Isolation and Identification of Halophilic and Halotolerant Bacteria From Badab-e Surt Travertine Spring, Kiasar, Iran, and Investigation of Calcite Biomineralization Induction

Badab-e Surt spring is a travertine spring that has low to moderate levels of salt, so it is a good model for isolating moderately halophilic bacteria and investigating the relationship between microbe and environment. For isolating bacterial strains, water and sediment samples were collected from different springheads of the Badab-e Surt spring. Among the 171 bacterial isolates, 110 strains were halophiles. According to comparative partial 16S rRNA sequence analysis, the selected halophilic gram-positive and gram-negative strains were identified as members of the genera: Roseovarius, Labrenzia, Erythrobacter, Erythromicrobium, Massilia, Marinobacter, Halomonas, Shewanella, Pseudomonas, Flavobacterium, Bacillus, Brevibacterium, Staphylococcus, Microbacterium, Kocuria, and Streptomyces. To investigate mineralization, potential strains were screened by the culturing method, and then analyzed with a polarizing and scanning microscope. Five strains, Bss-11a, Bss-3, Bsw-1c1, Bsw-28d, and Bsw-39b, had potential for the mineralization of calcite that very closely resembled species Bacillus cohenii DSM 6307(T), Labrenzia aggregate IAM 12614(T), Bacillus safensis FO-036b(T), Marinobacter flavimaris SW-145(T), and Marinobater adhaerens HP15(T), respectively.