Extended-Spectrum Antimicrobial Activity of the Low Cost Produced Tilapia Piscidin 4 (TP4) Marine Antimicrobial Peptide

Regarding the spread of antibiotic-resistant infections in recent years, many studies have been conducted on antimicrobial peptides as an alternative drug. Unfortunately, there are fewer studies on marine antimicrobial peptides than other living organisms. In this study, Tilapia Piscidin 4 (TP4), one of the most efficient marine antimicrobial peptides that have been introduced so far, produced using the Pichia pastoris GS115 expression system. The TP4 sequence was first cloned to the pPIC9 vector and then transformed to the Pichia pastoris to integrate into the genome. The best expression conditions were obtained in a minimal protein-lacking medium of BMM, 1.5% methanol, pH of 6, and the time of 48 hours. Subsequently, the antimicrobial activity of the recombinant TP4 was evaluated on 12 gram-negative and 5 gram-positive common bacterial pathogens including sensitive and antibiotic-resistant strains and showed the widespectrum activity. The TP4 antimicrobial peptide can be used as a competitive candidate for antibiotics in the post-antibiotic era due to the broad-spectrum antibacterial effects. The production of TP4 by the explained method in this study was a low-cost process and could pave the way for future studies and therapeutic applications.