In vitro antifungal activity of bioactive peptides produced by Lactobacillus plantarum against Aspergillus parasiticus and Penicillium expansum

- Antifungal activity of peptides against A. parasiticus and P. expansum in liquid medium.
- Purification of the bioactive peptides through chromatographic techniques.
- Identification of the bioactive peptides structure through MALDI-TOF mass spectrometry.

Food spoilage caused by mycotoxigenic moulds represents an important problem in food security. The antimicrobial peptides are compounds of natural origin constituted by a variable number (5-100) of amino acids held together through peptide bonds. In this work, the cell free supernatants (CFSs) containing peptides obtained from four strains of LAB were lyophilized, filtered and tested to determine the antifungal activity against Aspergillus Parasiticus and Penicillium expansum. CFS obtained by Lactobacillus plantarum showed the highest inhibition activity. CFS was fractionated by size exclusion chromatography and injected into the liquid chromatography coupled to diode array detector. One of the recollected fractions resulted interesting for the presence of three peaks that were purified by the technique of the LC-DAD using a semi preparative C18 column. Finally, the antifungal activity of the purified peptides was studied against A. Parasiticus and P. expansum in liquid medium. The MALDI-TOF/TOF mass spectrometry was used for the peptides identification. The three purified peptides presented an amino acidic sequence identified by a bioinformatics program of SGADTTFLTK, LVGKKVQTF, and GTLIGQDYK. The first peptide purified reduced 58% and 73% the growth of P. expansum and A. parasiticus, respectively, in liquid medium after 48 h incubation.