Antagonistic Compounds Produced by a Chicken Intestinal Strain of Lactobacillus acidophilus

The production of antagonistic compounds was studied with a strain of Lactobacillus acidophilus isolated from chicken intestinal tract. Accumulation of lactic acid (0.15 mol/l), hydrogen peroxide (280 nmol/h/mg cell dry weight), and a bacteriocin (ca. 10,000 arbitrary activity units per ml) was observed in cultures of this strain. In conditions eliminating the effects of organic acids and hydrogen peroxide, the bacteriocin, designated LA-147, showed inhibitory activity against strains of Lactobacillus leichmannii but not against several other species of Lactobacillus , or other selected gram-positive and gram-negative species. LA-147 (MW ca. 38.5 kDa) was bactericidal against sensitive cells; it was inactivated by heating for 15 min at 100°C, and by the action of protease and alpha-chymotrysin.