## 3 Results
### Fermentation of Fractan-Type Carbohydrates by BB-12 and Complex Microbiota (Experiment 3)
OTU = operational taxonomic unit; BB-12 = _Bifidobacterium animalis_ subsp. _lactis_; OF = oligofructose; IN = inulin; SD = standard deviation; SEM = standard error of means. stronger increases in gas production. Some additional changes were observed when BB-12 was co-administered with fructans. Dosing BB-12 together with OF2 further enhanced acetate levels, while BB-12 treatment together with OF2, OF/IN2 and IN3 further stimulated propionate production. Finally, BB-12 enhanced butyrate levels upon co-administration with OF/IN1, IN1 and IN2. Finally, quantitative 16S-targeted Illumina sequencing was performed to obtain insights in microbial composition changes upon treatment with BB-12 and/or the different fructans. Data are presented at phylum (Table 3 for average of the donors and Table S2 shows the data per individual donor) and family level (Table 4 for average of the donors and Tables S3-S5 for the data at per individual donor), while also the 20 most abundant OTUs are reported (Table 5 for average of the donors and Tables S6-S8 for the data per individual donor). \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Input**} & **Blank** & **OF1** & **OF2** & **OF/IN1** & **OF/IN2** & **IN1** & **IN2** & **IN3** \\ \cline{2-19}  & **BB-12** & **-** & **BB-12** & **-** & **BB-12** & **-** & **BB-12** & **-** & **BB-12** & **-** & **BB-12** & **-** & **BB-12** \\ \hline pH & 0.00 & \(\mathbf{-0.93}\) & 0.07 & \(\mathbf{-0.97}\) & 0.02 & \(\mathbf{-0.86}\) & 0.01 & \(\mathbf{-0.78}\) & 0.05 & \(\mathbf{-0.68}\) & \(\mathbf{-0.03}\) & \(\mathbf{-0.80}\) & 0.00 & \(\mathbf{-0.77}\) & 0.01 \\ Gas (GPa) & **2.4** & **28.1** & 2.9 & **21.5** & **4.6** & **30.6** & 3.48 & \(\mathbf{0.9}\) & \(\mathbf{-1.3}\) & **45.9** & 1.0 & **45.0** & 0.7 & **43.8** & 2.2 \\ Acetate (mM) & 0.6 & **20.4** & \(\mathbf{-0.2}\) & **20.1** & **4.3** & **22.5** & 1.0 & **23.6** & \(\mathbf{-0.3}\) & **24.6** & \(\mathbf{-2.8}\) & **26.3** & \(\mathbf{-4.2}\) & **24.5** & 1.0 \\ Lactate (mM) & 0.1 & **15.1** & \(\mathbf{-0.9}\) & **15.1** & \(\mathbf{-1.2}\) & **14.1** & \(\mathbf{-1.2}\) & **7.5** & 0.3 & **7.6** & 0.5 & **8.1** & 0.2 & **9.2** & \(\mathbf{-0.2}\) \\ Propionate (mM) & **0.4** & 0.2 & 0.4 & 0.6 & **0.9** & 1.0 & 0.1 & **4.3** & **1.2** & **5.5** & \(\mathbf{-0.1}\) & **4.4** & 0.3 & **3.4** & **1.2** \\ Butyrate (mM) & 0.1 & 2.4 & 0.6 & 0.2 & 0.3 & 1.9 & **1.1** & **5.5** & 1.4 & **5.9** & **1.4** & **4.2** & **1.9** & **5.6** & \(\mathbf{-0.1}\) \\ bCFA (mM) & 0.1 & \(\mathbf{-2.8}\) & 0.0 & \(\mathbf{-2.8}\) & 0.0 & \(\mathbf{-2.8}\) & 0.1 & \(\mathbf{-2.7}\) & 0.0 & \(\mathbf{-2.7}\) & 0.1 & \(\mathbf{-2.8}\) & 0.1 & \(\mathbf{-2.7}\) & 0.1 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Changes in metabolic activity upon dosing BB-12 and/or seven fructans with short (OF1, OF2), intermediate (OF/IN1, OF/IN2) and high degree of polymerization (IN1, IN2 and IN3) to the complex microbiota of three human donors (C, D and F). The values represent average differences over the three donors versus the respective reference (for fructans, the reference was the untreated blank, while for conditions with BB-12 addition this was the respective condition where BB-12 was not dosed). The data represent the average changes between 0–48 h (except for the intermediate metabolite lactate where it is the maximal value measured throughout the incubation). Significant changes are indicated in bold (\(n=9\); 3 values for each of the 3 donors).