FIG. 3.

Proposed pathways of LA metabolism by bacterial species isolated from the human gut. The open arrows represent the bacterial activity of Lactobacillus, Propionibacterium, and Bifidobacterium species leading to the formation of CLA. The shaded arrows represent the bacterial activity of some Lactobacillus, Propionibacterium, and Bifidobacterium species and some Clostridium-like bacteria belonging to clusters IV (e.g., Eubacterium siraeum) and XIVa (e.g., R. intestinalis and Roseburia faecis) leading to the formation of HFA. The solid arrows represent the bacterial activity of Clostridium-like bacteria belonging to cluster XIVa leading to the formation of VA (e.g., Roseburia hominis and R. inulinivorans). The dotted arrows represent activities observed in fecal microbiota for which the responsible bacterial species are still unknown.