Stress adaptation and cross-protection of Lactobacillus plantarum KLDS 1.0628

Various stresses are commonly encountered by probiotics in their ecological niches. Effects of adaptation treatments on the heat tolerance of Lactobacillus plantarum KLDS 1.0628 were evaluated. Cells pre-adapted to heat, cold, oxidative, acid, bile salt, and osmotic stresses were evaluated for tolerance and cross-protection against subsequent challenge. Except for cold, pre-adaptation to sublethal levels of stress significantly improved the cell viability after heat challenge compared to the control. Heat-adapted cells showed the highest heat stress tolerance, with their tolerance factor against heat challenge reaching 31.38-fold after pre-adaptation at 45 degrees C for 1 h. Moreover, adaptation treatments improved tolerance to the same stress and evoked cross-protection against heterologous challenges, inducing a significantly lower ratio of saturated to unsaturated fatty acid content in the cell membrane of L. plantarum KLDS 1.0628. The results indicated that adaptation treatments are potential strategies for enhancing the survival rate of probiotics and exerting their functional properties.