RESUMO
The phylum Firmicutes comprises seven classes where most species are either aerobic or anaerobic endospore former. Inside Firmicutes, species allocated in the genus Bacillus and related genera are collectively named aerobic endospore-forming bacteria (AEFB), and the soil is their major reservoir. AEFB have great importance in health, agriculture, and biotechnology although the more studied species are Bacillus subtilis and the human pathogens Bacillus cereus and Bacillus anthracis. AEFB have great importance in health, agriculture, and biotechnology; although the knowledge about these organisms is based on few species, notably, Bacillus subtilis, Bacillus cereus, and Bacillus anthracis. In this work, we generated partial 16S rRNA gene sequences of both strands of 192 AEFB strains isolated from soils of Distrito Federal, Brazil (SDF strains). The resulting consensus sequences were used to obtain taxonomic assignment and establish the phylogenetic relationships among these strains. Through this approach, we could observe that classified SDF strains were distributed among genera Bacillus (169 strains; 88.02%), Paenibacillus (11; 5.73%), Lysinibacillus (6; 3.13%), Brevibacillus (4; 2.08%), Terribacillus (1; 0.52%), and Rummeliibacillus (1; 0.52%). Phylogenetic trees revealed these 192 SDF strains can be segregated into eight groups spanning families Bacillaceae and Paenibacillaceae belonging to the order Bacillales. To expand the knowledge about the diversity of these SDF strains, further studies regarding characterization with different methodologies are underway
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Assuntos
Poluentes do Solo/análise , Análise do Solo , Esporos Bacterianos/isolamento & purificação , Contagem de Colônia Microbiana , RNA Ribossômico 16S/genética , Bactérias Anaeróbias/isolamento & purificação , Bacillales/isolamento & purificação , Esporos Fúngicos/genética , Brasil , Bacillales/genética , Perfilação da Expressão Gênica/métodosRESUMO
Microalgal-bacterial co-cultures were employed for the treatment of artificially prepared metal-rich wastewaters in this study. For the purpose, highly metal-resistant microalgal and bacterial species were isolated from a leading wastewater channel flowing through Lahore, Pakistan, and characterized at the molecular level. The microbial identities were proved after BLAST analysis. The microalgal (Chlorella vulgaris-BH1) and bacterial (Exiguobacterium profundum-BH2) species were then co-cultured in five different proportions. Five different proportions of potentially mutualistic microbial co-cultures (comprising of microalgal to bacterial cells in ratios of 1:3, 2:3, 3:3, 3:1, and 3:2) prepared thus were employed to remediate artificially prepared metal-loaded wastewaters. Three randomly selected toxic metals (Cu, Cr, and Ni) were used in this study to prepare metal-rich wastewaters. The microalgal-bacterial co-cultures were then exposed independently to the wastewaters containing 100 ppm of each of the above mentioned metals. The inoculated wastewaters were incubated maximally for a period of 15 days. The metal uptake was noted periodically after every 5 days. The results of the present study depicted that maximally about 78.7, 56.4, and 80% of Cu, Cr, and Ni were removed, respectively after an incubation period of 15 days. The microbial co-culture consisting of microalgal to bacterial cells in a ratio of 3:1 showed the highest remedial potential. The findings of the present study will be helpful in developing effective microalgal-bacterial consortia for economical, efficient, and environment-friendly rehabilitation of the polluted sites
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