Transformación de arsénico por bacterias aisladas de sedimentos enriquecidos con el metaloide

Translated title of the contribution: Arsenic transformation by isolated bacteria from sediments enriched with the metalloid

C. Mellado, C. Badilla, G. Escalante, V. L. Campos, M. A. Mondaca

Research output: Contribution to journalArticlepeer-review


The bacteria in environments contaminated with arsenic are affected, surviving those microorganisms that are capable of resisting this environmental pressure and to adapt by means of arsenic-resistance mechanisms: the oxidation and reduction of the metalloid. The aim of the work was to investigate the properties redox in arsenic-tolerant bacteria isolated from natural sediments. The sediments were obtained from Camarones river (I region, Chile). The samples were incubated in mineral media for 7 days, to environment temperature, with agitation. Appropriate dilutions of the samples were sowed in agar R2A and incubated to 25°C, up to 7 days. The tolerance levels for As(III) and As (V) were determined by dilution plate. The property of As- oxidizing or As-reducing of the selected bacteria was investigated using nitrate of silver. The results show the presence of As- resistant bacteria with tolerance levels to >8mM. We found that 36,84% of the bacteria isolated from arsenic-rich sediments presented arsenate reductase activity bigger than 50%. On the other hand, in bacteria isolated from sediments with low concentrations of the metalloid, arseniate reductase activity change among 10% and 25%. This indicated the arsenic selects bacteria witch tolerated high concentrations of arsenic across the transformation of As(V) en As(III).

Translated title of the contributionArsenic transformation by isolated bacteria from sediments enriched with the metalloid
Original languageSpanish
Pages (from-to)115-119
Number of pages5
Issue number534
StatePublished - 2008
Externally publishedYes


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