ANTIFUNGAL ACTIVITY OF PSEUDOMONAS-FLUORESCENS STRAIN FSJ-3 ISOLATED IN MOROCCO

Purpose. The aim of the present work was to study the antifungal activity of Pseudomonas fluorescens strain FSJ-3 against some yeasts and filamentous pathogenic fungi. Materials and methods. Two methods have been used for determination of antifungal activity: the disc agar diffusion method and a micromethod. The molecular size of antifungal substances was estimated by filtration of crude extract through a membrane concentrator. Results. Using a micromolar concentratins, a crude filtrate of FSJ-3 culture showed in vitro antifungal activity against Cryptococcus neoformans, Aspergillus fumigatus, Arthroderma simii and some other fungi. It inhibited growth, spores, germination and hyphal elongation. Morphological alterations could be also observed. The antifungal activity was markedly reduced by heat treatment at 120 degrees C for 15 mn. The antifungal agent has a molecular size smaller than 3,000-Da. Conclusion. The FSJ-3 P. fluorescens strain was found to elaborate antifungal substances effective against yeasts and filamentous fungi which are pathogenic for humans. The isolation and molecular structure determination of the antifungal agent(s) are now under studies.