Saprophytes Antagonistic to Phytopathogenic and Other Microorganisms

Abstract

The bactericidal properties of Bacillus vulgatus and an unidentified yellow spore-bearing bacillus were described. The bactericides produced by the antagonists are water soluble and active in extremely small amts. They are not affected by pH. The active principle was not precipitable by inorganic acids, (NH4)2SO4, aluminum sulfate, Al nitrate, alcohols, and ether. The bactericidal substances were absorbed by Berkefield filters but that of Bacillus vulgatus passed through a Chamberland L3 filter. Boiling for 60 min. did not destroy the bactericide of either antagonist but when the bactericidal containing medium of the yellow species was autoclaved, the bactericide was inactivated after 15 min. at 10 lbs. pressure. That of Bacillus vulgatus was still active after 10 min. at 20 lbs. pressure.