2.4.2. Pilot scale fermentation
Pilot scale fermentation was carried out in a 72 L BIOSTAT UD bioreactor containing 45 L of coffee pulp hydrolysate and 10 g L1 yeast extract. Fermentation was carried out at 52 C and pH 6. Due to limitations in coffee pulp, fermentation was carried out only once. Stirring occurred at 400 rpm using a double Rushton turbine. Regulation of pH was carried out by adding 20% (w/w) NaOH. A 5% (v/v) inoculum was used. The inoculum was grown for 17 h in a 5 L fermentation vessel containing 2 L of medium consisting of 66 g L1 dextrose monohydrate and 15 g L1 yeast extract inoculated with 120 mL MRS culture . Samples were taken regularly and treated as described in Section 2.4.1. After fermentation, culture broth was inactivated at 85 C for 30 min and stored at 20 C until used in downstream processing.