Abstract:In this study,butanol production from corn stover hydrolyzate by Clostridium saccharobutylicum DSM 13864 was investigated.The medium composition was optimized by orthogonal method as follows:CaCO3 2.0 g/L,(NH4)2SO4 1.0 g/L,K2HPO4 0.5 g/L,corn steep powder 15 g/L,and MnSO4·H2O 0.01 g/L.In a 3 L bioreactor,total solvent of 16.1 g/L(butanol 10.59 g/L) was reached after 40 h of fermentation,and the productivity and yield were 0.40 g/(L·h) and 0.33 g/g,respectively.Batch fermentation process using temperature-shifting demonstrates that lower temperature is beneficial to the solvent accumulation.Compared with temperature-constant process(37 ℃),total solvent was increased from 17.01 g/L to 19.98 g/L.The temperature-shifting continuous fermentation process was operated for 269 h at dilution rate of 0.1 h-1,and the solvent production entered a stable phase at around 80 h.The average solvent during the stable solvent-production stage is 12.28 g/L(including 8.50 g/L butanol),and the average solvent productivity is 1.23 g/(L·h),representing 4.92 times of temperature-shifting batch fermentation(D).
