Metabolism of glyphosate by the human fecal microbiota

Glyphosate is the most frequently used herbicide worldwide and its application is under discussion due to health concerns. As humans may be exposed to glyphosate, the present study investigated the metabolism of glyphosate by the human fecal microbiota in vitro. Human fecal samples were collected from 15 different volunteers and fecal suspensions were prepared. The human fecal suspension samples were incubated with glyphosate under strictly anaerobic conditions and glyphosate degradation was investigated. Neither a degradation of glyphosate, nor a formation of AMPA (aminomethylphosphonic acid), the known microbial metabolite in soil, was detected. In conclusion, the microbiota of human fecal suspensions did not metabolize glyphosate under the conditions used in our study which hints at the assumption that transformation of glyphosate by the gut microbiota seems to be negligible in humans.