Microbial diversity and contamination in Reconquista River sediments: detection of bacteria with potential biotechnological applications

N. PORZIONATO; ZILIANI A.; GRIMOLIZZI, C.; VAZQUEZ, S.; TUFO, ANA; CURUTCHET, G.

Simposio; 6 ISEBE. The Sixth International Symposium of Environmental Biotechnology and Engineering; 2018

Sediments from contaminated water courses accumulate large amounts of organicmatter and toxic persistent pollutants like heavy metals and pesticides. The stresscaused by severe contamination leads to the selection of microorganisms which, inaddition to being involved in in situ self-purification processes, have a clearbiotechnological potential. In this work, we studied the microbial communities fromfluvial sediments in areas with different degree and type of contamination at theReconquista River basin, one of the most polluted watercourses in the metropolitanarea of Buenos Aires, Argentina. Our aim was not only to get insight on thecomposition of bacterial communities in these habitats but also to recover in culturebacteria capable of growing at the expense of the pollutants. The sedimentsamples were analyzed to determine their physicochemical parameters andrespirometry experiments were performed. Bacterial community structure insediment samples was analyzed through 16S rRNA gene amplicon sequencing(V4 variable region, Illumina MiSeq platform, and data were processed usingMothur and R packages). Cultures were performed to enrich in sulphate and ironreducers and sulfur and iron oxidizers using selective media, and isolates wereobtained in solid media. Taxonomic identification of isolates was achieved bypartial sequencing of the 16S rRNA gene after DNA extraction using theWizard® Genomic DNA Purification Kit (Promega) and PCR amplification using theuniversal primers 27F/1492R for bacteria and ITS5/ITS4 for yeasts. Growthkinetics and metabolites production were studied for the enrichment cultures andisolates obtained. Bacterial communities from areas with different contaminationstatus differ in their structure (and therefore, in their functional potential andperformance). Aerobic and anaerobic isolates, affiliated to Acidithiobaclllus,Clostridium, Desulfovibrio, and Shewanella among others, were obtained. Thesemicroorganisms possess a great potential for applications in environmentalbiotechnological processes.