Inhibitory activity of two synthetic Pharabitis nil (L.) antimicrobial peptides against common spoilage yeasts

Abstract

Fighting food waste caused by spoilage yeasts and developing more natural forms of preservatives are critical points for the food industry. Plant antimicrobial peptides have biological activity against a broad spectrum of microorganisms, which could represent a valid alternative to the current preservative agents. In this work, the Pharabitis nil antimicrobial peptides Pn-AMP1 and Pn-AMP2 were chemically synthesised, and the potency of their antiyeast activity against common spoilage yeasts was measured. Pn-AMP1 showed a better inhibitory effect than Pn-AMP2, therefore it was further characterised. Pn-AMP1 displayed fast inhibitory activity against yeast strains Kluyveromyces lactis and Zygosaccharomyces bailii, and the antiyeast mechanism of membrane permeabilisation was detected. Its safety in terms of human consumption was studied and no adverse effects were found. Lastly, the stability of the peptide in different environments and conditions, such as heat, high salt, and a range of pH were studied, in addition to their antiyeast activity in different food matrices such as a soft drink and dairy product, further supporting Pn-AMP1’s potential for use in food preservation.