Factors affecting the resistance of Lactobacillus fermenti to lysozyme.

The sensitivity of Lactobacillus fermenti ATCC 9338 to lysozyme has its peak during the exponential phase of growth, after the autolytic activity of the organism has begun to decline. Cells from the stationary growth phase are resistant to lysozyme. The two lytic activities require different ionic conditions for their functioning; they appear mutually exclusive. Incubation with trypsin renders cells from all growth phases sensitive to lysozyme. The effect of trypsin is independent of the presence of lysozyme and vice versa, as demonstrated by use of trypsin inhibitors. Cells from early stationary phase of growth require higher temperature for optimum lysozyme action than do those from the exponential growth phase.