Increase Butanol Production from Corn Straw by Mineral Compounds Supplementation

Abstract

In this study, two types of fermentation methods: SSF and consolidation SHF/SSF were used for production of acetone-butanol-ethanol (ABE) from corn straw as a feedstock. Clostridium acetobutylicum DSM1731 was used as the fermenting organism. Corn straw was thermochemically pretreated and then hydrolyzed using three types of enzymes. The impact has been investigated on the effect of mineral compounds supplementation ((NH4)2SO4, MgSO4, (NH4)3PO4) on ABE productivity and butanol content. From the SSF, where mineral salts were supplemented into the fermentation medium, it was found that the maximum ABE and butanol concentrations were 28.35 g/L and 24.03 g/L, respectively, corresponding to a productivities of 0.295 g/L/h (ABE) and 0.250 g/L/h (butanol). In the consolidation SHF/SSF method with mineral compounds supplementation, the maximum ABE and butanol concentrations were 31.35 g/L and 28.64 g/L, respectively, corresponding to productivities of 0.327 g/L/h (ABE) and 0.298 g/L/h (butanol). Compared to control samples, mineral salts supplementation had a positive effect on cellular metabolic activities, leading to an earlier initiation of the solventogenesis stage. In supplemented samples, an increase in the rate of ABE fermentation by Clostridium was observed.