DNA Metabarcoding from Microbial Communities Recovered from Stream and Its Potential for Bioremediation Processes.

Urban waste (UW) has caused a series of problems regarding its management. UW comprises domestic, hospital and industrial residues, which makes the destination of this waste a matter of concern, as it may contain a variety of highly toxic environmental polluters. Deactivated dumps can represent sources of contamination of the environment that surround these deposits, harming rivers and inhabiting organisms. Knowledge of the microbial profile of water bodies that can be affected by these toxic residues is essential for the development of alternatives and improvements in treatments applied in rivers and streams. In this sense, this work aimed to analyze the microbial community present in sediments of the Arroio Dourado stream in the municipality of Foz do Iguaçu, a stream located near a deactivated open-air dump. 16S rDNA metabarcoding suggested the dominance of acidogenic bacteria belonging to Acidobacteriota phylum, followed by less abundant phyla Actinobacteriota, Myxococcota, Chloroflexi and a small community of sulfate reducers (Desulfobacteriota). However, more than 50% of amplicon sequence variants (ASVs) were not taxonomically classified. In addition, an expressive abundance was attributed to the genus Anaeromyxobacter, a metabolically versatile group, which can thrive in the presence of polluting compounds present in the deactivated landfill. Thus, a possible stream treatment process can be developed. In addition, culture media can be developed for the recovery of taxonomic groups identified involved in the biodegradation of organic compounds. The results presented expand the knowledge of bacterial diversity in sediment samples recovered from the Arroio Dourado stream.

Yeasts isolated from a lotic continental environment in Brazil show potential to produce amylase, cellulase and protease.

Yeasts have wide applicability in the industrial field, as in the production of enzymes used in biocatalysts. Biocatalysts are more efficient when compared to chemical catalysts, with emphasis on hydrolytic enzymes, such as amylase, cellulase and protease. Here we focused on prospecting yeasts, with a high capacity to synthesize hydrolytic enzymes, from a continental lotic ecosystem environment in Brazil. 75 yeasts were grown in Yeast Extract-Peptone-Dextrose (YPD) medium supplemented with antibacterial and their capacity for enzymatic production was tested in specific media. Accordingly, 64 yeasts showed enzyme production capacity. From those, six showed good enzyme indexes, 3 for amylase, 2 for cellulase and 1 for protease. All showed at least one hydrolytic enzyme activity for the tested enzymes (amylase, cellulase and protease), which suggested that the yeasts are metabolically active. By sequencing the 26S gene, we identified Naganishia diffluens and Apiotrichum mycotoxinivorans as the species with highest enzyme production activities. Those species showed potential for application as biological catalysts in the biotechnological scope, collaborating in a sustainable way for the development of industrial products.