
The efficiency of co-application of Eisenia fetida and ryegrass was evaluated in a process called earthworm-assisted phytoremediation. Anthracene was used as a model compound for polycyclic aromatic hydrocarbons (PAHs). The experiments were conducted on a loamy soil in greenhouse conditions. At the end of the experiment, the soil samples were analyzed for residual anthracene by HPLC. Results showed that, phytoremediation using ryegrass could remove 81% of anthracene; however, the rate of removal was 92% when E. fetida was applied simultaneously. E. fetida alone could also remove the initial concentration of anthracene by 40%. Although ryegrass itself could remove anthracene significantly, the employment of earthworm, together with plant was more efficient than each of them individually. The application of E. fetida could also enhance the growth parameters of ryegrass significantly. In comparison to the control, the presence of E. fetida increased plant dry weight (7.8%), root length (47%), shoots length (32%), and root volume (12%). The number of live earthworms was also increased in the planted pots, indicating the helpfulness of the plant for survival of the earthworm in the PAH-contaminated soil. Although plant and earthworm use completely different mechanisms for anthracene degradation, they improve efficiency and survival of the three-component-system.
A eficiência da co-aplicação de Eisenia fetida e azevém foi avaliada em um processo denominado fitorremediação assistida por minhocas. O antraceno foi usado como um composto modelo para hidrocarbonetos aromáticos policíclicos (PAHs). Os experimentos foram conduzidos em um solo argiloso em condições de estufa. No final da experiência, as amostras de solo foram analisadas quanto ao antraceno residual por HPLC. Os resultados mostraram que, a fitorremediação com azevém pode remover 81% do antraceno; no entanto, a taxa de remoção foi de 92% quando E. fetida foi aplicada simultaneamente. E. fetida sozinha também foi capaz de remover a concentração inicial de antraceno em 40%. Embora o próprio azevém pudesse remover significativamente o antraceno, o emprego da minhoca, juntamente com a planta, foi mais eficiente do que cada um deles individualmente. A aplicação de E. fetida também pode melhorar significativamente os parâmetros de crescimento do azevém. Em comparação com o controle, a presença de E. fetida aumentou o peso seco da planta (7,8%), o comprimento da raiz (47%), o comprimento da parte aérea (32%) e o volume radicular (12%). O número de minhocas vivas também aumentou nos vasos plantados, indicando a utilidade da planta para a sobrevivência da minhoca no solo contaminado com PAH. Embora plantas e minhocas usem mecanismos completamente diferentes para a degradação do antraceno, eles melhoram a eficiência e a sobrevivência do sistema de três componentes.
Assuntos
Oligoquetos , Biodegradação Ambiental , Antracenos , Lolium , HidrocarbonetosRESUMO
A mesophilic Enterobacter sp. Bn12 producing an alkaline thermostable lipase was isolated from soil in Tehran, Iran. The lipase gene (ELBn12) was identified from a genomic library. Sequence analysis of the DNA fragment revealed an open reading frame of 879 bp encoding a lipase with a molecular mass of 31.3 kDa. The deduced amino acid sequence showed 96% identity with a lipase of Enterobacter sp. Ag1 and the identity of their DNA sequences was 88.9%. ELBn12 belongs to the lipase subfamily I.1 and its catalytic triad consists of Ser82, Asp237 and His259. The lipase was expressed in Escherichia coli (BL21) pLysS and partially purified by anion exchange chromatography. The maximum activity of ELBn12 was obtained at temperature of 60 °C and pH 8.0 towards tricaprylin (C8) and its specific activity was around 2900 U/mg. ELBn12 was stable within a broad pH range from 6.0 to 11.0. The enzyme showed high stability in both polar and nonpolar organic solvents at 50% (v/v). The lipase activity was enhanced in the presence of 10 mM of Ca(2+), Mg(2+) and K(+), while heavy metals (Fe(3+) and Zn(2+)) had strong inhibitory effect. ELBn12 showed high activity in the presence of 1% (w/v) nonionic surfactants, however ionic surfactants inhibited the lipolytic activity. ELBn12 characteristics show that it has a potential to be used in various industrial processes.
Assuntos
Enterobacter/enzimologia , Lipase/isolamento & purificação , Lipase/metabolismo , Sequência de Aminoácidos , Técnicas de Tipagem Bacteriana , Sequência de Bases , Cromatografia por Troca Iônica , Clonagem Molecular , DNA Bacteriano/química , DNA Bacteriano/genética , Enterobacter/classificação , Enterobacter/genética , Enterobacter/isolamento & purificação , Ativadores de Enzimas/análise , Inibidores Enzimáticos/análise , Estabilidade Enzimática , Escherichia coli/genética , Expressão Gênica , Concentração de Íons de Hidrogênio , Irã (Geográfico) , Lipase/química , Lipase/genética , Dados de Sequência Molecular , Peso Molecular , Fases de Leitura Aberta , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Homologia de Sequência do Ácido Nucleico , Microbiologia do Solo , TemperaturaRESUMO
A mesophilic Enterobacter sp. Bn12 producing an alkaline thermostable lipase was isolated from soil in Tehran, Iran. The lipase gene (ELBn12) was identified from a genomic library. Sequence analysis of the DNA fragment revealed an open reading frame of 879 bp encoding a lipase with a molecular mass of 31.3 kDa. The deduced amino acid sequence showed 96% identity with a lipase of Enterobacter sp. Ag1 and the identity of their DNA sequences was 88.9%. ELBn12 belongs to the lipase subfamily I.1 and its catalytic triad consists of Ser82, Asp237 and His259. The lipase was expressed in Escherichia coli (BL21) pLysS and partially purified by anion exchange chromatography. The maximum activity of ELBn12 was obtained at temperature of 60 °C and pH 8.0 towards tricaprylin (C8) and its specific activity was around 2900 U/mg. ELBn12 was stable within a broad pH range from 6.0 to 11.0. The enzyme showed high stability in both polar and nonpolar organic solvents at 50% (v/v). The lipase activity was enhanced in the presence of 10 mM of Ca2+, Mg2+ and K+, while heavy metals (Fe3+ and Zn2+) had strong inhibitory effect. ELBn12 showed high activity in the presence of 1% (w/v) nonionic surfactants, however ionic surfactants inhibited the lipolytic activity. ELBn12 characteristics show that it has a potential to be used in various industrial processes.
Assuntos
Enterobacter/enzimologia , Lipase/isolamento & purificação , Lipase/metabolismo , Sequência de Aminoácidos , Técnicas de Tipagem Bacteriana , Sequência de Bases , Cromatografia por Troca Iônica , Clonagem Molecular , DNA Bacteriano/química , DNA Bacteriano/genética , Estabilidade Enzimática , Enterobacter/classificação , Enterobacter/genética , Enterobacter/isolamento & purificação , Ativadores de Enzimas/análise , Inibidores Enzimáticos/análise , Escherichia coli/genética , Expressão Gênica , Concentração de Íons de Hidrogênio , Irã (Geográfico) , Lipase/química , Lipase/genética , Dados de Sequência Molecular , Peso Molecular , Fases de Leitura Aberta , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Homologia de Sequência do Ácido Nucleico , Microbiologia do Solo , TemperaturaRESUMO
A mesophilic Enterobacter sp. Bn12 producing an alkaline thermostable lipase was isolated from soil in Tehran, Iran. The lipase gene (ELBn12) was identified from a genomic library. Sequence analysis of the DNA fragment revealed an open reading frame of 879 bp encoding a lipase with a molecular mass of 31.3 kDa. The deduced amino acid sequence showed 96% identity with a lipase of Enterobacter sp. Ag1 and the identity of their DNA sequences was 88.9%. ELBn12 belongs to the lipase subfamily I.1 and its catalytic triad consists of Ser82, Asp237 and His259. The lipase was expressed in Escherichia coli (BL21) pLysS and partially purified by anion exchange chromatography. The maximum activity of ELBn12 was obtained at temperature of 60 °C and pH 8.0 towards tricaprylin (C8) and its specific activity was around 2900 U/mg. ELBn12 was stable within a broad pH range from 6.0 to 11.0. The enzyme showed high stability in both polar and nonpolar organic solvents at 50% (v/v). The lipase activity was enhanced in the presence of 10 mM of Ca2+, Mg2+ and K+, while heavy metals (Fe3+ and Zn2+) had strong inhibitory effect. ELBn12 showed high activity in the presence of 1% (w/v) nonionic surfactants, however ionic surfactants inhibited the lipolytic activity. ELBn12 characteristics show that it has a potential to be used in various industrial processes.