Artículos de revistas
Community of thermoacidophilic and arsenic resistant microorganisms isolated from a deep profile of mine heaps
Autor
J SERGIO CASAS FLORES
ELIDA YAZMIN GOMEZ RODRIGUEZ
JESSICA VIRIDIANA GARCIA MEZA
Institución
Resumen
"Soluble arsenic (As) in acidic feed solution may inhibit the copper (Cu) bioleaching process within mine heaps. To clarify the effect of soluble arsenic on the live biomass and bioxidative activity in heaps, toxicological assays were performed using a synthetic feed solution given by a mine company. The microorganisms had previously been isolated from two heap samples at up to 66 m depth, and cultured using specific media for chemolithotrophic acidophiles (pH 1-2) and moderate thermophiles (48 degrees C), for arsenic tolerance assay. The four media with the highest biomass were selected to assay As-resistance; one culture (Q63h) was chosen to assay biooxidative activity, using a heap sample that contained chalcopyrite and covellite. We found that 0.5 g/L of As does not affect living biomass or biooxidative activity on Cu sulfides, but it dissolves Cu, while As precipitates as arsenic acid (H3AsO4 center dot 1/2H(2)O). The arsenic tolerant community, as identified by 16S rDNA gene sequence analysis, was composed of three main metabolic groups: chemolithotrophs (Leptospirillum, Sulfobacillus); chemolithoheterotrophs and organoheterotrophs as Acidovorax temperans, Pseudomonas alcaligenes, P. mendocina and Sphingomonas spp. Leptospirillum spp. and S. thermosulfidooxidans were the dominant taxa in the Q63-66 cultures from the deepest sample of the oldest, highest-temperature heap. The results indicated arsenic resistance in the microbial community, therefore specific primers were used to amplify ars (arsenic resistance system), aio (arsenite oxidase), or arr (arsenate respiratory reduction) genes from total sample DNA. Presence of arsB genes in S. thermosulfidooxidans in the Q63-66 cultures permits H3AsO4-As(V) detoxification and strengthens the community's response to As."
Ítems relacionados
Mostrando ítems relacionados por Título, autor o materia.
-
Compendio de innovaciones socioambientales en la frontera sur de México
Adriana Quiroga -
Caminar el cafetal: perspectivas socioambientales del café y su gente
Eduardo Bello Baltazar; Lorena Soto_Pinto; Graciela Huerta_Palacios; Jaime Gomez -
Material de empaque para biofiltración con base en poliuretano modificado con almidón, metodos para la manufactura del mismo y sistema de biofiltración
OLGA BRIGIDA GUTIERREZ ACOSTA; VLADIMIR ALONSO ESCOBAR BARRIOS; SONIA LORENA ARRIAGA GARCIA