Arsenic contaminated environments: bioremediation perspective from molecular analysis on the bacterial arsenical metabolism

The metalloid arsenic (As) can be released from geological formations and it is widely used in anthropogenic activities (industry, agriculture, etc.) contaminating several aquatic and soil environments. The arsenate As(V) and arsenite As(III) can be subject to microbiologically oxidation, reduction and methylation reactions. Indeed, bacterial metabolisim of arsenical species in the environment is critical in the As cycle. In the present study, novel aerobic bacterial strains responsible for the oxidation and reduction of As were isolated in water samples supplemented with arsenite or arsenate.

We collected surface water from Lake Albano, a crater lake in the volcanic district of Alban Hills, southeast of Rome (Italy), and from Tiber River, Rome. All the culturable bacteria were identified on the 16S rDNA gene sequences and RpoD e Rho gene sequences. Aeromonas, Brevundimonas, Pseudomonas and Chryseobacterium (Bacteroidetes) were the genera of bacteria arsenate-resistent or able to reduce As(V) under aerobic conditions. Among the As(III) oxidizers or arsenite-resistent bacteria: Comamonas, Klebsiella and Enterobacter, Shinella, Rheinheimera and Bacillus (Firmicutes). Moreover, molecular and phylogenetic analysis were conducted on the genes codifying the As(V)-rductases and the As(III)-oxidases. However, the pathway of arsenate reduction/arsenite oxidation for some isolates was via hitherto unknown mechanisms.



Copyright: © Aristotle University of Thessaloniki
Source: 2nd International Conference 2009 (Juni 2009)
Pages: 7
Price: € 5,00
Autor: Domenico Davolos
Bianca Maria Pietrangeli

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