Lactococcus garvieae FR6: A multi-bacteriocin producer from lantana flowers origin

This study reports the first known simultaneous production of garviecin Q and garvicin ML and a new bacteriocin (garvieacin FR6) by Lactococcus garvieae FR6. These bacteriocins were isolated from the culture supernatant of the FR6 strain using hydrophobic interaction, cation-exchange, and reverse-phase chromatography. ESI-TOF MS confirmed its predicted molecular masses of 5321.68 Da (garvieacin FR6), 5346.64 Da (garvieacin Q), and 6010.64 Da (garvicin ML), and genome sequencing identified three distinct bacteriocin gene clusters. The genome analysis revealed that garvieacin FR6 belongs to the linear class IId bacteriocin, similar to garvieacin Q, and is characterized by gene clusters that encode essential components for producing these bacteriocins, including immunity proteins and an ATP-binding cassette (ABC) transporter. In addition, garvieacin FR6 has a narrower antimicrobial spectrum compared to garvieacin Q and garvicin ML, particularly with low minimum inhibitory concentrations against Latilactobacillus sakei (0.54 μM) and Lactococcus garvieae strains (0.13 μM). Therefore, the FR6 strain produces three bacteriocins from different subclasses, each with a distinct antimicrobial spectrum. The co-expression of garvieacin Q, garvicin ML, and the novel bacteriocin garvieacin FR6 provides a practical source of bacteriocins for food biopreservation and a platform for the development of targeted antimicrobials. Especially where combined peptides may enhance effectiveness and help prevent resistance by offering complementary inhibition pressure. Future work should focus on performance and synergy in real food matrices, defining the mechanism of action and immunity/resistance determinants, and establishing scalable production, formulation, and safety data to support translational use.