High density fermentation for beta-fructofuranosidase production by recombinant Escherichia coli BL21(DE3) using exponential fed-batch culture strategy

Abstract:

[Objective] To study the high density fermentation process for beta-fructofuranosidase production by recombinant Escherichia coli BL21(DE3)/pET22b-β-ffase. [Methods] we compared the influence of the dissolved oxygen feedback control and the exponential fed-batch culture on the β-FFase production of the Escherichia coli BL21(DE3)/pET22b-β-ffase fermentation, and the specific growth rate and induction time were optimized. [Results] This study confirmed the specific growth rate during the dual-stage specific growth rate controlled exponential fed-batch culture. Specific growth rate were controlled at 0.20 h?1 and 0.13 h?1 in pre-induction phase and late phase after induction respectively, the express system can be induced at mid-logarithmic phase. Finally, cell dry weight reached up to 51 g/L, the peak of activity attained at 1.79×105 U/L, the unit cell enzyme activity leaped to 3 510 U/g, and the enzyme production rate reached up to 3.58×104 U/(L·h). The biomass, the unit cell enzyme activity and the enzyme production rate have been strikingly improved, which were 1.8-fold, 1.7-fold and 3.0-fold compared with values of pre-exponential feeding culture without optimization. [Conclusion] Dual-stage specific growth rate controlled exponential fed-batch culture significantly contributes to improve the enzyme β-fructofuranosidase production, and also lays the foundation for the further industrialization of the enzyme.