Extractive fermentation of Kytococcus sedentarius TWHKC01 using the aqueous biphasic system for direct recovery of keratinase

Abstract

BackgroundExtractive fermentation using aqueous biphasic system (ABS) can integrate the cultivation of microbial cells and direct recovery of the target enzyme into a one-step operation which simplifies the overall time and costs for the recovery processes. MethodsABS extractive fermentation was applied in this study for the fermentation and instant recovery of Kytococcus sedentarius TWHKC01 keratinase. The polyethylene glycol (PEG) 2000 and sodium citrate were used as the ABS phase components for the cells growth and keratinase production. FindingsA total of 182.44 U/mL of keratinase was recovered in the top phase of the ABS composed of 25% (w/w) PEG 2000 and 10% (w/w) tri-sodium citrate which was higher than the fermentation without integrated with ABS (161.33 U/mL). Repetitive batch fermentation was performed with the ABS by retaining the K. sedentarius TWHKC01 cells in the bottom phase of the ABS and continuously recovering the keratinase from top phase. The relative keratinase activity decreases from 1.12 to 0.60 after four batches of the ABS extractive fermentation. ABS extractive fermentation is a promising approach to integrate the fermentation and recovery of keratinase enzyme with a single-step operation.