Isolation and phylogenetic identification of bdellovibrio and like organisms with biotechnological potential from water and soil samples

BALOs (Bdellovibrio and like organisms) are obligate predators that are usually able to survive by preying on gram-negative and in some cases gram-positive bacteria. Because these predator microorganisms can't successfully hunt every host bacteria, all population members cannot be identified in isolation from samples taken from their habitats. However, it is known that they exhibit predation against many pathogenic bacteria in different environments. This study include the isolation and identification of BALOs from water and soil samples. At certain time intervals samples from soil and wastewater of different parts of Manisa Saruhanlı Wastewater Treatment Plant (pre-sedimentation effluent, wastewater treatment plant influent, retun pump water), BALOs isolations from these samples were performed by applying differential centrifugation and filtration processes with double layer agar plate method. The presence of predatory bacteria could not be detected in all isolations from soil samples. The eight different host bacteria used for isolations were; E.coli ML35, E.coli S17, E.coli ATCC 29998, E.coli DH5a, E.coli Stbl3, Pseudomonas aureginosa, Pseudomonas syringae pv. morsprunorum and Erwinia amylovora, and the most efficient lytic plaque formation observed against E. coli ML35 (except Pseudomonas aureginosa). As a result of counting the lytic plaques seasonally by dilution plate method, it was determined that they most occurred in summer (4.5x103pfu/mL) and at least in winter (1.4x102pfu/mL). Furthermore, the interactions of predator bacteria formed lytic plaque against E. coli Ml35 have been determined against other host bacteria. In agar and broth experiments, from predator bacteria members (Bdellovibrio sp., Bacteriovorax sp. and Peredibacter sp.) only Bdellovibrio sp and Bdellovibrio bacteriovorus were able to form lytic plaque against some host bacteria. At the same time, the predator bacteria-host relationship has been confirmed by imaging them with scanning electron microscopy (SEM). DNA isolation of predator bacteria was performed from samples taken from different lytic plaques and 16S rRNA products were obtained by PCR using 4 different primer sets (BbsF216, BbsR707, Bac676F, Bac1442R, Per676F, Per1443R, Mic431F, Mic996R). After sequence analysis of the PCR products and editing of the obtained data that compared with the data in the gene bank was performed. Comparing sequence data of a total of 25 predator bacteria were identified as Peredibacter sp. (56%), Bdellovibrio bacterivorus (28%), Bdellovibrio sp. (8%) and Bacteriovorax sp. (8%) and constructed the theirs phylogenetic dendograms. As a result of the study, by isolation and identification of BALOs contributed to the predator bacterial diversity of our country. It is assumed that these predator bacteria may be used for future different biotechnological research and in particular biocontrol of pathogenic bacteria.