Enhanced biobutanol production from fern root using Clostridium Acetobutylicum CGMCC1.0134 with yeast extract addition

Abstract

Fern root (FR) was used in the biofuel production for the first time. However, fermentation of the enzymatic hydrolysate of FR starch (EHFS) directly to butanol by Clostridium acetobutylicum CGMCC1.0134 resulted in a low butanol production and yield with high content of starch residual. After adding yeast extract (YE) solution (with a 3 g/L final concentration in broth) into EHFS, the butanol production, productivity, and yield were raised by 174%, 250%, and 183%, respectively. Monitoring changes of free amino acid concentration in the fermentation broth indicated that aspartic acid families and serine families were stimulated to accumulate by YE addition. Gene expression analysis further revealed that ctfB coding CoA-transferase was induced by adding YE into EHFS. It was concluded that EHFS could be a promising substrate for butanol fermentation.