Extraction and Characterization of Iturin A as a Key Factor in the Antagonism of Bacillus amyloliquefaciens M13RW01 toward Pathogenic Fungi.

Background: Bacillus amyloliquefaciens contains several fungal inhibitory compounds, such as peptides and lipopeptides, representing the remarkable potential for biotechnological, agricultural, and biopharmaceutical applications.

Objectives: This research aimed to extract and characterize iturin A as the key antagonism factor of Bacillus amyloliquefaciens M13RW01 toward pathogenic fungi, using HPLC and mass spectrometry [MS] analysis.

Methods: For this study, Bacillus amyloliquefaciens strain M13-RW01 isolated from Isfahan soil was used. The lipopeptide compounds of B.amyloliquefaciens were examined for antagonistic performance against Aspergillus niger PTCC 5010, Mucor hiemalis PTCC 5292, Fusarium oxysporum CBS 62087, and Penicillium chrysogenum PTCC 5037 by well diffusion and percentage of growth inhibition. The crude extract was run on Waters μBondpak C18 column in the HPLC system to separate the antibiotics. Major antibiotics were analyzed based on MS.

Results: HPLC analysis demonstrated that the lipopeptide compound is similar to iturin A. Moreover, MS analysis of these compounds and purified iturin A revealed a high similarity between them, with the same molecular ion peaks identified. Results showed that the produced lipopeptides by Bacillus amyloliquefaciens were of iturin A genum. The molecular ion peaks of the B.amyloliquefaciens M13RW01 methanolic fraction were at 1027.10, 1043.05, 1058, 1066, 1072, 1088.95. These compounds restrained fungal germination and growth. Inhibition growth percentages were 79.28, 76.13, 84.47and 59.15% for Aspergillus niger, Mucor hiemalis, Fusarium oxysporum, and Penicillium chrysogenum, respectively.

Conclusion: According to the present study, B.amyloliquefaciens M13RW01 lipopeptides are able to inhibit the growth of some fungi. B.amyloliquefaciens M13-RW01 isolated from Isfahan soil plays an essential part in antagonizing pathogenic fungi. Thus, this antifungal lipopeptide is supposed to be a biological protection agent for farm crops.