In vitro fermentation of chitooligosaccharides and their effects on human fecal microbial community structure and metabolites

Xiao-Guo Ji^a, Kun-Lin Chang^a, Mai Chen^a, Liang-Liang Zhu^a, Arwa Osman^a, Hao Yin^b, Li-Ming Zhao^a,c

State Key Laboratory of Bioreactor Engineering, School of Biotechnology, East China University of Science and Technology, Shanghai, 200237, China.

Abstract

Chitooligosaccharides (COS), with a specific degree of polymerization, were evaluated for their effect on human fecal microbiota, as well as their metabolite, using an in vitro anaerobic batch fermentation model. COS increased the richness and diversity of the gut microbial community. More importantly, the microbial community structure of the COS groups was significantly different from the control and fructooligosaccharides (FOS) groups. COS specifically enriched the butyric and propionic acid-producing microbiota and targeted Faecalibacterium, Clostridium_sensu_stricto_1, C._sensu_stricto_13, and Fusicatenibacter. Furthermore, COS increased the acetic, propionic, and butyric acid contents. The production of propionic acid was greater than that obtained using FOS. Metabolome analysis suggested that COS could upregulate allocholic acid, 1,3-butanediol, 3,4-dihydroxybutanotic acid, and 2-hydroxybutyric acid production and downregulate putrescine, ethanamine, hexanoic acid, and branched chain amino acid (l-valine and l-leucine) production in the fermentation broth. These differential metabolites were closely related to lipid, glucose, and amino acid metabolism. These results should inform further development of COS as potential raw materials for functional foods and health products.

Keywords: Chitooligosaccharides, In vitro fermentation, Gut microbes, Short-chain fatty acid, Differential metabolites.