PURIFICATION AND CHARACTERIZATION OF NEW FATTY-ACIDS WITH ANTIBIOTIC-ACTIVITY PRODUCED BY SPOROTHRIX FLOCCULOSA

Chloroform extracts from a culture broth of the biocontrol fungus Spor othrix flocculosa were separated by thin-layer chromatography (TLC). C ompounds with antifungal activity were revealed with the Cladosporium cucumerinum bioassay on TLC plates and were isolated by using silica g el column, preparative TLC, and reverse-phase high-performance liquid chromatography (RP-HPLC). They were identified by standard methods of nuclear magnetic resonance (NMR), gas chromatography (GC), mass spectr ometry (MS), and infrared spectrum (IR). In addition to an active mole cule previously described, two new fatty acids with antibiotic activit y were characterized, 9-heptadecenoic acid and 6-methyl-9-heptadecenoi c acid, the latter displaying the strongest activity among all three a ctive molecules. This high number of active metabolites produced by S. flocculosa would explain its rapid and strong activity as a biocontro l agent of powdery mildews. In this context, screening of S. flocculos a isolates for increased production of these molecules should help in selection of candidates with superior biocontrol properties.