Abstract
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 Eubacterium xylanophilum and Butyrivibrio spp. were strongly enriched (by five to 160 fold) over 48 hours 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, demethoxylation 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.
| Original language | English |
|---|---|
| Pages (from-to) | 2214-2225 |
| Number of pages | 12 |
| Journal | Environmental Microbiology |
| Volume | 18 |
| Issue number | 7 |
| Early online date | 21 Jan 2016 |
| DOIs | |
| Publication status | Published - 8 Jul 2016 |
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Wheat bran promotes enrichment within the human colonic microbiota of butyrate-producing bacteria that release ferulic acid. / Duncan, Sylvia H; Russell, Wendy R; Quartieri, Andrea; Rossi, Maddalena; Parkhill, Julian; Walker, Alan W; Flint, Harry J.
In: Environmental Microbiology, Vol. 18, No. 7, 08.07.2016, p. 2214-2225.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Wheat bran promotes enrichment within the human colonic microbiota of butyrate-producing bacteria that release ferulic acid
AU - Duncan, Sylvia H
AU - Russell, Wendy R
AU - Quartieri, Andrea
AU - Rossi, Maddalena
AU - Parkhill, Julian
AU - Walker, Alan W
AU - Flint, Harry J
N1 - This article is protected by copyright. All rights reserved. Acknowledgements: The authors acknowledge support from the Scottish Government Food Land and People programme (RESAS). We would like to thank Lorraine Scobbie and Gary Duncan for technical support. Funding for JP, AWW and 454 pyrosequencing was provided by the Wellcome Trust (grant number 098051).
PY - 2016/7/8
Y1 - 2016/7/8
N2 - 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 Eubacterium xylanophilum and Butyrivibrio spp. were strongly enriched (by five to 160 fold) over 48 hours 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, demethoxylation 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.
AB - 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 Eubacterium xylanophilum and Butyrivibrio spp. were strongly enriched (by five to 160 fold) over 48 hours 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, demethoxylation 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.
U2 - 10.1111/1462-2920.13158
DO - 10.1111/1462-2920.13158
M3 - Article
VL - 18
SP - 2214
EP - 2225
JO - Environmental Microbiology
JF - Environmental Microbiology
SN - 1462-2912
IS - 7
ER -