The seed cultures were cultivated in 500-mL flasks containing
50 mL of the seed medium on a rotary shaker for 12 h. Fermentation
was carried out in a 7-L fermentor jar (BioFlo 410-7L, New
Brunswick Scientific, Enfield, CT, USA) with 4 L of the fermentation
medium. The inoculation size was 10% (v/v) of the fermentation
medium; the pH and aeration rate were controlled at 6.5 and
4 L/min, respectively.