Effects of carbon sources and lipids on freeze-drying survival of Lactobacillus bulgaricus in growth media

The aim of this study was to investigate the effects of various substrate supplements in the growth media on the synthesis of cyclopropane fatty acid (cycC19:0) and freeze-drying survival rate of Lactobacillus bulgaricus L2 and their relatedness. Survival rate during freeze-drying was enhanced markedly (P < 0.05) when cells were grown in the presence of Tween 20 and sucrose as compared with the control. However, the survival rate of L. bulgaricus was lower when cells were grown in the presence of sugars (mannitol, maltose, dextrin and trehalose) and Tween (Tween 40 and Tween 60) relative to the control. Compared with the control, cells with a higher freeze-drying survival rate exhibited a higher cycC19:0 content of change. There was no linear correlation between these two parameters.