Study of bacterial community structure and diversity during the maturation process of a therapeutic peloid

The presence of bacteria in peloids is essential for the development of their therapeutic properties. Therefore, the study of bacterial community composition in peloids and its changes along the maturation process is of paramount importance. For this purpose, samples of thermal waters and peloids at different stages of maturation were collected and the MiSeq Illumina sequencing platform was employed to obtain information on bacterial diversity and community structure. Richness and diversity indices showed that a clear change during the first period of maturation occurred, while, after two months, the community seemed to stabilize. The same results were obtained based on the different OTU present. A phylogenetic analysis was performed and taxonomic affiliations for sequences with abundance higher than 1% and important to determine differences among samples were obtained. Relative abundance of bacterial community composition was also investigated. Analysis indicated a dominance of α- and β-Proteobacteria in water samples, while γ-Proteobacteria prevailed in peloids. Again, biodiversity profiles showed a low level of similarity between water and peloids, while in all peloid samples the populations were almost the same. Results demonstrate that the bacterial community in peloids changed mostly on the early stages of maturation and it reached stability after two months.