Detection of Iturin A from Bacillus atrophaeus by HPLC and Mass Spectrometry Analysis and Evaluation of its Antifungal Activity

Abstract

Background: Bacillus species create several kinds of metabolites, which contain cyclic lipopeptide-type antibiotics, consisting of three major families: fengycin, surfactin, and iturin. Iturin demonstrates powerful biocontrol characteristics and can restrain the growth of a diversity of plant fungal pathogens. Objective: The current study investigates the identification of iturin A from Bacillus atrophaeus using HPLC and Mass spectrometry analysis and evaluate its antifungal effects. Materials and Methods: In this study, the lipopeptide antibiotics were isolated by HPLC and characterized by MS. Then, the lipopeptides were examined for their ability to antagonize the growth of different pathogenic fungi. Antifungal performance of the lipopeptides was determined against Fusarium oxysporum, Aspergillus niger, Penicillium chrysogenum, and Mucor hiemalis according to well diffusion and percentage of growth inhibition. Results: Bacillus atrophaeus HNSQJYH170, isolated from Isfahan soil, offered strong fungicidal activity by producing cyclic lipopeptide-type antibiotics. Inhibition zones were 17.55, 17, 18.50, and 20.99 mm, and the percentages of growth inhibition were 78.54, 62.55, 83.11, and 84/95 for Fusarium oxysporum, Penicillium chrysogenum, Mucor hiemalis and Aspergillus niger, respectively. The spectrum represented the iturins family in retention times of 32.423–33.893 min. MS demonstrated molecular ion peaks (M+H) + for iturin at m/z 1029.55, 1043.60, 1051.55, 1065.60, 1079.60 and 1093.65. The inhibition rate against all fungi on the seventh day of incubation was higher than 80%. Among them, Aspergillus niger was the most sensitive fungal species with an average of 84.95% inhibition. Conclusion: According to the results, Bacillus atrophaeus HNSQJYH170 could operate as a biocontrol agent against a wide spectrum of pathogenic fungi.