STELA Dairy Research Center, Nutraceuticals and Functional Foods Institute, Pavillon des services, University of Laval, Quebec, QC, Canada.
J Appl Microbiol. 2010 Jul;109(1):54-64. doi: 10.1111/j.1365-2672.2009.04644.x. Epub 2009 Dec 4.
To evaluate the survival of Pediococcus acidilactici UL5 and its ability to produce pediocin PA-1 during transit in an artificial gastrointestinal tract (GIT). To investigate the physicochemical and biological stability of purified pediocin PA-1 under GIT conditions.
Skim milk culture of Ped. acidilactici UL5 was fed to a dynamic gastrointestinal (GI) model known as TIM-1, comprising four compartments connected by computer-controlled peristaltic valves and simulating the human stomach, duodenum, jejunum and ileum. This strain tolerated a pH of 2·7 in the gastric compartment, while lower pH reduced its viability. Bile salts in the duodenal compartment brought a further 4-log reduction after 180 min of digestion, while high viable counts (up to 5 × 10(7) CFU ml(-1) fermented milk) of Ped. acidilactici were found in both the jejunal and ileal compartments. Pediococcus acidilactici recovered from all four compartments was able to produce pediocin at the same level as unstressed cells. The activity of the purified pediocin in the gastric compartment was slightly reduced after 90 min of gastric digestion, while no detectable activity was found in the duodenal, jejunal and ileal compartments during 5 h of digestion. HPLC analysis showed partial degradation of the pediocin peptide in the duodenal compartment and massive breakdown in the jejunal and ileal compartments.
Pediococcus acidilactici UL5 showed high resistance to GIT conditions, and its ability to produce pediocin was not affected, suggesting its potential as a probiotic candidate. The physicochemical and biological stability of pediocin was significantly poor under GIT conditions.
Pediococcus acidilactici UL5 appears to be a potential probiotic candidate because its capacity to produce pediocin PA-1 is not affected by the GI conditions as well as the strain shows an acceptable survival rate. Meanwhile, purified pediocin PA-1 losses activity during GIT transit; microcapsules could be used to deliver it to the target site.
评估乳球菌 UL5 在人工胃肠道（GIT）转运过程中的生存能力及其产生抑菌素 PA-1 的能力。研究抑菌素 PA-1 在 GIT 条件下的物理化学和生物学稳定性。
将乳球菌 UL5 的脱脂乳培养物喂给称为 TIM-1 的动态胃肠道（GI）模型，该模型由四个通过计算机控制的蠕动阀连接的隔室组成，模拟人体的胃、十二指肠、空肠和回肠。该菌株能在胃隔室耐受 pH2.7，而较低的 pH 值会降低其存活率。在消化 180 分钟后，十二指肠隔室中的胆汁盐又使活菌数减少了 4 个对数级，而在空肠和回肠隔室中均发现了高达 5×10(7)CFU ml(-1)发酵乳的高活菌数。从所有四个隔室回收的乳球菌 UL5 均能以与未受应激细胞相同的水平产生抑菌素。在胃消化 90 分钟后，胃隔室中纯化抑菌素的活性略有降低，而在 5 小时的消化过程中，在十二指肠、空肠和回肠隔室中均未发现活性。HPLC 分析表明，在十二指肠隔室中抑菌素肽部分降解，在空肠和回肠隔室中大量降解。
乳球菌 UL5 对 GIT 条件具有高抗性，并且其产生抑菌素的能力不受影响，表明其作为益生菌候选物的潜力。抑菌素在 GIT 条件下的物理化学和生物学稳定性明显较差。
乳球菌 UL5 似乎是一种有潜力的益生菌候选物，因为其产生抑菌素 PA-1 的能力不受 GI 条件的影响，而且该菌株具有可接受的存活率。同时，纯化的抑菌素 PA-1 在 GIT 转运过程中失去活性；微胶囊可用于将其递送到靶位。
