Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
Adicionar filtros








Intervalo de ano
2.
Braz. j. microbiol ; 47(3): 571-586, July-Sept. 2016. tab, graf
Artigo em Inglês | LILACS | ID: lil-788980

RESUMO

ABSTRACT An analysis of wastewater samples collected from different industrial regions of Egypt demonstrated dangerously high levels of nickel (0.27-31.50 mg L-1), chromium (1.50-7.41 mg L-1) and zinc (1.91-9.74 mg L-1) in the effluents. Alarmingly, these heavy metals are among the most toxic knownones to humans and wildlife. Sixty-nine Actinomycete isolates derived from contaminated sites were evaluated under single, binary, and ternary systems for their biosorption capacity for Ni2+, Cr6+ and Zn2+ from aqueous solutions. The results of the study identified isolates MORSY1948 and MORSY2014 as the most active biosorbents. Phenotypic and chemotypic characterization along with molecular phylogenetic evidence confirmed that the two strains are members of the Nocardiopsis and Nocardia genera, respectively. The results also proved that for both the strains, heavy metal reduction was more efficient with dead rather than live biomass. The affinity of the dead biomass of MORSY1948 strain for Ni2+, Cr6+ and Zn2+ under the optimized pH conditions of 7, 8 and 7, respectively at 40 °C temperature with 0.3% biosorbent dosage was found to be as follows: Ni2+ (87.90%) > Zn2+ (84.15%) > Cr6+ (63.75%). However, the dead biomass of MORSY2014 strain under conditions of pH 8 and 50 °C temperature with 0.3% biosorbent dose exhibited the highest affinity which was as follows: Cr6+ (95.22%) > Ni2+ (93.53%) > Zn2+ (90.37%). All heavy metals under study were found to be removed from aqueous solutions in entirety when the sorbent dosage was increased to 0.4%.


Assuntos
Metais Pesados/metabolismo , Nocardia/classificação , Nocardia/metabolismo , Temperatura , Fatores de Tempo , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , RNA Ribossômico 16S/genética , Biomassa , Metais Pesados/toxicidade , Adsorção , Egito , Águas Residuárias/microbiologia , Concentração de Íons de Hidrogênio , Resíduos Industriais , Nocardia/isolamento & purificação , Nocardia/genética
3.
Artigo em Inglês | IMSEAR | ID: sea-24851

RESUMO

The role of silicon (Si) in metabolism and growth of 22 strains of mycobacteria and 3 strains of nocardiae, which were mostly pathogenic, was studied on Kirchner's medium solidified with sodium metasilicate (KSM) and the C-free solidified metasilicate minimal medium (SMM) consisting of mineral salts only. On KSM, initial growth of mycobacteria appeared to be better, compared with that on Lowenstein-Jensen medium (LJM), although subsequent growth on the former was slower. On SMM lacking C, growth of mycobacteria and nocardiae could be achieved, only after repeated passages. These findings indicate that the mycobacteria and nocardiae are able to utilise Si at least to a limited extent, possibly as an alternative to C, with greater chances of survival.


Assuntos
Meios de Cultura , Mycobacterium/metabolismo , Nocardia/metabolismo , Silício/metabolismo
5.
Indian J Biochem Biophys ; 1980 Oct; 17(5): 387-8
Artigo em Inglês | IMSEAR | ID: sea-29134
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA