Fed-Batch Fermentation of L-Asparaginase

Abstract:

L-asparaginase（EC 3.5.1.1，L-ASNase）has been widely used in the fields of food and medicine. In order to achieve the efficient production of L-ASNase，the effects of stirring speed and fed-batch fermentation conditions on the cell growth and enzyme production of /Bacillus subtilis//ASNΔ25/B2 were investigated in 3 L fermenter. After the optimization，conditions used for fed-batch fermentation were determined as follows：the stirring speed was set at 700 r/min for the first 8 h and shifted to 900 r/min till the end of the fermentation；for fermentation at 16~28 h，sucrose solution（800 g/L）and nitrogen sources（yeast peptone：200 g/L；corn syrup：80 g/L）were fed at 18.75 mL/h and 32 mL/h，respectively. Based on this fermentation condition，the L-ASNase yield reached 1 413.6 U/mL at 48 h，which was 66.2% higher than that of batch fermentation. The final production intensity obtained here was 24.6% higher than that of the latter. The results provide the basic data for the industrial production of the recombinant L-ASNase.