Enhancement of Butanol Production in a Newly Selected Strain through Accelerating Phase Shift by Different Phases C/N Ratio Regulation from Puerariae Slag Hydrolysate

To obtain native strains to efficiently use puerariae slag (PS) hydrolysate and resistant butanol toxicity, a self-designed isolation method was adopted. With this effort, the strain YBS3 was obtained. Based on 16S rDNA comparison, the strain YBS3 was identified as Clostridium beijerinckii. The feasibility of using PS hydrolysate as substrate to produce butanol was evaluated. A significant phase shift delay was encountered in acetone-butanol-ethanol (ABE) fermentation process, and then leaded to low production and productivity of butanol. However, when the C/N ratio regulation strategy was performed at mid-logarithmic phase, the problem of the phase shift delay was smoothly solved and the yield and productivity of butanol was improved. Specifically, the final production and productivity of butanol were 9.75 ± 0.14 g/L and 0.18 g/(L·h), respectively, which was 46.40% and 125.00% higher than without C/N ratio regulation. This study confirms that the accelerating phase shift is a convenient but effective approach, thereby is a promising technology for improving ABE fermentation performance.