Study on Antifungal Activities and Stability of Fermentation Broth from Streptomycetes albidoflavus S417 Strain

16 species of plant pathogenic fungi were tested for antifungal spectrum by Streptomycetes albidoflavus S417 strain using mycelial growth rate method.Colletotrichum musae was applied as the indicator fungi to study the antimicrobial activity of the fermentation broth by different treatments of physical-chemical factors by means of cylinder-plant assay.The fermentation broth of strain S417 had varying degrees of inhibitory activity towards 16 species of pathogenic fungi.Among these,activity against C.musae,E.turcicum and 3 other pathogens with an inhibitory rate of 82.53 %-69.63 % was highest in tested fungi.The antifungal activity of fermentation broth was stable at 120 ℃ for 20 minutes.Ultraviolet irradiation for 25 minutes had no significant influence on the activity of antifungal substance.The fermentation broth had no activity after sunshine irradiation for 4 hours.It was stable under acid or neural conditions and kept the highest antifungal activity at the pH6.0.