Characteristics of bacterial enzymes present during in vitro fermentation of chicory root pulp by human faecal microbiota

Research was conducted to understand cell wall polysaccharide (CWPs) degradation in chicory root pulp (CRP) during an in vitro fermentation by human faecal microbiota. Enzyme extracts (EEs) from CRP fermentation liquids (2, 12 and 24 h) were tested for enzyme activities towards p-nitrophenyl-glycosides and polysaccharides. The EEs were also incubated for 24 h on polysaccharides and cell wall residues (CWRs) derived from CRP, to determine the mechanism and efficiency of enzyme action. The study showed that the presence of arabinofuranosidase, β-galactosidase, endo-arabinanase, endo-galactanase and exo-polygalacturonase increased for the 24 h EE, whereas the activity of enzymes degrading (hemi)cellulose was highest in the 12 h EE. It was hypothesised that increased levels of arabinofuranosidase, β-galactosidase, endo-arabinanase, endo-galactanase, exo-polygalacturonase, pectin de-esterifying enzymes and endo-polygalacturonase contributed to a synergy in degrading pectin in CRP from 12 to 24 h of fermentation. The higher degradability of arabinan compared to galactan in the network is due to the architecture in CRP involving more accessible arabinan than galactan.