The solvent productivity and yield were both at a low level of 0.12 g/(L h) and 0.29 g/g.
Most of the sugars including 20 g/L glucose
and 15 g/L xylose were left in the culturemedium,
suggesting that
culture medium
with 61 g/L total sugars was not
feasible
during butanol production.
The results also suggested that improving the tolerance of C. acetobutylicum strain to NaCl or exploring new method for phase separation should be carried out in future work.
During ABE fermentation, acetic acid and butyric acid could be produced and re-assimilated,
while the total concentration of two acids at the end of fermentation with 61 g/L sugars was 1.42 times higher than that with 41 g/L sugars,
which might suggest that more acids were produced to generate ATP for cell metabolism when exposed to inhibiting environment.
Butanol production from acid hydrolyzed sugarcane bagasse was reported by Soni et al. [27] and this process only produced 3.5 g/L butanol, while 10.8 g/L butanol was obtained after detoxification with active carbon.
In present study, sugarcane bagasse hydrolysate with low concentration of inhibitors was generated by using GVL/water solution and high concentration of butanol was produced without any detoxification step, which will greatly contribute to the low-cost production of biobutanol.