Characterization of antimicrobial compounds produced by Pseudomonas aurantiaca S-1.

Pseudomonas aurantiaca S-1 can serve as a natural source of pesticides towards phytopathogens like Fusarium oxysporum P1 and Pseudomonas syringae pv. glycinea BIM B-280. The largest pool of produced antimicrobial compounds was found in four days-old spent culture supernatant. At least two groups of bioactive substances were identified, one responsible for the antibacterial activity and the other for the antifungal activity. The fraction with strong antibacterial activity had the molecular mass 282.8 and formula C18H36NO, and the fraction with strong antifungal activity had molecular mass 319.3 and molecular formula C20H31O3 which could be a new fungicide. Additionally, P. aurantiaca S-1 was able to produce indoleacetic acid and siderophores.