PROKARYOTIC ASSESSMENT IN GEOTHERMAL AND VOLCANIC ZONES IN ARGENTINA: METAL AND METALLOID RESISTANCES AND BIOTECHNOLOGICAL APPLICATIONS

MARIA ALEJANDRA LIMA; GRACIANA WILLIS PORATTI; EDGARDO DONATI; ANA BELEN SEGRETIN; MARCELA HIPPERDINGER; FRANCISCO MASSELLO; CAMILA CASTRO; MARIA SOFIA URBIETA

Valencia

Congreso; FEMS Microbiology Congress 2017; 2017

Federation of European Microbiological Societies

Assessing microbial communities in extreme environments such as volcanic/geothermal zones, allows for the search of novel extremophilic microorganisms that can be of use in the development or improvement of biotechnological processes. Most microbial communities developed in such harsh environments have different heavy metal resistance strategies of importance in some technological applications as biomining but also in the bioremediation of metal(loid) polluted environments. Our aim was to investigate the microbial diversity of Copahue geothermal system with temperatures up to 90°C and pH values from 2 to 7 under aerobic and anaerobic conditions. Three different approaches were used, enrichment to isolate autochthonous microorganisms able to grow in the presence of high metal(loid) concentrations, and two culture independent alternatives (amplification and sequencing of the complete 16S rRNA gene of the entire community and fluorescent in situ hybridization). In addition, such communities were used in biotechnological applications related to heavy metal bioremediation . Bacteria (acidophilic species related to AMD) dominated the acidic areas of moderate temperature, while archaea prevail in high temperature ponds. In the water samples, the dominant prokaryotes were chemolithoautotrophic or mixotrophic, mainly sulfur oxidizers while in microbial biofilms photosynthetic species were the most important primary producers. In the case of the acidic river, Rio Agrio, also mainly sulfur oxidizing bacteria and archaea were found although some iron oxidizing microorganisms were also detected. Some microbial communities isolated showed the ability to precipitate metals even at very low pH values and to reduce hexavalent chromium to the less toxic trivalent chromium.