Arsenic-hypertolerant and arsenic-reducing bacteria isolated from wells in Tucumán, Argentina

MAIZEL, DANIELA; BALVERDI, PILAR; ROSEN, BARRY; SALES, ADRIANA M.; FERRERO, MARCELA A.

CANADIAN JOURNAL OF MICROBIOLOGY

NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS

Año: 2018 vol. 64 p. 876 - 886

0008-4166

Arsenic hyper-tolerant bacteria were isolated from arsenic-contaminated well water from the village of Los Pereyra in Tucum¨¢n province, Argentina. Microorganisms that biotransform arsenic are a major factor in arsenic mobilization in contaminated aquifers. Groundwater analyses showed a level of arsenic contamination (average concentration of 978 ¦Ìg.L-1) that exceeds the safe drinking water limit of 10 ¦Ìg.L-1 recommended by the World Health Organization (WHO) and the Argentine Food Code (AFC). There was considerable spatial variability in the concentration of arsenic in each of the wells analyzed, as well as in the distribution of the major anions HCO3 , SO4 2- and Cl-. Eighteen bacterial strains were characterized. Six strains belonging to the Actinobacteria phylum, were able to grow in media with 20 mM As(III) or 200 mM As(V) and were also highly resistant to Cr, Cd and Cu. Their ability to biotransform arsenic was examined by speciation of the products using high performance liquid chromatography (HPLC) inductively coupled plasma mass spectrometry (ICP-MS). In addition, two strains, Brevibacterium sp. AE038-4 and Microbacterium sp. AE038-20, were capable of aerobic arsenate reduction, which suggests that these strains could increase the mobility of arsenic by formation of more mobile As(III).