Figure 5.

16S rRNA gene analysis for potential butyrate-producing taxa is shown as percentages of the total 16S rRNA gene sequences. Data were searched on a genus level and subsequently categorized into butyryl-CoA:acetate CoA-transferase (but: bluish colors) and butyrate kinase (buk; reddish colors)-linked taxa. The applied gene association should not be regarded as strict for those taxa as several genera contain both but and buk as well as non-butyrate-producing members (see main text). Thus, this type of analysis cannot substitute for a functional gene-targeted approach but is used here for global comparisons. Taxa associated with alternative transferases (other: yellowish colors) or amino-acid-fed butyrate-producing pathways (aa; greenish colors) are shown. Individual genera from the same family were combined (see Supplementary Table S1).