Distribution of Bacillota in Water and Sediments from Aquatic Environments.

The phylum Bacillota comprises metabolically diverse bacteria with potential relevance in several fields. Although some genera, such as Bacillus and others, have been extensively studied, the distribution of Bacillota in the environment is still poorly understood. This study aimed to analyze the distribution of Bacillota present in water and sediment samples from different environments. For this purpose, water (W) and sediment (S) samples were collected from different marine environments (Dois Rios Beach - DR, Abraão Beach - AB, Massambaba Beach - MB, and Guanabara Bay - GB), freshwater lagoons (Jacarepiá Lagoon- JL) and hypersaline lagoons (Vermelha Lagoon - VL), all of which are located in Rio de Janeiro, Brazil. The microbial communities present in each sample were determined by sequencing 16S rRNA-encoding genes. The distribution and diversity of Bacillota were analyzed via QIIME2. The results revealed that Bacillota represented an average of 1% of the microbial community of aquatic microbiomes and were unevenly distributed in aquatic water and sediment. The highest abundances of Bacillota were detected in JL_S and VL_S, and the lowest abundances were observed in MB_W and AB_W. Only sequences related to the Bacilli and Clostridia classes were identified. The main Bacillota genera identified were Bacillus and an unidentified Clostridiales order genus. The VL_S and JL_S samples had the highest numbers of exclusive Bacillota genera. On the other hand, 15 Bacillota genera, which are generally observed in the human and animal guts, were found only in anthropogenically impacted GB_W and AB_W. The obtained results revealed how Bacillota are distributed in different aquatic environments.