Faculty of Biotechnology, School of Life Sciences, SARI, Jeju National University, Jeju, 63243, Republic of Korea.
Subtropical/tropical Organism Gene Bank, Jeju National University, Jeju, 63243, Republic of Korea.
J Microbiol. 2021 Feb;59(2):217-227. doi: 10.1007/s12275-021-0525-x. Epub 2021 Feb 1.
In vitro fecal fermentation is an assay that uses fecal microbes to ferment foods, the results of which can be used to evaluate the potential of prebiotic candidates. To date, there have been various protocols used for in vitro fecal fermentation-based assessments of food substances. In this study, we investigated how personal gut microbiota differences and external factors affect the results of in vitro fecal fermentation assays. We used Cheonggukjang (CGJ), a Korean traditional fermented soybean soup that is acknowledged as healthy functional diet. CGJ was digested in vitro using acids and enzymes, and then fermented with human feces anaerobically. After fecal fermentation, the microbiota was analyzed using MiSeq, and the amount of short chain fatty acids (SCFAs) were measured using GC-MS. Our results suggest that CGJ was effectively metabolized by fecal bacteria to produce SCFAs, and this process resulted in an increase in the abundance of Coprococcus, Ruminococcus, and Bifidobacterium and a reduction in the growth of Sutterella, an opportunistic pathogen. The metabolic activities predicted from the microbiota shifts indicated enhanced metabolism linked to methionine biosynthesis and depleted chondroitin sulfate degradation. Moreover, the amount of SCFAs and microbiota shifts varied depending on personal microbiota differences. Our findings also suggest that in vitro fecal fermentation of CGJ for longer durations may partially affect certain fecal microbes. Overall, the study discusses the usability of in vitro gastrointestinal digestion and fecal fermentation (GIDFF) to imitate the effects of diet-induced microbiome modulation and its impact on the host.
体外粪便发酵是一种使用粪便微生物来发酵食物的方法，其结果可用于评估益生元候选物的潜力。迄今为止，已有各种基于体外粪便发酵的食物物质评估的方案。在这项研究中，我们研究了个体肠道微生物群差异和外部因素如何影响体外粪便发酵试验的结果。我们使用了韩国传统发酵大豆汤清曲酱（Cheonggukjang，CGJ），它被认为是健康的功能性饮食。CGJ 先用酸和酶进行体外消化，然后用人类粪便进行厌氧发酵。粪便发酵后，使用 MiSeq 分析微生物群，使用 GC-MS 测量短链脂肪酸（SCFA）的量。我们的结果表明，CGJ 被粪便细菌有效地代谢生成 SCFA，这一过程导致 Coprococcus、Ruminococcus 和 Bifidobacterium 的丰度增加，机会性病原体 Sutterella 的生长减少。从微生物群变化预测的代谢活性表明，与蛋氨酸生物合成相关的代谢增强和硫酸软骨素降解减少。此外，SCFA 的量和微生物群的变化取决于个体微生物群的差异。我们的研究结果还表明，CGJ 的体外粪便发酵时间延长可能会对某些粪便微生物产生部分影响。总的来说，该研究讨论了体外胃肠道消化和粪便发酵（GIDFF）模拟饮食诱导的微生物组调节及其对宿主的影响的可用性。
