Aspergillus flavus is a toxigenic fungus well known for the synthesis of aflatoxins that contaminate crops and food products. Antifungal peptides generated by lactic acid bacteria have a high potential for applications as biocontrol agent to prolong the shelf life of crops. In this study, antifungal activity of peptides generated by Lactobacilli's plantarum TE10 was tested against the spoilage fungi Aspergillus flavus MD3. L. plantarum TE10 was inoculated in MRS broth and incubated at 37 degrees C for 48 h and the antifungal activity was determined using dual agar overlay method. The cell free supernatant was fractionated using size exclusion chromatography, and the peptides were identified using LC-MS/MS. Scanning electron microscope was performed to determine the effects of the active fraction on the morphology of target fungi. The antifungal activity of the active fraction was further confirmed against selected fungi in fresh maize seeds. A total of 37 peptides were identified in fraction 7 that showed the highest antifungal activity. The peptides mixture in fraction 7 caused damage at the tip of the mycelia as observed by scanning electron microscope. Growth of A. flavus was observed after 7 days on the samples treated with distilled water and MRS broth, while slight growth was observed on the sample treated with fraction 7. Fraction 7 reduced the spore formation of A. flavus by 4 folds compared to the control. The results demonstrated promising application of the peptides mixture as bio-control agent to prevent the growth of A. flavus in maize.

Aspergillus flavus is a toxigenic fungus well known for the synthesis of aflatoxins that contaminate crops and food products. Antifungal peptides generated by lactic acid bacteria have a high potential for applications as biocontrol agent to prolong the shelf life of crops. In this study, antifungal activity of peptides generated by Lactobacilli's plantarum TE10 was tested against the spoilage fungi Aspergillus flavus MD3. L. plantarum TE10 was inoculated in MRS broth and incubated at 37 degrees C for 48 h and the antifungal activity was determined using dual agar overlay method. The cell free supernatant was fractionated using size exclusion chromatography, and the peptides were identified using LC-MS/MS. Scanning electron microscope was performed to determine the effects of the active fraction on the morphology of target fungi. The antifungal activity of the active fraction was further confirmed against selected fungi in fresh maize seeds. A total of 37 peptides were identified in fraction 7 that showed the highest antifungal activity. The peptides mixture in fraction 7 caused damage at the tip of the mycelia as observed by scanning electron microscope. Growth of A. flavus was observed after 7 days on the samples treated with distilled water and MRS broth, while slight growth was observed on the sample treated with fraction 7. Fraction 7 reduced the spore formation of A. flavus by 4 folds compared to the control. The results demonstrated promising application of the peptides mixture as bio-control agent to prevent the growth of A. flavus in maize.

The ability of Leuconostoc mesenteroides DU15 to produce antifungal peptides that inhibit growth of Aspergillus niger was evaluated under optimum growth conditions of 30 degrees C for 48 h. The cell-free supernatant showed inhibitory activity against A. niger. Five novel peptides were isolated with the sequences GPFPL, YVPLF, LLHGVPLP, GPFPLEMTLGPT, and TVYPFPGPL as identified by de novo sequencing using PEAKS 6 software. Peptide LLHGVPLP was the only positively charged (cationic peptides) and peptide GPFPLEMTLGPT negatively charged (anionic), whereas the rest are neutral. The identified peptides had high hydrophobicity ratio and low molecular weights with amino acids sequences ranging from 5 to 12 residues. The mode of action of these peptides is observed under the scanning electron microscope and is due to cell lysis of fungi. This work reveals the potential of peptides from L. mesenteroides DU15 as natural antifungal preservatives in inhibiting the growth of A. niger that is implicated to the spoilage during storage.