Wheat bran promotes enrichment within the human colonic microbiota of butyrate-producing bacteria that release ferulic acid.
Wheat bran promotes enrichment within the human colonic microbiota of butyrate-producing bacteria that release ferulic acid.
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DOI：
10.1111/1462-2920.13158
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发表时间：
2016-07
影响因子：
5.1
通讯作者：
Flint HJ
中科院分区：
文献类型：
--
作者：
Duncan SH;Russell WR;Quartieri A;Rossi M;Parkhill J;Walker AW;Flint HJ
小麦麸皮等谷物纤维被认为通过对肠道微生物群的影响而对人类健康有益。我们通过基于16S rRNA基因的群落分析表明，在厌氧发酵罐中，将淀粉酶预处理的麦麸作为人类肠道微生物群落的唯一添加能源，导致少量细菌物种的选择性和渐进性富集。特别地，对应于未培养的毛螺菌科（厚壁菌门）的OTU与嗜木聚糖肠杆菌和B utyrivibrio spp.在用不同的粪便接种物进行的四个独立实验中，在48小时内强烈富集（5至160倍），而其他九个厚壁菌门OTU在至少一个实验中显示> 5倍富集。阿魏酸在降解过程中从麦麸中释放出来，但通过氢化、去甲基化和去羟基化迅速转化为苯丙酸衍生物，得到在人类粪便样品中检测到的代谢物。使用与富集的OTU相关的细菌分离株（包括几种丁酸生产菌）的纯培养工作证明，菌株引起底物重量损失并释放阿魏酸，但进一步转化有限。我们得出结论，麦麸的分解涉及专业的初级降解剂，而释放的阿魏酸的转化可能涉及多物种途径。
Cereal fibres such as wheat bran are considered to offer human health benefits via their impact on the intestinal microbiota. We show here by 16S rRNA gene‐based community analysis that providing amylase‐pretreated wheat bran as the sole added energy source to human intestinal microbial communities in anaerobic fermentors leads to the selective and progressive enrichment of a small number of bacterial species. In particular, OTUs corresponding to uncultured Lachnospiraceae (Firmicutes) related to E ubacterium xylanophilum and B utyrivibrio spp. were strongly enriched (by five to 160 fold) over 48 h in four independent experiments performed with different faecal inocula, while nine other Firmicutes OTUs showed > 5‐fold enrichment in at least one experiment. Ferulic acid was released from the wheat bran during degradation but was rapidly converted to phenylpropionic acid derivatives via hydrogenation, demethylation and dehydroxylation to give metabolites that are detected in human faecal samples. Pure culture work using bacterial isolates related to the enriched OTUs, including several butyrate‐producers, demonstrated that the strains caused substrate weight loss and released ferulic acid, but with limited further conversion. We conclude that breakdown of wheat bran involves specialist primary degraders while the conversion of released ferulic acid is likely to involve a multi‐species pathway.