Fermentation broth was also mixed with white carbon black (20%
w/v) for preparing spray-drying wettable powder that used as control.
The inoculated media were dried using a mini Spray Dryer
DS-1500 (Juyuan Automation Technology Co., Ltd., Shanghai,
China). The spray-drying conditions for determining the optimum
concentration of maltodextrin and gum arabic were as follows:
air-inlet temperature of 145 C, feed flow rate of 550 mL h1, and
spray pressure of 0.2 MPa. Each experiment was repeated
three times.