Evaluation of microbial-fructo-oligosaccharides metabolism by human gut microbiota fermentation as compared to commercial inulin-derived oligosaccharides

The prebiotic potential of fructo-oligosaccharides (microbial-FOS) produced by a newly isolated Aspergillus ibericus, and purified by Saccharomyces cerevisiae YIL162 W, was evaluated. Their chemical structure and functionality were compared to a non-microbial commercial FOS sample. Prebiotics were fermented in vitro by fecal microbiota of five healthy volunteers. Microbial-FOS significantly stimulated the growth of Bifidobacterium probiotic strains, triggering a beneficial effect on gut microbiota composition. A higher amount of total short-chain fatty acids (SCFA) was produced by microbial-FOS fermentation as compared to commercial-FOS, particularly propionate and butyrate. Inulin neoseries oligosaccharides, with a degree of polymerization (DP) up to 5 (e.g., neokestose and neonystose), were identified only in the microbial-FOS mixture. More than 10% of the microbial-oligosaccharides showed a DP higher than 5. Differences identified in the structures of the FOS samples may explain their different functionalities. Results indicate that microbial-FOS exhibit promising potential as nutraceutical ingredients for positive gut microbiota modulation.Dalila Roupar: Soraia Silva and Marta Coelho acknowledge the Portuguese Foundation for Science and Technology (FCT) for their PhD Grants (SFRH/BD/139884/2018, SFRH/BD/136471/2018, and SFRH/BD/111884/2015, respectively). Elisabete Coelho thanks the research contract (CDL-CTTRI 88-ARH/2018-REF. 049-88-ARH/2018) funded by national funds (OE), through FCT, in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. This study was supported by the FCT under the scope of the strategic funding of UIDB/04469/2020 and UIDB/50016/2020 unit, and LAQV/REQUIMTE (UIDB/50006/2020, UIDP/50006/2020) through national founds and, where applicable, co-financed by the FEDER, within the PT2020 Partnership Agreement, and the Project ColOsH PTDC/BTM-SAL/30071/2017, also by the European Regional Development Fund (ERDF) through the Competitiveness factors Operational program, Norte 2020, COMPETE, and by National Funds through the FCT under the project AgriFood XXI (NORTE-01-0145-FEDER-000041), and the project cLabel+ (POCI-01-0247-FEDER-046080) co-financed by Compete 2020, Lisbon 2020, Portugal 2020 and the European Union, through the European Regional Development Fund (ERDF).