Production of organic acids, carbon dioxide and ethanol (A), biogenic amines and branched-chain fatty acids (B), and production/consumption of amino acids (C) (mmol/gDW) during growth of fecal consortia in media containing levan (in red), levan + amino acids (in green) or without added substrates (in blue).

<p>The data presents the average of all fecal samples (n = 11 with 1–4 biological replicates). Dotted line indicates the zero level (no production or consumption). *—significant difference between levan and no-substrate conditions (p-value < 0.05), **—significant difference between levan and levan + amino acids (p-value < 0.05), ***—significant difference between levan and levan + amino acids and no substrate conditions (p-value < 0.05).</p

Content of organic acids in fecal cultures (μmol/g±SD) analyzed before each cultivation experiment (2–4 calorimetry replicates per sample).

<p>Complete data shown in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0144042#pone.0144042.s003" target="_blank">S3 Table</a>.</p

Bacterial taxa in individual fecal samples and their abundance after the growth in microcalorimeter.

<p>(A) 22 bacterial taxa of fecal samples (FS1-11) with average abundance ≥ 1% are shown (sum of reads in relative scale, %). (B) abundance of genera (family/order level if the genus was not identified) per million cells (1 read = 1 cell) after growth on levan (red dots), levan plus amino acids (green triangles) or without added substrates (blue rectangles) in a logarithmic scale. All data points presented as average values of all fecal samples. *—statistical difference between the samples with levan and without added substrates (p-value < 0.05), **—statistical difference between the samples with levan and levan + amino acids (p-value < 0.05).</p

Proposed scheme for levan degradation and product formation on the basis of our experimental data and information from the literature.

<p>Proposed scheme for levan degradation and product formation on the basis of our experimental data and information from the literature.</p

Growth characteristics of fecal consortia on media of varied composition.

<p>(A) Growth of fecal cultures from group I (FS1-5) on medium without levan and amino acids. (B) Growth of fecal cultures from group II (FS6-11) on medium without levan and amino acids. (C) Growth of fecal cultures from group I on medium with levan. (D) Growth of fecal cultures from group II on medium with levan. μ - specific growth rate (h^-1), Q—heat accumulated (J) and P_max—maximum heat evolution rates (power, μW) achieved in different growth phases. Growth phase is defined as time between the power peak maxima, <i>i</i>.<i>e</i>. each power peak divides growth into two phases: before and after power peak maximum. Error bars indicate standard deviation of 2–4 biological replicates. Line graphs illustrate the heat evolution rate (P–power, μW) during the whole experiment. Note that line graphs on consortia growth with and without levan have different Y axis scale.</p