Influence of the incubation temperature on the autolytic activity of Lactobacillus acidophilus

The effect of temperature and growth phase on the autolysis of Lactobacillus acidophilus CRL 640 was studied. The maximal rate of autolytic activity (ca 48% cell lysis) was found at 45 degrees C. At this temperature, two peaks were detected: the first one at the early exponential phase of growth and the second lysis peak during the transition stage from the exponential to the stationary phase. The release of intracellular compounds absorbing at 260 and 280 nm was also detected at 45 degrees C. The microscopic observations revealed morphological changes and the presence of ghost cells. At 37 degrees C, the low autolytic activity obtained would be related to the normal cell cycle of growth.