*2.3. Diversity of Bacteriocins Genes among Wild Marine Animals-Associated Enterococci*

A total of 30 unique bacteriocin species were identified, including 8 belonging to class I, 19 to class II, and 3 to class III (Figure 1). Although class II bacteriocins showed the greatest diversity, class III bacteriocins were most common and widely distributed. Interestingly, eight new putative bacteriocins with no significant identity to known peptides were found amongst marine enterococci genomes, including two new putative lanthipeptides (I and II) identified as class I, five unknown bacteriocins (I, II, III, IV, and V) identified as class II, and one unknown class III bacteriocin (VI) (Figure 1; Supplementary Table S4).

The most frequent class I bacteriocins were putative sactipeptides (*n* = 9), followed by unknown lanthipeptide 1 (*n* = 5), lasso peptides (*n* = 4), and thiopeptides (*n* = 4). Enterocin SE-K4 (*n* = 5) and enterocin P (*n* = 3) were the most frequent class II bacteriocins. In turn, the class III bacteriocin enterolysin A (*n* = 17) was the most frequent bacteriocin found in the 22 sequenced genomes (Figure 1).

Eight enterococcal genomes belonging to *E. hirae* (C7, DMW1-1, MP1-5), *E. avium* (L8), and *E. faecalis* (GT3-2, GT6-1, MP8-1, and ST1-20) species showed four or more bacteriocin biosynthetic genes (Figure 1). Four of these genomes (C7, DMW1-1, MP1-5, and MP8-1) encode bacteriocins belonging to three different classes (I, II, and III). Moreover, four enterococci genomes (C7, L8, ST1-20, and MP1-2) exhibited evidence of bacteriocin gene duplication (Figure 1; Supplementary Table S3). Because of their potentially new bacteriocins and/or amenability large-scale synthesis, putative class II and III bacteriocins were of special interest for further analysis.
