Fig. 3

Schematic experimental fermenter setup for concentrated liquid and solid fructose feeding. Extended batch fermentations were performed with A concentrated liquid fructose solutions and B solid fructose cubes. A: Fructose feed solutions were constantly stirred and heated to ~ 55 °C in a bottle using a heating magnetic stirrer. The peripheral feeding system was heated to ~ 55 °C using hot water or an electrical heating band with insulation (indicated with dark red lines). B: Fructose cubes were stored in a bottle attached to a silicon tube with a 2 cm diameter. The silicon tube was sealed with three hose clamps, to prevent humidity entering the storage bottle from the fermenter. For feeding, desired numbers of cubes were manually transferred from the bottle to the tube and into the fermenter. Schematic representation adapted from [91]. Parts of the figure were drawn by using pictures form Servier Medical Art, provided by Servier, licensed under a Creative Commons Attribution 3.0 unported license