Modulation of human gut microbiota by linear and branched fructooligosaccharides in an in vitro colon model (TIM-2)

Aims: This study aimed to compare the effects of linear and branched fructooligosaccharides (FOS) extracted from chicory and grass (Lolium perenne), respectively on human microbiota composition, diversity, and metabolism. Methods and results: To test the effects of linear and branched FOS on human microbiota we used the artificial in vitro human colon model (TIM-2). Microbiota composition and diversity were assessed by V3–V4 16S rRNA metagenomic sequencing, followed by differential taxa abundance and alpha/beta diversity analyses. SCFA/BCFA production was evaluated by gas chromatography–mass spectrometry. As a result, branched FOS had the most beneficial effects on microbial diversity and metabolite production. Also, branched FOS significantly increased the abundance of commensal bacteria associated with maintaining healthy gut functions and controlling inflammation, such as Butyricicoccus, Erysipelotrichaceae, Phascolarctobacterium, and Sutterella. Linear FOS also significantly increased the abundance of some other commensal gut bacteria (Anaerobutyricum, Lachnospiraceae, Faecalibacterium), but there were no differences in diversity metrics compared to the control. Conclusions: The study revealed that branched FOS had the most beneficial effects compared to the linear FOS in vitro, concerning microbiota modulation, and metabolite production, making this a good candidate for further studies in food biotechnology. Impact Statement In this study, branched FOS had more beneficial effects on human gut microbiota in vitro in comparison to linear FOS, as it promotes the growth of commensal bacteria associated with gut health, and increases microbial diversity and metabolite production. These findings will be the basis for further functional food products development.