Fig. 7

Purification of I-FOS from the production solution with activated charcoal. a Eluted amounts of fructose, glucose, sucrose, and I-FOS in each elution step. E = elution fraction. Brackets indicate ethanol concentrations in % [v/v]. b I-FOS recovery and purity in pooled elution fractions. For purification, 100 g activated charcoal was incubated with 21 mL process solution from the 10 L scale I-FOS production diluted in 1 L water for 45 min at 40 °C and 250 rpm in a temperature-controlled shaking incubator. Elution steps were carried out at 40 °C and 250 rpm with 1 L solvent (0–80% ethanol [v/v]). Details are present in the materials and methods section. Sugar and I-FOS concentrations were determined via isocratic HPLC using 58% [v/v] acetonitrile at a flow rate of 0.7 mL min⁻¹. The experiment was performed in technical triplicates. Standard deviations are indicated by error bars