Study of antimicrobial Effect agent of Bacillus amyloliquefacienson on human and plant Pathogens

Abstract

The new problem for medical science is antimicrobial resistance and finding new antimicrobial agents. Some types of antibiotic which produced by several several species of microorganisms have ability to lysis cell wall of bacteria. These types of antibiotic own large portion in markets. One of microorganisms producing antibiotic is Bacillus sp. Bacillus amyloliquefaciens is gram positive, aerobic, and spore forming bacteria. The bacterium can produce some antimicrobial materials such as lipopeptides، surfactin، fengycin، bacillomycin D، polyketide (difcidin) and dipeptide bacilysin. Objective: The present study aimed to screen production of antimicrobial agent from Bacillus amyloliquefacien on human and plant patogens, which isolated from honey from south of Iran.

Materials and methods:

First of all, Bacillus amyloliquefacien was cultured in nutriant broth medium after that it was incubated at 37 ̊C for 72 h. Then in order to isolate the antimicrobial material, the broth medum was centrifuged and the supernatant was isoleted. The antimicrobial effect was tested by well diffusion agar aginst E.coli, klebsiella pneumoniae, Xanthomonas campestris, Pseudomonas syringae, Erwinia amylovora, Rhizobium radiobacter, Aspergillus flavus, Fusarium oxysporum, Streptococcus mutans, Shigella flexneri, Neurospora crassa, Botrytis cinerea and Candida albicans . After that, MIC and MBC were utilized for understanding the mimum inhibition cosentration.

Results: The antimicrobial studies showed that B. amyloliquefacien has ability to produce antimicrobial against plants pathogenic microorganisms. In the study, the isolated agent had antimicrobial effects on F. oxysporum and N. crassa. The antimicrobial agent has antimicrobial effect on F. oxysporum until 12.5 mg/ml and N. crassa until 25 mg/ml . But the antimicrobial agent had not any effect on pathogenic bacteria. Conclusion: The isolated Bacillus amyloliquefacien has ability to produce antifungal agents and the beacteria can not produce antibacterial agents.