Enhanced 2,3-butanediol production by Klebsiella oxytoca using a two-stage agitation speed control strategy

Abstract

Batch fermentative production of 2,3-butanediol by Klebsiella oxytoca was investigated using various oxygen supply methods though varying agitation speed. Based on the analysis of three kinetic parameters including specific cell growth rate ( μ), specific glucose consumption rate ( q s ) and specific 2,3-butanediol formation rate ( q p ), a two-stage agitation speed control strategy, aimed at achieving high concentration, high yield and high productivity of 2,3-butanediol, was proposed. At the first 15 h, agitation speed was controlled at 300 rpm to obtain high μ for cell growth, subsequently agitation speed was controlled at 200 rpm to maintain high q p for high 2,3-butanediol accumulation. Finally, the maximum concentration of 2,3-butanediol reached 95.5 g l −1 with the yield of 0.478 g g −1 and the productivity of 1.71 g l −1 h −1, which were 6.23%, 6.22% and 22.14% over the best results controlled by constant agitation speeds.