1 Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia.
2 Competence Center of Food and Fermentation Technologies, Akadeemia tee 15A, 12618 Tallinn, Estonia.
Benef Microbes. 2018 Jan 29;9(1):21-34. doi: 10.3920/BM2016.0198. Epub 2017 Oct 12.
The metabolic activity of colon microbiota is specifically affected by fibres with various monomer compositions, degree of polymerisation and branching. The supply of a variety of dietary fibres assures the diversity of gut microbial communities considered important for the well-being of the host. The aim of this study was to compare the impact of different oligo- and polysaccharides (galacto- and fructooligosaccharides, resistant starch, levan, inulin, arabinogalactan, xylan, pectin and chitin), and a glycoprotein mucin on the growth and metabolism of faecal microbiota in vitro by using isothermal microcalorimetry (IMC). Faecal samples from healthy donors were incubated in a phosphate-buffered defined medium with or without supplementation of a single substrate. The generation of heat was followed on-line, microbiota composition (V3-V4 region of the 16S rRNA using Illumina MiSeq v2) and concentrations of metabolites (HPLC) were determined at the end of growth. The multiauxic power-time curves obtained were substrate-specific. More than 70% of all substrates except chitin were fermented by faecal microbiota with total heat generation of up to 8 J/ml. The final metabolite patterns were in accordance with the microbiota changes. For arabinogalactan, xylan and levan, the fibre-affected distribution of bacterial taxa showed clear similarities (e.g. increase of Bacteroides ovatus and decrease of Bifidobacterium adolescentis). The formation of propionic acid, an important colon metabolite, was enhanced by arabinogalactan, xylan and mucin but not by galacto- and fructooligosaccharides or inulin. Mucin fermentation resulted in acetate, propionate and butyrate production in ratios previously observed for faecal samples, indicating that mucins may serve as major substrates for colon microbial population. IMC combined with analytical methods was shown to be an effective method for screening the impact of specific dietary fibres on functional changes in faecal microbiota.
肠道微生物的代谢活性受到具有不同单体组成、聚合度和支化度的纤维的特异性影响。各种膳食纤维的供应确保了肠道微生物群落的多样性，这些群落被认为对宿主的健康很重要。本研究旨在使用等温微量热法（IMC）比较不同的寡糖和多糖（半乳糖和果寡糖、抗性淀粉、莱鲍迪苷、菊粉、阿拉伯半乳聚糖、木聚糖、果胶和几丁质）以及糖蛋白黏蛋白对体外粪便微生物群生长和代谢的影响。将来自健康供体的粪便样品在磷酸盐缓冲的定义培养基中孵育，有或没有单一底物的补充。在线跟踪产热量，在生长结束时确定微生物群落组成（使用 Illumina MiSeq v2 的 16S rRNA 的 V3-V4 区）和代谢物浓度（HPLC）。获得的多需氧动力-时间曲线是特定于底物的。除几丁质外，超过 70%的所有底物都被粪便微生物群发酵，总产热量高达 8 J/ml。最终的代谢物模式与微生物群的变化一致。对于阿拉伯半乳聚糖、木聚糖和莱鲍迪苷，受纤维影响的细菌分类群分布显示出明显的相似性（例如，卵形拟杆菌和青春双歧杆菌的增加）。阿拉伯半乳聚糖、木聚糖和黏蛋白增强了丙酸的形成，丙酸是一种重要的结肠代谢物，但半乳糖和果寡糖或菊粉则没有。黏蛋白发酵产生了乙酸盐、丙酸盐和丁酸盐，其比例与以前观察到的粪便样品一致，这表明黏蛋白可能是结肠微生物群的主要底物。研究表明，IMC 与分析方法相结合是一种有效的方法，可用于筛选特定膳食纤维对粪便微生物群功能变化的影响。
