## 3 Results
### Grouping and Identification of Bacterial Isolates Exerting Antibacterial Activity
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline
**Group** & **Strain** & **bp** & **\% Identity** & **Antibacterial Activity 1** & **Bacteria** & **Accession Number** & **NRPS** & **PKS** \\ \hline W & CTB93 & 1379 & 99.8 & 1,2 & _T. saccharopathies_ & MW700054 & - & - \\ \hline Y & CTB69 & 1416 & 99.6 & 2,4.5 & _Pamphilis_ sp. & MW700052 & + \({}^{*}\) & + \({}^{*}\) \\  & & & & & (_P.coplasma_/_P. polyconsachusetts_/_city_) & MW700058 & - & - \\ \hline LAB1 & CT2H & 440 & 99.8 & 1,2,3.4 & _S. epidermidis_ & MW700058 & - & - \\ \hline LAB1 & CT7C & 580 & 100 & 3,4.5 & _S. wormsari_ & MW700060 & - & - \\ \hline LAB2 & CT6C & 563 & 99.6 & 1,2,3.4.5 & _S.suffrate_ & MW700059 & + & - \\ \hline LAB3 & CT12B & 432 & 99.8 & 1,2.5 & _S.S._ & \(M\) & MW700061 & - & - \\ \hline \end{tabular}
* * Amplicons were sequenced. 1 (1) S. aureus, (2) P. aeruginosa, (3) S. Typhimurium, (4) A. hummeri, (5) C. _Pamphilis_  
\end{table} 
Table 2: _Cont._Furthermore, all 50 isolates were screened for the presence of NRPS and PKS-I biosynthetic gene clusters. In fourteen isolates, NRPS genes were detected; six isolates were tested positive for PKS gene clusters whereas in 13 isolates both NRPS and PKS gene clusters were detected. Twenty-six out of 31 (83.9%) bacterial isolates identified as _Bacillus_ spp. tested positive for NRPS or PKS or both. Specifically, 11 out of the 31 (35.5%) bacterial isolates identified as _Bacillus_ spp. tested positive only for NRPS genes (78.6% of the isolates positive for NRPS, 11/14), 5 were positive only for PKS genes (83.3% of the isolates positive for PKS, 5/6) and 10 isolates were detected positive for both NRPS/PKS gene clusters (76.9% of all isolates positive for both NRPS and PKS, 10/13). Moreover, only NRPS genes were detected in 4 out of 5 identified _B. pumilus_ strains (CTA1, CTA2, CTA15, CTB21), in 2 out of 9 _Bacillus_ sp. (CTA31, CTA14), and in 2 out of 7 _B. safensis_ strains (CTB16, CTB120). _B. licheniformis_ (CTA163), _P. megaterium_ (CTA7), and _B. paramycooides_ (CTA28) were also positive just for NRPS genes. Two _B. safensis_ (CTA146, CTB7) and 3 _Bacillus_ sp. (CTA109, CTB11, CTA125) strains were positive just for PKS gene clusters. Both NRPS and PKS genes were detected in _B. vallismortis_ (CTA16), in 4 _B. subtilis_ strains (CTA5, CTA9, CTA10, CTA20), 3 _B. safensis_ (CTA57, CTB43, CTB89), and 2 _Bacillus_ spp. (CTB31, CTA46) strains. Two out of 4 (50%) bacterial isolates identified as _Pseudomonas_ spp. tested positive for NRPS (_P. fulva_ CTA23) or both NRPS/PKS (_Pseudomonas_ sp. CTA90) gene clusters. In addition, 2 out of 7 isolates identified as _Staphylococcus_ spp. tested positive for NRPS (_S. arlettae_ CT6C) and PKS (_S. cohini_ CTB46) gene clusters. The strain _M. imperiale_ (CTA95) was positive for NRPS encoding genes, while in _P. profundus_ (CTA169) and _Paenibacillus_ sp. (CTB69) both NPRS and PKS gene clusters were detected. Twelve NRPS amplicons and 11 PKS amplicons were sequenced, in order to validate the PCR result (Tables 3 and 4). Ten out of 12 amplicons were indeed identified as NRPS gene clusters. The identification of the other two amplicons was not possible due to low quality of sequencing data. In most cases there was an agreement regarding the genus classification and sequencing results, except for amplicons A1 and A7 that were amplified from bacterial isolates belonging to _Bacillus_ spp., whereas the NPRS amplicons shared homology with NRPSs of _P. motelii_. Amplicons A10, A20, and A46 from the strains _B. safensis_ (CTA10), _B. safensis_ (CTA20), and _Bacillus_ sp. (CTA46) were identified as NRPSs that were implicated in surfactin biosynthesis, while B69 from the strain _Paenibacillus_ sp. shared homology with the subunit B of gramicidin synthase. Furthermore, the sequencing data verified the PCR results for the 11 tested PKS amplicons. Six amplicons exhibited homology with ketosyntheses, (A5, A9, A10, A20, A125, B11), 3 were identified as PKSs (A109, B31, B69), while amplicon A16 was identified as amino acid adenylation domain-containing protein.