Production and Partial Characterization of Antifungal Substances Antagonistic toMonilinia fructicolafromBacillus subtilis

Publisher Website
Google Scholar
Abstract
Antibiotic substances produced by a strain of Bacillus subtilis previously found to suppress development of brown rot of stone fruit were produced in a synthetic medium and isolated from the cell-free medium by precipitation by acidification to less than pH 2.5. Impurities were removed by extraction with ethyl acetate and acetone. The active fraction was extracted from the precipitate with 80% ethanol. This extract contained antibiotics that were soluble in ethanol, methanol, isopropanol, and water above pH 7.5; but not soluble in ethyl acetate, acetone, ether, or methylene chloride. Thin-layer chromatographic separation of the extract indicated four biologically active bands. The extract was active against a wide range of plant pathogenic fungi and was fungistatic, not fungicidal, against spores of Monilinia fructicola. When tested for activity against M. fructicola on peach fruit, the extract showed almost complete suppression of brown rot at 1 mg/ml.