Anti-listerial peptides from a marine FTL7: production optimization, characterizations and molecular docking studies.

Unlabelled: Antimicrobial peptides (AMPs) with potent anti-listerial activity were characterized from a novel marine FTL7. A Box-Behnken statistical experimental design was used to study the combined impact of culture conditions on the production of AMPs by FTL7. The conditions optimized by statistical experimental design were 34.5 °C incubation temperature, 23 h incubation time, and 7.6 initial pH of the medium. AMP purification was performed by ammonium sulphate fractionation and butanol extraction followed by reversed-phase C solid-phase extraction. Tricine-SDS-PAGE analysis revealed a peptide with a molecular mass of ~ 6.5 kDa in an active AMPs fraction, whereas the mass spectrometry (MS) analysis showed the presence of AMPs in the mass range of 1-1.6 kDa, along with a 6.5 kDa peptide. Both MS and MS/MS analysis confirmed the AMPs as lipopeptides including surfactin, fengycins and iturin A and a circular bacteriocin amylocyclicin. The minimum inhibitory concentration of these AMPs against Scott A was 2.5 µg/mL. Further, the in-silico docking studies showed that the AMPs from FTL7 have high binding energy and stable binding patterns towards target proteins. Thus, this new combination of AMPs can serve as an effective food bio-preservative.

Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-024-03944-5.