Anthem Biosciences Pvt. Ltd., Bommasandra Industrial Area Phase-I, Hosur Road, Bangalore, 560099, India.
Probiotics Antimicrob Proteins. 2018 Dec;10(4):717-727. doi: 10.1007/s12602-017-9321-7.
Loss in probiotic viability upon exposure to stressful storage and transport conditions has plagued the probiotic market worldwide. Lactobacillus acidophilus is an important probiotic that is added to various functional foods. It is known to be fairly labile and susceptible to temperature variations that it encounters during processing and storage which increases production cost. It has been repeatedly demonstrated that pre-exposure to sub-lethal doses of stress, particularly, temperature and pH, leads to improved survival of various probiotics when they subsequently encounter the same stress of a much greater magnitude. Attempts to adapt L. acidophilus to temperatures as high as 65 °C to arrive at a thermotolerant variant have not been reported previously. To improve viability at elevated temperatures, we gradually adapted the L. acidophilus NCFM strain to survival at 65 °C for 40 min. Following adaptation, the variant showed a 2-log greater survival compared to wild-type at 65 °C. Interestingly, this thermotolerant variant also demonstrated a 2-log greater stability compared to wild-type at pH 2.0. The improved pH and temperature stress tolerance exhibited by this variant remained unaltered even when the strain was lyophilized. Moreover, the thermotolerant variant demonstrated improved stability compared to wild-type when stored for up to a week at 37 and 42 °C. Probiotic properties of the variant such as adherence to epithelial cells and antibacterial activity remained unaltered. This strain can potentially help address the issue of significant loss in viable cell counts of L. acidophilus which is typically encountered during probiotic manufacture and storage.
在有压力的储存和运输条件下，益生菌的存活率会降低，这一问题一直困扰着全球的益生菌市场。嗜酸乳杆菌是一种重要的益生菌，被添加到各种功能性食品中。众所周知，它相当不稳定，容易受到加工和储存过程中遇到的温度变化的影响，这增加了生产成本。已经反复证明，预先暴露于亚致死剂量的应激，特别是温度和 pH 值，会导致各种益生菌在随后遇到更大程度的相同应激时，存活率提高。以前没有报道过试图使嗜酸乳杆菌适应高达 65°C 的温度，以获得耐热变体。为了提高在高温下的存活率，我们逐渐使嗜酸乳杆菌 NCFM 菌株适应在 65°C 下生存 40 分钟。适应后，与野生型相比，该变体在 65°C 下的存活率提高了 2 个对数级。有趣的是，与野生型相比，这种耐热变体在 pH 2.0 下也表现出 2 个对数级的更高稳定性。即使在冻干时，该变体表现出的改善的 pH 和温度应激耐受性也没有改变。此外，与野生型相比，耐热变体在 37°C 和 42°C 下储存长达一周时，稳定性也得到了改善。该变体的益生菌特性，如对上皮细胞的黏附性和抗菌活性保持不变。这种菌株有可能有助于解决在益生菌制造和储存过程中通常会遇到的嗜酸乳杆菌活菌数显著损失的问题。
