Pretreatment with a combination of steam explosion and NaOH increases butanol production of enzymatically hydrolyzed corn stover
Zhicai Zhang, Huihua Zheng, Jingya Qian
Abstract
As an essential lignocellulosic source, corn stover (CS) arouses an extensive interest in transforming into bio-butanol and high-value-added products. Optimization experiments of medium and kinetic fermentation experiments of Clostridium acetobutylicum CICC 8008 were conducted. The CS was pretreated by a combination of steam explosion and NaOH, followed by saccharification by cellulase. The saccharification liquor contained 65.91 g/L of total reducing sugar. The optimum fermentation medium was 1,000 mL saccharification liquor supplemented with 4.89 g/L yeast extract, 6.9 g/L CaCO3, and 10.56 mg/L biotin. When the optimum medium was used in the butanol fermentation process, the maximum acetone-butanol-ethanol (ABE) content was 41.78 g/L, and the contents of acetone, butanol, and ethanol were 9.73, 23.82, and 8.23 g/L, respectively. The maximum specific growth rate was 0.066 h−1, the coefficient of growth was 2.29 g/(gL), and no substrate and production inhibition were found. ABE was the growth-associated metabolite. Collectively, our current findings provided valuable insights into the efficient application of lignocellulose biomass into the biorefinery of butanol.